Materials Literature
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Using atomistic pseudopotential wave functions we calculate the quasiparticle gap, the optical gap and the electron and hole addition energies of CdSe nanocrystals. We find that the quasiparticle gap and the addition energies depend strongly on the dielectric constant of the surrounding material, while the optical gap…
Small-angle X-ray scattering (SAXS), which determines the radius of gyration, R(g), and the pair distance distribution function, was used to investigate the conformational changes of calmodulin (CaM) on binding to an antagonist, trifluoperazine (TFP), with or without Ca(2+) in solution. We previously applied this SAXS…
The dynamic conductance of carbon nanotubes was investigated using the nonequilibrium Green's function formalism within the context of a tight-binding model. Specifically, we have studied the ac response of tubes of different helicities, both with and without defects, and an electronic heterojunction. Because of the i…
Gas-tube protector units are used in telecom network interface device boxes and central office switching gears to provide protection from lightning and alternating current power cross faults on the telecom network. Current gas discharge tube (GDT) protector units are unreliable from the standpoint of mean turn-on volt…
The strong influence of nuclear spins on resonant quantum tunneling in the molecular cluster Fe8 is demonstrated for the first time by comparing the relaxation rate of the standard Fe8 sample with two isotopic modified samples: (i) 56Fe is replaced by 57Fe, and (ii) a fraction of 1H is replaced by 2H. By using a recen…
Current and its noise in a ferromagnetic double tunnel barrier device with a small spacer particle were studied in the framework of the sequential tunneling approach. Analytical formulae were derived for electron tunneling through the spacer particle containing only a single energy level. It was shown that Coulomb int…
Granular materials react to shear stresses differently than do ordinary fluids. Rather than deforming uniformly, materials such as dry sand or cohesionless powders develop shear bands: narrow zones containing large relative particle motion leaving adjacent regions essentially rigid[1,2,3,4,5]. Since shear bands mark a…
We measured thermal conductivity $\ensuremath{\kappa}$, thermoelectric power $S$, and electric conductivity $\ensuremath{\sigma}$ of ${\mathrm{La}}_{5/8\ensuremath{-}x}{\mathrm{Pr}}_{x}{\mathrm{Ca}}_{3/8}{\mathrm{MnO}}_{3}$, showing an intricate interplay between metallic ferromagnetism (FM) and charge ordering (CO) i…
The oxygen-deficient double perovskite YBaCo2O5, containing corner-linked CoO5 square pyramids as principal building units, undergoes a paramagnetic to antiferromagnetic spin ordering at 330 K. This is accompanied by a tetragonal to orthorhombic distortion. Below 220 K orbital ordering and long-range Co(2+)/Co(3+) cha…
GaAs has been selectively grown in a hexagonally ordered array of nanometer-scale holes with a density as high as ∼1011/cm2 by metalorganic chemical vapor deposition. This array of holes was created using block copolymer lithography, in which a thin layer of diblock copolymer was used as an etching mask to make dense…
We have developed a process to fabricate well-aligned, patterned, carbon nanotube field emitters on glass substrates. The process consists of depositing and patterning a nickel-based metal line on the glass substrate followed by a bias-enhanced microwave plasma chemical vapor deposition to grow carbon nanotube emitter…
The effects of impurities and local structural defects on the conductance of metallic carbon nanotubes are calculated using an ab initio pseudopotential method within the Landauer formalism. Substitutionally doped boron or nitrogen produces quasibound impurity states of a definite parity and reduces the conductance by…
Using low-resistance electrical contacts, we have measured the intrinsic high-field transport properties of metallic single-wall carbon nanotubes. Individual nanotubes appear to be able to carry currents with a density exceeding 10(9) A/cm(2). As the bias voltage is increased, the conductance drops dramatically due to…
Abstract A comprehensive model has been developed for simulating the rates of general corrosion of selected metals in aqueous solutions. The model consists of a thermophysical and an electrochemical module. The thermophysical module is used to calculate the speciation of aqueous solutions and to obtain concentrations,…
Abstract This paper deals with the practical perspectives of corrosion inhibition in production operations. To this end examples of inhibition of sweet gas wells, wet gas pipelines and flowlines, and oil pipelines are discussed and challenges are identified. It is shown that a number of common problems can be avoided…
Abstract The effective use of both oxidizing and non-oxidizing biocides for control of MIC in cooling water systems was evaluated. A patented localized corrosion monitor was used to monitor changes in localized corrosion rates within laboratory scale and pilot cooling tower systems under various biocide treatment regi…
Abstract The partitioning of a corrosion inhibitor between the oil and water phases has a significant impact on inhibitor selection, treatment philosophy, and inhibitor transport. This work was undertaken to develop information on how inhibitor concentration varies with treatment rate and operational conditions. It wa…
Abstract Alkanolamine solutions removing acid gases such as CO2 and H2S from natural gas, synthetic gas or light hydrocarbons are often plagued not only by corrosion problems but also by fouling of heat exchange surface area and contact equipment. Corrosion due to amine heat stable salts and CO2 are of particular conc…
Abstract One of the challenges in the operation of gas wells with co-produced water is downhole and surface facility scale deposition. Scale deposition problems such as reduced tubing size are more likely when the produced water is very saline, and the pressure/temperatures changes are large. In addition to the common…
Abstract The key to a successful pipeline anti-corrosion program is an effective protective coating system comprised of proven, high-quality coating materials, consistently applied to exacting specifications. Mill applied fusion-bonded epoxy (FBE) has been, and continues to be, the coating of choice for many pipeline…