Cell Phone Detection Techniques

A team composed of Rick Pratt, Dave Puczyki, Kyle Bunch, Ryan Slaugh, Morris Good, and Doug McMakin teamed together to attempt to exploit cellular telephone features and detect if a person was carrying a cellular telephone into a Limited Area. The cell phone’s electromagnetic properties were measured, analyzed, and tested in over 10 different ways to determine if an exploitable signature exists. The method that appears to have the most potential for success without adding an external tag is to measure the RF spectrum, not in the cell phone band, but between 240 and 400MHz. Figures 1- 7 show the detected signal levels from cell phones from three different manufacturers

Enhanced gas permeation through graphene nanocomposites

The use of membranes for gas permeation and phase separation offers many distinct advantages over other more energy-dependent processes. The operational efficiencies of these membranes rely heavily on high gas permeability. Here, we report membranes with significantly increased permeability without a considerable decrease in mechanical strength or selectivity, synthesized from a polymer nanocomposite that incorporates graphene and polydimethylsiloxane (PDMS). These graphene–PDMS nanocomposite membranes were able to enhance the gas permeation of N₂, CO₂, Ar, and CH₄ in reference to pristine PDMS membranes. This is achieved by creating interfacial voids between the graphene flakes and polymer chains, which increases the fractional free volume within the nanocomposites, giving rise to an increase in permeation. An optimal loading of graphene was found to be 0.25 wt%, while greater loading created agglomeration of the graphene flakes, hence reducing the effective surface area. We present the enhancements that the membranes can provide to sensing and phase separation applications. We show that these nanocomposites are near transparent to CO₂ gas molecules in sensing measurements. This study offers a new area of research for graphene-based nanocomposites