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Showing 1 to 15 of 15 for “"Chemical diffusion"”.
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Electromigration and chemical diffusion in titanium carbide
The ionic charge and lattice diffusion of carbon in titanium carbide have been investigated through studies of diffusion under the influences of kan applied dc-electric field and of a chemical potential. The electron microprobe was used to measure the diffusion concentration profiles. …
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Tracer and Chemical Diffusion in Silver - Silver Cadmium Diffusion Couples
Made available in DSpace on 2015-05-12T17:03:35Z (GMT). No. of bitstreams: 2 license.txt: 4848 bytes, checksum: 96035ab3f5e1c23cc7138a224ce498bd (MD5) 5801720.PDF: 3020772 bytes, checksum: 3380b0bd49456edcad316dbea1437c42 (MD5) Previous issue date: 1958
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Chemical diffusion of oxygen in yttrium barium(2) copper(3) oxygen(6+x)
… with a quantitative investigation of the chemical diffusion of oxygen in YBa$\sb2$Cu$\sb3$O$\sb{\rm 6+x}$. The research also investigates the optimization of crystal growth and the interrelationship between oxygen mobility and ferroelastic characteristics. Oxygen jump mechanisms in YBCO …
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A method for approximating and controlling the distributed parameter model of a MIMO chemical diffusion system
Chemical distribution is an important factor in many biological systems. Chemotaxis, the directed movement of an organism in response to chemical in its environment, is known to be a prominent driver in the directed growth of new blood vessels from pre-existing ones, a phenomenon called angiogesis. …
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The kinetics of liquid-liquid extraction of metals in a rotating diffusion cell. A rotating diffusion cell is used to study the rates of extraction of divalent transition metals by di-(2-ethylhexyl)-phosphoric acid and a sulphur analogue. A chemical-diffusion model describes the rate curves.
A rotating diffusion cell (RDC) has been used to study the kinetics of extraction of the transition metals cobalt (II), nickel (II), copper (II) and zinc (II) from sulphate solutions into either of two extractants held in n-heptane; di-(2-ethylhexyl) phosphoric acid (D2EHPA) or di-(2- ethylhexyl) …
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A thermogravimetric study of oxygen diffusion in YBa2Cu3O7-d
… presents a thermogravimetric study of oxygen diffusion in YBCO under isothermal and non-isothermal conditions and tries to reconcile the data available based on the results obtained and taking into account the factors that may have affected the data presented by other groups, such as the …
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Development of a hydrogel-based biocompatible platform for studying metabolic interactions between algae and bacteria
… cycling in ocean ecosystems. To date, studying chemical exchange between these microbial species based on molecular diffusion processes has been challenging due to a lack of an appropriate co-culture system. In this thesis, a hydrogel-based biocompatible platform is proposed to study the …
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Phase behavior and phase transformation kinetics during electrochemical cycling of lithium transition metal olivine compounds
… the rate capability of olivines purely to chemical diffusion limitations. Many efforts have been devoted to improving the conductivity and the rate performance of LiFePO4 cathodes. Since this class of olivines undergoes a first-order phase transition upon electrochemical cycling, in order …
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The effects of dopants and complexions on grain boundary diffusion and fracture toughness in α-Al2O3
… of alumina that depend on its grain boundaries; diffusional transport and mechanical fracture. Previously enigmatic grain boundary behavior in alumina, such as abnormal grain growth, were found to derive from chemically or thermally induced grain boundary phase transitions or complexion …
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Gravimetric, neutron scattering and computational studies of the sorption and diffusion of gases in zeolites
… as the concentration dependence and ratio of the diffusion coefficients are observed. This technique provides a valuable bridge between traditional Molecular Dynamics and Metropolis et al algorithm Monte Carlo simulations as the evolution of the system can be followed over much longer timescales …
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An electrochemical investigation of the chemical diffusivity in liquid metal alloys
… of these liquid alloys, in particular the chemical diffusivity, must be known accurately so that it can be used as input in computational simulations to avoid the nucleation of any solids. Unfortunately, the dominant experimental methods for measuring diffusion in liquid metals today are …
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Oxygen Transport Membrane Reactors for Oxy-Fuel Combustion and Carbon Capture Purposes
… ionic and electronic conductive properties and chemical stability. SSC’s oxygen ion diffusivity is investigated using a conductivity relaxation technique and thermogravimetric analysis. Material properties such as chemical structure, morphology, and ionic and electronic conductivity are examined …
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Water in the Earth’s Interior: Thermodynamics and kinetics of hydrogen incorporation in olivine and wadsleyite
(1) Hydrogen diffusion in olivine The kinetics of hydration of dry single crystals of San Carlos olivine was determined by performing experiments under water-saturated conditions. The experiments were performed at 1.5 GPa, 1000°C for 5 hours in a piston cylinder apparatus, or at 0.2 GPa, 900°C, for …
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Transient Liquid Phase Bonding of Titanium-, Iron- and Nickel- Based Alloys
… work commercially pure Ti, Fe and Ni were diffusion bonded using commercially available interlayer materials. Commercially pure Ti (Ti-grade 2) has been diffusion bonded using silver and copper interlayers and without any interlayer. With a silver (Ag) interlayer, different intermetallics …
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Computational Simulation of Chloride-Induced Corrosion Damage in Prestressed Concrete Bridge Girders
… a phenomenological description of the electrochemical reaction kinetics, generation of expansive corrosion products, and subsequent development of tensile stresses and cracking in the surrounding concrete. The impact of cracking on the chloride and moisture transport mechanisms is also taken …