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We present the modification of the orbits of chi Draconis and HD 184467, and a completely new orbit for HD 198084, including data taken at the Center for High Angular Resolution Astronomy (CHARA) Array. These data were obtained using a modification of the technique of separated fringe packets (SFPs). The accuracy of the SFP data surpasses that of data taken by speckle, but the technique is much more time and labor intensive. Additionally, using SFPs with the CHARA Array, it is possible to obtain separations below the detection range of speckle interferometry (greater than or equal to 30 mas) above the range in "classic" long-baseline interferometry where fringes from a binary overlap are no longer separated (less than or equal to 10 mas). Using spectroscopic binary systems with published speckle orbits, we are able to test our new measurements against their ephemerides to calibrate the method as well as produce entirely new orbits for systems with no current astrometric observations., Published in the Astronomical Journal, v139 p2308-2318, June 2010.

In recent years, the area of nanocomposites has received considerable attention with the expectation that nanotechnology can leas to lighter, better materials for engineering applications. For example, the attractiveness of polymer-clay nanocomposites resides in the potential of adding infinitesimally small clay platelets, to improve mechanical, thermal, barrier, and flame-retardant properties without increasing the specific gravity or reducing the transparency of the nanocomposite relative to the base material. One of the major roadblocks in the wider use of nanoclay platelets in thermoset and thermoplastic polymeric materials has been the poor dispersion of polar clay into a non-polar polymer matrix. It is believed that consistent improvements in strength and modulus of clay loaded polymeric system can be achieved by minimizing clay aggregation, promoting the formation of chemical bonds between polymer and clay and achieving exfoliation of clay. The other major problem that the nanocomposite community faces is the reduction in fracture toughness and failure strain of the nanocomposites due to the addition of clay.

Nanocomposites are a relatively new class of materials obtained by dispersing montmorillonite clay in a polymer matrix. Evidences from literature suggest that clay platelet dispersion during nanocomposite preparation and clay-matrix adhesion are major technical issues that need to be addressed in order to achieve the desired property enhancements in polymer-clay hybrid nanocomposites. We have studied the interaction of the organically functionalized clay with the epoxy resin by including along the chain structure functional groups that will facilitate interaction with the resin. Through conventional routes, functional molecules have been synthesized and deposited on to the clay surface. Both the functionalized and nonfunctionalized clay has been analyzed using thermal gravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FTIR). The exfoliation of nanoclay platelets in amine cured epoxy system has been studied using X-ray diffraction (XRD) and transmission electron microscopy (TEM)., Pub in: Materials Research Society Symposium Proceedings, Volume 703. Prepared in collaboration with the National Institute of Standards and Technology, Polymer Division, Gaithersburg, MD. This article is from ADA401575 Nanophase and Nanocomposite Materials IV held in Boston, Massachusetts on November 26-29, 2001

Characterization of heterogeneous phases in polymers and hydrophilic regions in coatings have been the subject of AFOSR funded research project. Although hydrophilic regions occupy only a small fraction of the coating film volume. the hydrophilic regions control the corrosion protection performance of a polymer coating. At present the progress in the characterization of hydrophilic regions in coatings is very limited because of the lack of suitable analytical technique that can provide nanoscale lateral information. We mapped mechanical and chemical heterogeneities in model polymer coating compounds and characterized degradation susceptible regions in commercial coatings at nanoscale level. Nanoindentation procedure in combination with TMAFM was used to identify soft and hard regions in a heterogeneous model coating compound. To map chemically heterogeneous regions in model systems. we developed AFM/chemical modification approach. An effort was made to relate the microstructure of polymer coating film to the changes that occur to film upon environmental exposure and relate the changes to the chemistry of degraded compound. The material leached out from the coating during immersion was characterized. The leached material was mostly unreacted starting monomers and oligomers. They probably represent the degradation-susceptible regions (hydrophilic regions) of coating film. With the use of an atomic force microscope (AFM). which provides nanometer spatial resolution and angstrom depth resolution, we recently observed the progression of pathway formation in polyester and acrylic-polyurethane coatings, common protective materials for industrial, automobile, and aerospace applications. FTIR results in combination with AFM results (pit formation) support the observation that the extent of degradation of polyurethane coating film is much larger for samples exposed to UV at high relative humidities compared to no UV and high relative humidity.