Materials Literature
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In the present study, the processing and the mechanical properties of new thermoset nanocomposites prepared from aqueous suspensions of microcrystalline cellulose fillers and epoxy are described. The nature of cellulose fibers, which display a large aspect ratio and the ability to associate by means of H-bonds implies…
The connection between hysteresis and thermal relaxation in magnetic materials is studied from both the experimental and the theoretical viewpoint. Hysteresis and viscosity effects are measured in Finemet-type nanocrystalline materials above the Curie temperature of the amorphous phase, where the system consists of fe…
The magnetic properties of ${\mathrm{Li}}_{x}{\mathrm{Ni}}_{1\ensuremath{-}x}\mathrm{O}$ compounds with x ranging between 0.4 and 0.49 are investigated. Magnetization and ac susceptibility measured at temperatures between 2 K and 300 K reveal a high sensitivity to x, the excess lithium concentration. We introduce a pe…
Using first-principles calculations based on a variational density functional perturbation theory, we investigate the lattice dynamics of solid solutions of barium and strontium titanates. Averaging the information available for the related pure compounds yields results equivalent to those obtained within the virtual…
A summary of the work recently carried out on the morphotropic phase boundary (MPB) of PZT is presented. By means of x-ray powder diffraction on ceramic samples of excellent quality, the MPB has been successfully characterized by changing temperature in a series of closely spaced compositions. As a result, an unexpect…
The insulating state of matter is characterized by the excitation spectrum, but also by qualitative features of the electronic ground state. The insulating ground wavefunction in fact: (i) displays vanishing dc conductivity; (ii) sustains macroscopic polarization; and (iii) is localized. The idea that the insulating s…
The ppk gene encodes polyphosphate kinase (PPK), the principal enzyme in many bacteria responsible for the synthesis of inorganic polyphosphate (polyP) from ATP. A null mutation in the ppk gene of six bacterial pathogens renders them greatly impaired in motility on semisolid agar plates; this defect can be corrected b…
Most immiscible polymer blends are produced by melt compounding in extruders. The melting and mixing process can generate morphologies ranging from disperse drops to fibers to lamella to cocontinuous structures. Controlling these morphologies is critical to performance of the final blend. This paper reviews recent res…
A study of the exposure of SiC at 1200°C and high water‐vapor pressures (1.5 atm) has shown SiC recession rates that exceed what is predicted based on parabolic oxidation at water‐vapor pressures of less than or equal to ∼1 atm. After exposure to these conditions, distinct silica‐scale structures are observed; thick,…
The heats of combustion for 49 commercial and developmental polymers of known chemical structure were determined using an oxygen bomb calorimeter according to standard methods. The experimental results were compared with thermochemical calculations of the net heat of combustion from oxygen consumption and the gross he…
Abstract. We study the structural and thermodynamic properties of a model of point particles interacting by means of a Gaussian pair potential first introduced by Stillinger (Stillinger F H 1976 J. Chem. Phys. 65 3968). By employing integral equation theories for the fluid state and comparing with Monte Carlo simulati…
The columnar mesomorphism of triphenylene-, phthalocyanine-, tetraazaporphyrin- and porphyrin-based compounds is briefly reviewed and the potential use of this particular supramolecular structure for charge-conducting devices is discussed. Suitably substituted triphenylenes exhibit ideal material properties for photoc…
This paper proposes a new digital algorithm for the implementation of the fixed-frequency adaptive hysteresis current control for voltage-source inverters. The key features of the new algorithm are the minimization of the analog external circuitry, the capability to automatically compensate for the inverter deadtime e…
A simple and efficient methodology has been established for the selective synthesis of anatase and rutile as well as their mixtures with various precursors using ultrasound irradiation; the products, the particle sizes of which are nanometric (<9 nm), are dependent both upon the reaction temperature and the precursor…
We have developed Tersoff potential parameters for boron in order to simulate cubic boron carbonitride systems by molecular dynamics. Combined with parameters for C and N available from the literature, our parameters are shown to reproduce the lattice parameters and bulk moduli of boron nitride and boron carbonitride…
Poly(DL-lactide-co-glycolide) (PLGA)/polyethylene glycol (PEG) microspheres are one modality of controlled delivery of biologically active molecules that would further the development of engineered tissues. As a possible mechanism to stimulate angiogenesis within an engineered tissue, vascular endothelial growth facto…
Uniformly dispersed amorphous nanoparticles of magnetite in polyvinyl alcohol have been obtained by ultrasound radiation. The properties of the as-prepared composite material were characterized by various analytical methods. We have found that the magnetite particles that were 12–20 nm in diameter were very well dispe…
The overview of the literature for a 25-year period on the combustion and fire-retardant performance of major commercial aliphatic nylons is presented. It is shown that aliphatic nylons are relatively easily ignitable materials which support combustion and are therefore required to be fire retarded for some applicatio…
Zinc self-diffusion was measured in single crystal zinc oxide using nonradioactive Zn70 as the tracer isotope and secondary ion mass spectrometry for data collection. Crystal mass was closely monitored to measure ZnO evaporation. Diffusion coefficients were isotropic with an activation energy of 372 kJ/mol. Zinc self-…
Spinel and Perovskite Functional Layers Between Plansee Metallic Interconnect (Cr‐5 wt % Fe‐1 wt % Y 2 O 3) and Ceramic ( La0.85Sr0.15 ) 0.91MnO3 Cathode Materials for Solid Oxide Fuel Cells, Larring, Yngve, Norby, Truls