We present a new architecture for a programmable dispersion matrix for optical beamforming. A 2-channel prototype is constructed to demonstrate beam steering for angles of ± 70 in the receive/transmit mode in RF 0.1-1 GHz frequency range.

Fitting multivariate α-stable distributions to data is still not feasible in higher dimensions since the (non-parametric) spectral measure of the characteristic function is extremely difficult to estimate in dimensions higher than 2. This was shown by Chen and Rachev (1995) and Nolan, Panorska and McCulloch (1996). α-stable sub-Gaussian distributions are a particular (parametric) subclass of th...

Carbon nanotubes (CNTs ) are considered to be one of the novel reinforcement for developing advanced nanocomposites due to their outstanding thermo-mechanical properties. Multi-walled carbon nanotubes (MWCNTs ) are developed by arc discharge method. To enhance the dispersion of CNTs in polymer matrix, CNTs are modified with chemical treatment and processed by ultrasonication process. Surface ch...

Preparation of E-glass/waterborne epoxy prepregs containing natural nanoclay and properties of their composites are presented. Prepregs were prepared by wetting randomly oriented, chopped glass fiber preforms with aqueous dispersion of EpiRez 3522-W-60 resin, dicyandiamide, 2-methylimidazole and natural nanoclay (Cloisite Naþ). The nanoclay content of the aqueous dispersion was adjusted to yiel...

The authors’ research group has previously developed a novel method for the fabrication of silica/perfluoropolymer nanocomposites, wherein nano-sized silica particles without surface modification were dispersed uniformly through breakdown of loosely packed agglomerates of silica nanoparticles with low fracture strength in a polymer melt during direct melt-compounding. The method consists of two...

Montmorillonite (MMT) clay mineral is widely used as filler for several organic coatings. Its activity is increased by exfoliation via chemical modification to produce nanomaterials. In the present work, the modification of MMT to form nanogel composites is proposed to increase the dispersion of MMT into epoxy matrices used to fill cracks and holes produced by the curing exotherms of epoxy resi...

This work aims to develop and compare two types of conductive, polymer-based coatings via a dip coating process. The first type of coatings was made by dispersing and incorporating carbon black (CB) nanoparticles in a poly(methyl methacrylate) (PMMA) solution followed by dip coating. The CB content and dipping parameters were varied to explore their effects on the particle dispersion, coating t...

Using a rigorous and vector multipole method, we compute both losses and dispersion properties of microstructured optical fibers with finite cross sections. We restrict our study to triangular lattices of air-hole inclusions in a silica matrix, taking into account material dispersion. The fiber core is modeled by a missing inclusion. The influence of pitch, hole diameter, and number of hole rin...

Cross-linking of the cubic silicate building block, Si8O20 with vanadyl chloride leads to porous solids in which a homogeneous dispersion of isolated vanadyl groups is maintained throughout the matrix even at high loadings of vanadium.

Polymer nanocomposites have attracted great interest over many years, because of the enhanced properties exhibited by such systems. However, it is only recently that the electrical characteristics of this class of material have begun to be studied in detail. Whenever fillers are added to a host polymer matrix, dispersion is of critical importance since, while a well dispersed nanophase may be b...