Dissertations / Theses: 'Metalling'

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Davies, Hugh E. H. "Design and construction of Roman roads in Britain." Thesis, University of Reading, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.343169.

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Witt, Kevin L. "Development of a Ti:W salicide-nitride based multilayer metallization for VLSI application /." Online version of thesis, 1992. http://hdl.handle.net/1850/11045.

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Cheng, Han-Hao. "Metallic nanotransistors." Thesis, University of Canterbury. Electrical and Computer Engineering, 2008. http://hdl.handle.net/10092/2604.

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Efforts to downscale transistor dimensions to satisfy the demands for ultra high density integrated circuits have been met so far with optical lithography techniques. However, they are now facing their fundamental limits including optical diffraction and the limits associated with UV exposure sources. The feature size required for current integrated circuits is 45nm. In the near future it is predicted to reach 15nm node where conventional photolithography can no longer be employed. As a result, extensive research has been devoted into the development of next generation lithography processes and new transistor structures. Among the potential candidates for next generation transistor devices, nanowire based field effect structures made from a single layer of metal are proposed. These types of transistors are designed to operate similarly to a depletion type of MOSFET by governing the flow of electrons in a narrow nanowire channel. In this study, metallic nanowire structures were designed, fabricated and tested. Nanowires with diameters as small as 12.5nm were fabricated using electron beam lithography (EBL), thermal evaporation and metal lift-off process. Optimisations of EBL parameters were made to deliver wires ranging from 200nm down to 12.5nm mainly by suppressing charging effects and minimising factors that contribute to proximity effects. These structures were the first in the Nanofabrication laboratory at the University of Canterbury to be fabricated with such dimensions. Nanowire structures in Y shaped and planar gated configurations have also been tested using Ag, Al, and NiCr. Metallic nanowire devices were deposited on insulating substrates such as Si₃N₄ or SiO₂ to facilitate electrical characterisation and device operation. In the fabrication, the minimum achievable line widths is mainly determined by the surface charging effects due to the direct EBL patterning on insulating substrates and by proximity effects for having gate structures located few tens of nanometres away from the main nanowire. Electrical characterisations including two point, four point, transmission line measurements, and gate effects were performed using semiconductor parameter analyser to study the conduction and gating effect of these nanowires with gate electrodes that are separated by air gaps in the range of 20nm-200nm. The main challenging issues found to affect the characterisation results are the voltage offset problem during four point resistance measurement, the charge fluctuation and the effect of joule heating during long integration measurements. To further study the gate effects of nanowires based on semi-metals, focused ion beam (FIB) technology was employed for the fabrication of bismuth nanotransistor structures, with minimum dimensions in the 30nm scale. In addition, we have for the first time report the creation of highly ordered and multiple layers of nano dots stacking using electron beam induced metal deposition in FIB. In this thesis, although no significant gating effects were observed due to difficulties involved in further reducing the nanowire widths beyond the 12nm node, the fabrications and characterisations of these nanowire structures have allowed us to explore the resolution limits of these processes and at the same time create a platform suitable for studying the conduction characteristics, transport properties and the gate effects for nanowires made from semiconductor, metal and semimetal.

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Brown, Matthew George. "Ion scattering studies of metallic and complex bi-metallic systems." Thesis, University of Warwick, 2010. http://wrap.warwick.ac.uk/3625/.

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5

Masood, Ansar. "Functional Metallic Glasses." Doctoral thesis, KTH, Teknisk materialfysik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-101901.

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For decades, Metallic Glass, with its isotropic featureless structure while exhibiting outstanding mechanical properties was possible only at a high rate of quenching and with at least one dimension in the submicron regime. This limitation was overcome with the discovery of Bulk Metallic glasses, BMGs, containing three or more elements following the additional two empirical rules of optimum geometric size differences and negative energy of mixing among the constituent elements. Since then thousands of Fe-, Ni-, Al-, Mg-, Ti- based BMGs have been discovered and comprehensively investigated mainly by groups in Japan and USA. Yet the discovery of new combinations of elements for BMGs is alchemy. We do not know with certainty which element when added will make possible a transition from being a ribbon to a bulk rod. In this thesis we report a discovery of castable BMGs rods on substitution of Fe by nickel in an alloy of FeBNb which could otherwise have been only melt-spun into ribbons. For example, we find that substitution of just 6 at.% of Fe raises the glass forming range, GFA, to as much as ∆Tx =40K while the other parameters for GFA like Trg, γ, and δ reach enhanced values 0.57, 0.38, and 1.40 respectively. Furthermore, the electrical conductivity is found to increase by almost a factor of two. Magnetically it becomes softer with coercivity 260mOe which further reduces to much lower values on stress relaxation. Ni does not seem to carry a magnetic moment while it enhances the magnetic transition temperature linearly with Ni concentration. We have investigated the role of Ni in another more stable BMGs based FeBNbY system in which case ∆Tx becomes as large as 94K with comparable enhancement in the other GFA parameters. Due to the exceptional soft magnetic properties, Fe-based bulk metallic glasses are considered potential candidate for their use in energy transferring devices. Thus the effect of Ni substitution on bulk forming ability, magnetic and electrical transport properties have been studied for FeBNb and FeBNbY alloy systems. The role of Ni in these systems is densification of the atomic structure and its consequence. We have exploited the superior mechanical properties of BMGs by fabricating structures that are thin and sustainable. We have therefore investigated studies on the thin films of these materials retaining their excellent mechanical properties. Magnetic properties of FeBNb alloy were investigated in thin films form (~200-400nm) in the temperature range of 5-300K. These Pulsed Laser deposited amorphous films exhibit soft magnetism at room temperature, a characteristic of amorphous metals, while they reveal a shift in hysteresis loop (exchange anisotropy, HEB=18-25Oe), at liquid helium temperature. When thickness of films is reduced to few nanometers (~8-11nm), they exhibit high transparency (>60%) in optical spectrum and show appreciably high saturation Faraday rotation (12o/μm, λ= 611nm). Thin films (~200-400nm) of Ni substituted alloy (FeNiBNb) reveal spontaneous perpendicular magnetization at room temperature. Spin-reorientation transition was observed as a function of film thickness (25-400nm) and temperature (200-300K), and correlated to the order/disorder of ferromagnetic amorphous matrix as a function of temperature. These two phase films exhibits increased value of coercivity, magnetic hardening, below 25K and attributed to the spin glass state of the system. Using the bulk and thin films we have developed prototypes of sensors, current meters and such simple devices although not discussed in this Thesis. Ti-based bulk metallic glasses have been attracting significant attention due to their lower density and high specific strength from structural application point of view. High mechanical strength, lower values of young’s modulus, high yield strength along with excellent chemical behaviors of toxic free (Ni, Al, Be) Ti-based glassy metals make them attractive for biomedical applications. In the present work, toxic free Ti-Zr-Cu-Pd-Sn alloys were studied to optimize their bulk forming ability and we successfully developed glassy rods of at least 14mm diameter by Cu-mold casting. Along with high glass forming ability, as-casted BMGs exhibit excellent plasticity. One of the studied alloy (Ti41.5Zr10Cu35Pd11Sn2.5) exhibits distinct plasticity under uniaxial compression tests (12.63%) with strain hardening before failure which is not commonly seen in monolithic bulk metallic glasses.

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Leung, Chi Wah. "Metallic magnetic heterostructures." Thesis, University of Cambridge, 2002. https://www.repository.cam.ac.uk/handle/1810/34608.

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This work studied sputter deposited conventional spin valves (SV) and related structures. In SV layered structures, two ferromagnetic layers are separated by a non-magnetic spacer. Under an external magnetic field, the relative orientation of the magnetization changes in the ferromagnets, exhibiting the giant magnetoresistive effect. The controlled switching of ferromagnets in convention SV is facilitated by the exchange bias (EB) effect, which is achieved by depositing an antiferromagnetic layer next to one of the ferromagnetic layers in a magnetic field. Two highly related investigations were performed in this work. In the first part the exchange bias effect in the Ni80Fe20/Fe50Mn50/Co trilayer structure was studied. Samples were deposited in a low field condition that permitted EB to be established in NiFe/FeMn but not in FeMn/Co bilayer structures. Temperature-dependent magnetic measurements were performed on the trilayer sample, as well as the corresponding NiFe/FeMn and FeMn/Co bilayer samples. Recent literature on similar system showed that an AF spiral could be formed in the trilayer, which was probed by relative EB directions of the NiFe and Co layers. In this work, no exchange bias was found to propagate from the NiFe/FeMn system into the FeMn/Co system, showing that the AF spiral was induced by the specific magnetic treatment and was not the cause of EB effect. Besides, exchange bias field and coercivity of the samples indicated the influence of the EB system in the presence of an adjacent EB system. Explanations of the effect were made with some existing EB models. In the second part of the work, conventional SV of target structure Nb/NiFe/Cu/Co/FeMn/Nb was studied in a 'built-up samples' strategy. A batch of these built-up samples, which corresponded to the different stages of the deposition of the target top conventional SV structure, were prepared by terminating the sputtering process after a certain number of layers were deposited. These samples were thoroughly characterized by structural, magnetic and electrical measurements. In terms of structural characterization by x-ray techniques, more reliable information concerning the morphology and microstructure of the layers was obtained by probing the built-up samples, instead of relying solely on the information of the full SV structure. For the electric and magnetic measurements, a number of unexpected observations were made in the built-up samples, although the final performance of the full SV structure was of comparable quality to the literature. These results showed the ability of the 'built-up samples' strategy in critical characterization and optimization of magnetic multilayered structures.

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Abboud, Jaafar Hadi. "Laser surface alloying of titanium by metallic and non-metallic additions." Thesis, Imperial College London, 1990. http://hdl.handle.net/10044/1/47732.

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8

Murray, Patrick W. "Comparison of non-metallic to metallic lath reinforcement in stucco cladding systems." [Gainesville, Fla.] : University of Florida, 2006. http://purl.fcla.edu/fcla/etd/UFE0015691.

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9

Armstrong, William D. "Thermal cycling damage accumulation processes in an advanced metal matrix composite /." Thesis, Connect to this title online; UW restricted, 1991. http://hdl.handle.net/1773/7075.

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Rogacki, John R. "A combined experimental analytical methodology for characterizing the thermoviscoplastic deformation of a metal matrix composite /." Thesis, Connect to this title online; UW restricted, 1992. http://hdl.handle.net/1773/7083.

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Lee, Jae-Kon. "Thermal cycling and creep resistance of metal matrix composites /." Thesis, Connect to this title online; UW restricted, 1996. http://hdl.handle.net/1773/7103.

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12

Siegrist, Marco E. "Bulk metallic glass composites /." Zürich : ETH, 2007. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=16998.

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13

Grupe, Sven. "Perrhenate mit dreiwertigen Metallen." [S.l. : s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=967442435.

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14

Woldt, E. "Relaxation in metallic glasses." Thesis, University of Cambridge, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382709.

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15

Yang, Fu-Liang. "Interdiffusion in metallic multilayers." Thesis, University of Cambridge, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.360566.

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Conyers, James Scott. "Diffusion in metallic multilayers." Thesis, University of Cambridge, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.621609.

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17

Idapalapati, Sridhar. "Compaction of metallic powders." Thesis, University of Cambridge, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.624169.

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Tam, Hoi Lam. "Active textured metallic microcavity." HKBU Institutional Repository, 2004. http://repository.hkbu.edu.hk/etd_ra/613.

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Heien, Bjonge Ingrid, and Marcus Hofflander. "Automatiserad sortering avsekundär metallisk råvara." Thesis, KTH, Tillämpad maskinteknik (KTH Södertälje), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-215874.

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20

Calla, Eklavya. "Cold gas spraying of copper and tin onto metallic and non metallic substrates." Thesis, University of Nottingham, 2005. http://eprints.nottingham.ac.uk/12455/.

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Cold gas dynamic spraying (CGDS) is a recent development in the field of thermal spraying in which a powder feedstock can be deposited onto a substrate to form a coating without it being heated significantly. The aim of the present study was to investigate the potential for manufacturing electrical circuits for automobile applications by depositing copper tracks on non-metallic substrates. Powders were sprayed using He gas at room temperature and elevated temperatures onto a number of different polymers, ceramic and metal substrates to understand the factors controlling deposit formation and the development of adequate adhesion between track and substrate. The use of tin as an interlayer to improve adhesion was a novel development in this study. The deposits were characterized by optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD), profilometry, microhardness, tensile testing, adhesion testing and resistivity measurements. Investigations were also performed to study thermal stability since as sprayed deposits are in non-equilibrium state. Copper could be deposited on aluminium for a wide range of deposition parameters. Sprayed copper had nanometre size grains and demonstrated high hardness and tensile strength. Annealing resulted in recrystallization and grain growth and decrease in hardness and tensile strength. Copper could be deposited on polymers like nylon (PA66), glass reinforced nylon (PA6T) and poly (butylene terepthalate) (PBT). Copper could be deposited on a wide range of polymers when a layer of tin was deposited as a bond coat. The use of tin bond coat improved the overall adhesion of tin + copper tracks. Intermetallic compound formation was observed in tin - copper tracks after annealing at 343 K and 443 K. The formation of the intermetallic compound did not increase the resistance of tin - copper couples as the resistance of the couples after annealing were found to be below that of the as - sprayed couples where the intermetallic compound formation had not taken place. This effect is a result of the recovery/recrystallization taking place in copper which reduces the resistance.

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Nakhodchi, Soheil. "Prediction and Measurement of Strains and Stresses in Metallic and Non-Metallic Materials." Thesis, University of Bristol, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.525436.

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Cottrell, Craig Ashley. "The interaction of Hâ†2, Dâ†2 with metallic and bi-metallic surfaces." Thesis, University of Liverpool, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.265125.

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23

Rodekohr, Chad L. Bozack Michael J. Flowers George T. "Material factors influencing metallic whisker growth." Auburn, Ala, 2008. http://repo.lib.auburn.edu/EtdRoot/2008/FALL/Mechanical_Engineering/Dissertation/Rodekohr_Chad_16.pdf.

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24

Jin, Ohchang. "Damage accumulation and life prediction of titanium matrix composites subjected to elevated temperatures." Thesis, Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/19542.

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Müggenburg, Jan. "Ion beam analysis of metallic vanadium superlattices : Ion beam analysis of metallic vanadium superlattices." Thesis, Uppsala universitet, Tillämpad kärnfysik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-328067.

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Tijiwa, Birk Felipe. "Spin electronics in metallic nanoparticles." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/39525.

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The work presented in this thesis shows how tunneling spectroscopy techniques can be applied to metallic nanoparticles to obtain useful information about fundamental physical processes in nanoscopic length scales. At low temperatures, the discrete character of the energy spectrum of these particles, allows the study of spin-polarized current via resolved "electron-in-a-box" energy levels. In samples consisting of two ferromagnetic electrodes tunnel coupled to single aluminum nanoparticles, spin accumulation mechanisms are responsible for the observed spin-polarized current. The observed effect of an applied perpendicular magnetic field, relative to the magnetization orientation of the electrodes, indicates the suppression of spin precession in such small particles. More generally, in the presence of an external non-collinear magnetic field, it is the local field "felt" by the particle that determines the character of the tunnel current. This effect is also observed in the case where only one of the electrodes is ferromagnetic. In contrast to the non-magnetic case, ferromagnetic nanoparticles exhibit a much more complex energy spectrum, which cannot be accounted for, using the simple free-electron picture. It will be shown that interactions between quasi-particle excitations due to sequential electron tunneling and spin excitations in the particle are likely to play an important role in the observed temperature/voltage dependence of magnetic hysteresis loops.

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Chandrasekaran, Shankar. "Surface micromachined hollow metallic microneedles." Diss., Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/15505.

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Cambron, André. "Hydrogen in NiZr metallic glasses." Thesis, McGill University, 1986. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=66070.

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Cui, Xudong. "Photonic crystals with metallic inclusions /." Zürich : ETH, 2006. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=16933.

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Lintz, William A. "Electromagnetic resonances of metallic bodies." Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1997. http://handle.dtic.mil/100.2/ADA333440.

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Thesis (M.S. in Electrical Engineering) Naval Postgraduate School, June 1997.
Thesis advisors, Richard W. Adler, Jovan E. Lebaric. Includes bibliographical references (p. 45). Also available online.

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Hübschen, Bettina. "Grundlagenuntersuchungen zur Tiefenfiltration von Metallen /." Aachen : Shaker, 2004. http://bvbr.bib-bvb.de:8991/F?func=service&doc_library=BVB01&doc_number=013109603&line_number=0001&func_code=DB_RECORDS&service_type=MEDIA.

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Corkery, Robert, and robert corkery@anu edu au. "Artificial biomineralisation and metallic soaps." The Australian National University. Research School of Physical Sciences and Engineering, 1998. http://thesis.anu.edu.au./public/adt-ANU20080124.190014.

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In this thesis, geometry is used as a basis for conducting experiments aimed at growing and arranging inorganic minerals on curved interfaces. Mineralisation is directed using crystalline and liquid-crystalline metallic soaps and surfactant/water systems as templates.¶ A review of the history, syntheses, structure and liquid crystallinity of metallic soaps and other amphiphiles is presented as a foundation to understanding the interfacial architectures in mesostructured template systems in general.¶ In this study, a range of metallic soaps of varying chain length and cation type are synthesised and characterised to find potentially useful templates for mineral growth. These include alkaline-earth, transition metal, heavy metal and lanthanide soaps. These are systematically characterised using a variety of analytical techniques, including chemical analyses, x-ray diffraction (XRD) infrared spectroscopy (IR) and differential scanning calorimetry (DSC). Their molecular and crystal structures are studied using transmission electron microscopy (TEM), cryo-TEM, electron diffraction (ED), electron paramagnetic spin resonance (EPR), absorption spectroscopy (UV-VIS), high resolution laser spectroscopy, atomic force microscopy (AFM), nuclear magnetic resonance spectroscopy, scanning electron microscopy (SEM), electron dispersive x-ray analysis (EDXA), thermal gravimetric analysis (TGA) and magnetic measurements. Models for the molecular and crystal structures of metallic soaps are proposed. The soaps are predominantly lamellar crystalline or liquid crystalline lamellar rotor phases with tilted and/or untilted molecular constituents. These display evidence of varying degrees of headgroup organisation, including superstructuring and polymerisation. A single crystal structure is presented for a complex of pyridine with cobalt soap. Simple models for their structure are discussed in terms of their swelling properties in water and oils. Experiments are also presented to demonstrate the sorbent properties of aluminium soaps on oil spills.¶ The thermotropic liquid crystallinity of alkaline earth, transition metal, heavy metal and lanthanide soaps is investigated in detail. This is done to assess their suitability as templates, and to document their novel thermotropic behaviour, particularly the relatively unknown lanthanide soaps. Liquid crystalline behaviours are studied using high-temperature XRD (HTXRD), hot-stage optical microscopy and DSC. Models for a liquid crystalline phase progression from crystals to anisotropic liquids are discussed in terms of theories of self-assembly and interfacial curvature. The terminology required for this is drawn from various nomenclature systems for amphiphilic crystals and liquid crystals. General agreement with previous studies is reported for known soaps, while liquid crystallinity is demonstrated in the lanthanide and some non-lanthanide soaps for the first time. A general phase progression of crystalline lamellar through liquid crystalline lamellar to non-lamellar liquid crystalline is discussed in terms of models concerned with the molecular and crystal structures of the soaps and their phase transitions via headgroup and chain re-arrangements.¶ Experiments aimed at guiding growth of metal sulfides using metallic soaps as templates are described, and a model for this growth is discussed. Metal sulfides have been successfully grown by reacting crystalline and liquid crystalline transition metal and heavy metal soaps with H2S gas at room temperature and at elevated temperature. These have been characterised using XRD, TEM, ED and IR. Sulfide growth is demonstrated to be restricted and guided by the reacting soap template architecture. Zinc, cadmium, indium and lead soaps formed confined nanoparticles within the matrix of their reacting soap template. In contrast, curved and flat sheet-like structures, some resembling sponges were found in the products of sulfided iron, cobalt, nickel, copper, tin and bismuth soaps. A model to explain this behaviour is developed in terms of the crystal and liquid crystal structures of the soaps and the crystal structures of the metal sulfide particles.¶ Liquid crystalline iron soaps have been subjected to controlled thermal degradation yielding magnetic iron oxide nanoparticles. Some XRD and TEM evidence has been found for formation of magnetic mesostructures in heat-treated iron soaps. Models for the molecular and liquid crystalline structure of iron soaps, their thermotropic phase progression and eventual conversion to these magnetic products are discussed. Systematic syntheses of mesoporous silicates from sheeted clays are discussed.¶The templates that have been used are cationic surfactants and small, organic molecular salts. Experiments are reported where a cooperative self-assembly of surfactant/water/kanemite plus or minus salt and oils yields 'folded sheet materials' (FSM'S). Templating of kanemite has also been achieved using cobalt cage surfactants. A theoretical prediction of the specific surface areas and specific volumes of homologous sets of FSM's gave excellent agreement with measured values. The geometry and topology of the mesostructures are discussed. A theoretical model is also discussed regarding the curvature found in the sheets of natural clays , and results of templating clays and silica using metallic soaps are presented. Experiments and a model for low temperature nucleation and growth of microporous silicalite-1 are described in terms of silica templating by water clathrates.¶ Finally, the problem of finding minimal surface descriptions of crystal networks is addressed. Combinatoric methods are used to disprove the existence of possible embeddings of type I and II clathrate networks in non-self intersecting periodic minimal surfaces. The crystal network of the clathrate silicate, melanophlogite is successfully embedded in the WI-10 self-intersecting surface. Details of a previously unreported, genus-25 periodic surface with symmetry Im3m are discussed.

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Bakkal, Mustafa. "Machining of Bulk Metallic Glass." NCSU, 2004. http://www.lib.ncsu.edu/theses/available/etd-06072004-004846/.

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The turning and drilling of Zr52.5Ti5Cu17.9Ni14.6Al10 metallic glass (BMG) are evaluated in this study. The mechanics of machining and chip formation and characterization are investigated. In the lathe turning of BMG, above a threshold cutting speed, the low thermal conductivity of BMG leads to chip temperatures high enough to cause the chip oxidation and associated light emission. The high temperature produced by this exothermic chemical reaction causes crystallization within the chips. Oxide layer, amorphous region, fully crystalline region, and crystalline-amorphous transition region are observed in the cross-section of the chips. The x-ray diffraction peaks match the pattern for monoclinic ZrO2. Turning chips morphology suggests that increasing amounts of viscous flow control the chip-removal process. Moreover, viscous flow and crystallization can occur during the machining of the bulk metallic glass, even under the high temperature gradient and strain rate. For the BMG chip without light emission, the serrated chip with adiabatic shear band and void formation was observed. High cutting speed significantly reduced the forces for BMG machining due to thermal softening. Roughness of machined BMG surfaces is generally better than that of Al6061-T6 and SS304. Tool wear is a problem for BMG turning. Chipping and thermal softening on the lathe tool cutting edges can be observed. Drilling of BMG shows that holes with precision geometry and good surface roughness can be efficiently produced in BMG using the high speed steel and WC-Co drills at spindle speed that does not exceed the limit for chip light emission. Morphology of BMG drilling chip are classified and analyzed. The thermal conductivity of tool material and cutting speed are concluded as two critical factors that triggered the chip exothermic oxidation and light emission. The chip light emission has profound impact on the drill wear, as shown by the experimentally measured thrust force and torque. This study concludes the precision machining of BMG is possible with the selection of feasible tools and process parameters.

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Klement, Kai. "Nichtgleichgewichtsdefekte in extrem verformten Metallen /." Göttingen : Sierke, 2007. http://bvbr.bib-bvb.de:8991/F?func=service&doc_library=BVB01&doc_number=016072212&line_number=0001&func_code=DB_RECORDS&service_type=MEDIA.

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Boufelfel, Ahmed. "Iron-based magnetic metallic superlattices." Diss., The University of Arizona, 1988. http://hdl.handle.net/10150/184340.

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For the first time we prepared and investigated the structural, magnetic, and electrical transport properties of Fe/W, Fe/Mo, and Fe/Pd metallic superlattices. We made a theoretical attempt to explain the induced increase or decrease of the magnetization at the magnetic superlattice interfaces. We used several x-ray diffraction techniques to determine the structural properties of our superlattices. Mossbauer spectroscopy and neutron scattering were used to determine the induced microscopic magnetic effects due to the superlattice structure. Brillouin scattering spectroscopy was used to determine the elastic and magnetic properties of our samples. We investigated the electrical transport properties over a wide range of temperatures of Fe/Pd and Fe/W superlattices.

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Varsani, Vijay. "Rheological behaviour of metallic liquids." Thesis, Brunel University, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.436281.

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Sullivan, J. H. "Metallic runoff from coated steels." Thesis, Swansea University, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.639132.

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An investigation was carried out to assess levels of metallic runoff, particularly zinc, from the surface and cut-edges of a variety of commercial coated steels in order to ascertain potential environmental effects in line with the ongoing EU risk assessment into zinc (1995). Zinc runoff was monitored from the surfaces of a range of zinc-coated steels with sealed edges over 19 months at two UK weathering sites. The composition of the zinc coating is crucial in determining materials performance and rainfall levels are critical in determining runoff quantity. Observed zinc runoff levels are generally below the permissible drinking water level for humans but runoff levels in the harshest environment exceed this maximum for some materials during the exposure. A range of organically coated galvanised steels were exposed for 27 months at three UK weathering sites with a large cut-edge length to assess runoff from such edges. Runoff was high in initial months with zinc levels reducing with time due to the build up/action of corrosion products and corrosion inhibitors. Zinc levels were below the permissible drinking water level. Zinc runoff measured over 3 months can more accurately predict long-term organic coating delamination than salt spray and prohesion testing. Accelerated laboratory tests using a distilled water electrolyte were developed that predict long-term external weathering runoff from panels of a range of coated steels. The angle of panel, electrolyte flow rate and wet/dry cycles affect the runoff levels of such tests. The corrosion mechanisms of a variety of zinc-coated steels have been examined using the scanning vibrating electrode technique (SVET) in 0.1%NaCl. The corrosion behaviour of a coating is related to its structure and composition. The SVET has been used to assess total zinc loss from coatings during corrosion and has been confirmed using ICP-MS analysis. The predicted zinc losses from the SVET were used to model up to 12 months external weathering behaviour for the zinc-coated steels.

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Dzyabura, Vasily. "Pathways to a Metallic Hydrogen." Thesis, Harvard University, 2013. http://dissertations.umi.com/gsas.harvard:10737.

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The primary subject of this thesis is the study of warm dense hydrogen by means of pulsed laser heating in the pressure region 1 to 2 Mbar and temperatures above the melting line, where a liquid-liquid phase transition from the insulating molecular fluid to a conducting atomic hydrogen fluid, so called plasma phase transition (PPT), was predicted to take place. The first evidence of the PPT under static compression is reported. The observations are in agreement with the negative slope phase line predicted by ab initio methods.
Physics

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Huber, Jana. "Plasmonic resonances in metallic nanoarrays." Thesis, Uppsala universitet, Materialfysik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-262269.

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The optical and magneto-optical response of plasmonic resonances in metallic nanoarrays out of square structures, either in holes or islands, were investigated. The excitation of the Bragg Plasmons takes place within a grating. Significant differences in the excited plasmon modes were seen by using p- or s-polarized light as well between the holes and islands sample. In order to investigate magneto-optical response from the magnetic nanostrucures, transverse magneto-optical Kerr effect (TMOKE) measurements were done with the result that there is a difference in holes and islands sample. Contrary to what is generally expected for the polarization dependence of TMOKE, a TMOKE signal for s-polarized light on the holes sample was measured.

40

Winter, Gemma. "Spontaneous emission near metallic interfaces." Thesis, University of Exeter, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.445441.

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41

Kitson, Stephen Christopher. "Molecular fluorescence near metallic gratings." Thesis, University of Exeter, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.260673.

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42

Amos, Richard Michael. "Molecular fluorescence above metallic surfaces." Thesis, University of Exeter, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.388590.

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43

Andrew, Piers. "Molecular fluorescence near metallic interfaces." Thesis, University of Exeter, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.265270.

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44

Dakin, Simon John. "Spin fluctuations in metallic magnets." Thesis, University of Southampton, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.359234.

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45

Bardt, Jeffrey A. "Precision molding of metallic microcomponents." [Gainesville, Fla.] : University of Florida, 2005. http://purl.fcla.edu/fcla/etd/UFE0011822.

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46

McAdon, Mark Herbert Goddard William A. "New concepts of metallic bonding." Diss., Pasadena, Calif. : California Institute of Technology, 1988. http://resolver.caltech.edu/CaltechTHESIS:10302009-113153689.

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Thesis (Ph. D.)--California Institute of Technology, 1988. UM #88-03,406.
Advisor names found in the Acknowledgments pages of the thesis. Title from home page. Viewed 01/20/2010. Includes bibliographical references.

47

Ulrich, Christian Markus. "Simulation der Laserablation an Metallen." [S.l. : s.n.], 2007. http://nbn-resolving.de/urn:nbn:de:bsz:93-opus-32961.

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48

Ropers, Claus. "Femtosecond excitations in metallic nanostructures." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2007. http://dx.doi.org/10.18452/15664.

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Diese Arbeit leistet einen Beitrag zum Verständnis optischer Anregungen in metallischen Nanostrukturen. Am Beispiel ausgewählter Strukturen werden experimentell die Dynamik dieser Anregungen mit Femtosekunden-Zeitauflösung und ihre elektromagnetischen Moden auf der Nanometer-Längenskala untersucht. Anhand winkel- und zeitaufgelöster Transmissionsexperimente an metallischen Dünnfilmgittern wird gezeigt, dass resonante Oberflächenplasmon-Polaritonen (OPPen) wesentlich die optischen Eigenschaften dieser Strukturen beeinflussen. Die Lebensdauer solcher Anregungen wird ermittelt und damit nachgewiesen, dass Kopplungen zwischen OPP-Resonanzen drastische Lebensdauer-Modifikationen zur Folge haben. In einem eigens konstruierten, spektral auflösenden optischen Nahfeldmikroskop werden die elektromagnetischen Feldverteilungen der OPPen direkt abgebildet. Derartige Experimente erlauben erstmals eine Zuordnung der räumlichen Moden zur zeitlichen Dynamik verschiedener OPP-Resonanzen. Diese Erkenntnisse ermöglichen zudem eine Interpretation des nahfeldmikroskopischen Bildkontrasts bezüglich der Beiträge verschiedener vektorieller Komponenten des optischen Nahfeldes. Die selektive Abbildung unterschiedlicher elektrischer und magnetischer Feldkomponenten in Abhängigkeit vom Sondentyp wird demonstriert. Darüberhinaus wird die OPP-Erzeugung in einem Gitter auf dem Schaft einer Nahfeldspitze ausgenutzt, um propagierende OPPen im Apex zu konzentrieren. Ein weiterer Teil der Arbeit nutzt elektrische Feldüberhöhungen an scharfen Metallspitzen für die lokalisierte Erzeugung nichtlinearer optischer Signale. Die Beobachtung intensiver Multiphoton-Elektronenemission nach Femtosekundenanregung stellt ein zentrales Ergebnis dar. Dieser Prozess wird umfangreich charakterisiert und findet seine erste Anwendung in einer neuartigen Rastersondentechnik, in der die örtlich variierende Elektronenemission der Bildgebung dient.
This thesis contributes to the understanding of optical excitations in metallic nanostructures. In experiments on selected model structures, the dynamics of these excitations and their electromagnetic spatial modes are investigated with femtosecond temporal and nanometer spatial resolution, respectively. Angle- and time-resolved transmission experiments on metallic thin film gratings demonstrate the dominant role resonant surface plasmon polaritons (SPPs) play in the optical properties of such structures. The lifetimes of these excitations are determined, and it is shown that coherent couplings among SPP-resonances result in drastic lifetime modifications. The spatial SPP mode profiles are imaged using a custom-built near-field optical microscope. The experiments reveal a direct correlation between the spatial mode structure and the dynamics of different SPP resonances. These findings allow for an interpretation of the near-field optical image contrast in terms of the contributions of different vectorial components of the electromagnetic near-field. A selective imaging of different electric and magnetic field components is demonstrated for various types of near-field probes. Furthermore, the excitation of SPPs in periodic structures is employed in a novel type of near-field tip. The resonant excitation of SPPs in a nanofabricated grating on the shaft of a sharp metallic tip results in their concentration at the tip apex. The final part of the thesis highlights the importance of optical field enhancements for the local generation of nonlinear optical signals at the apex of sharp metallic tips. Specifically, the observation of intense multiphoton electron emission after femtosecond excitation is a major result. This process is thoroughly characterized, and a novel scanning microscopy application based on this effect is presented. In this technique, an image contrast with nanometer resolution arises from spatially varying electron emission rates.

49

Tatsis, A. "Hydraulic conveying of metallic platelets." Thesis, Imperial College London, 1987. http://hdl.handle.net/10044/1/46749.

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50

Hardin, Thomas J. 1988. "Kinetic metallic glass evolution model." Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/120206.

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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2018.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 213-227).
The structure of metallic glass controls its mechanical properties; this structure can be altered by thermomechanical processing. This manuscript presents a model for this structural evolution of metallic glass under thermal and mechanical stimuli. The foundation of this model is a potential energy landscape; this consists of three pieces: a function for the energy of any given stable state, a density of states function across the landscape, and a model for the energetic barriers between stable states. All three of these pieces are parameterized in terms of the configurational potential energy of the glass, which is split into isochoric and dilatative degrees of freedom. Under a thermal or mechanical stimulus, the glass traverses the potential energy landscape by way of isotropic relaxation or excitation events, and by shear transformations. The rates of these events are calculated using transition state theory. This model is first implemented in homogeneous form, treating the glass nanostructure as a statistical distribution; this implementation, while devoid of spatial detail, is nonetheless able to fit many of the experimental results on homogeneous flow previously in the literature. The second implementation of the model is in a mesoscale discrete shear transformation zone dynamics framework; this couples the model's rate equations to discrete points in a finite element model under realistic thermomechanical loading, and propagates the effects of local events via static elasticity. Emphasis is placed on efficient computer implementation of the new model's physics, improving on the previous state of the art with stiffness matrix factor caching and geometric multigrid methods. These numerical improvements produce a 200x speedup over previous algorithms, enable rapid simulations of glass with evolving elastic properties, and facilitate the first-ever metallic glass simulations of physical nanomechanical experiments with matching length and time scales.
by Thomas James Hardin.
Ph. D.

Dissertations / Theses on the topic 'Metalling'

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