Electric field measuring and display system

An apparatus is described for monitoring the electric fields of cloud formations within a particular area. It utilizes capacitor plates that are alternately shielded from the clouds for generating an alternating signal corresponding to the intensity of the electric field of the clouds. A synchronizing signal is produced for controlling sampling of the alternating signal. Such samplings are fed through a filter and converted by an analogue to digital converter into digital form and subsequently fed to a transmitter for transmission to the control station for recording

Measuring the electric field of a cloud

Network of electric field measuring stations has been developed to assess lightning hazard of charged clouds. Sensor data are digitized and transmitted to central processing area for display

Direct and indirect impacts of shoreline development on shallow-water benthic communities in a depauperate estuarine system

Modification of natural coastlines is prevalent as human coastal populations swell and effects of global climate change become clearer. We investigated effects of shoreline hardening and environmental factors on benthic infauna and trophic structure in the Patuxent River, Maryland, a stressed mesohaline Chesapeake Bay tributary. We characterized differences in density, diversity, biomass, and trophic structure for large (\u3e3 mm) and small (\u3e500 μm) infauna adjacent to natural marsh, riprap, and bulkhead (i.e., seawall) shores throughout the river. Akaike information criterion model comparisons were used to assess the evidence for differences in benthic infaunal structure using primary (shoreline type) and secondary (e.g., sediment grain size, predator abundance) variables. There was strong evidence for secondary factors to explain reduced biomass of infauna adjacent to developed shorelines. For large infauna, evidence suggested that shorelines with riprap had reduced diversity, and with bulkhead had increased diversity. Increased wave energy and chlorophyll-a were associated with high densities for both size fractions riprap shorelines. Trends suggested high biomass and more carnivores, omnivores, and deposit feeders adjacent to natural marshes, compared to low biomass and more filter feeders at developed shorelines. While similar studies in lower Chesapeake Bay systems have shown clear effects of shoreline type on benthic communities, the extensive development in the Patuxent River may contribute to larger-scale stress, yet some shoreline-specific effects were detected. Non-parametric tests revealed differences in infaunal communities by shoreline type and river zone. Thus, the benthic community in this estuary is driven by local shoreline effects, as well as large-scale physical and biotic factors

Effect of surrounding environment on atomic structure and equilibrium shape of growing nanocrystals: gold in/on SiO2

We report on the equilibrium shape and atomic structure of thermally-processed Au nanocrystals (NCs) as determined by high resolution transmission electron microscopy (TEM). The NCs were either deposited on SiO2surface or embedded in SiO2layer. Quantitative data on the NCs surface free energy were obtained via the inverse Wulff construction. Nanocrystals inside the SiO2layer are defect-free and maintain a symmetrical equilibrium shape during the growth. Nanocrystals on SiO2surface exhibit asymmetrical equilibrium shape that is characterized by the introduction of twins and more complex atomic defects above a critical size. The observed differences in the equilibrium shape and atomic structure evolution of growing NCs in and on SiO2is explained in terms of evolution in isotropic/anisotropic environment making the surface free energy function angular and/or radial symmetric/asymmetric affecting the rotational/translational invariance of the surface stress tensor

Controlled Decoration of Single-Walled Carbon Nanotubes with Pd Nanocubes

Although there have been many reports of nanoparticle-decorated single-walled carbon nanotubes (SWCNTs), the morphology of the resulting nanoparticles has lacked consistency and control. The present work demonstrates a process for decorating SWCNTs with Pd nanoparticles that have a tendency toward a selective and distinct cubic shape. SWCNTs were synthesized from an embedded catalyst in a porous anodic alumina (PAA) template. A single galvanostatic electrodeposition created Pd nanowires that contacted the SWCNTs within the pores and Pd nanoparticles that decorated the SWCNTs above the surface of the PAA. A distinct change in potential was observed as nanoparticles nucleated on the SWCNTs. The effects of current density and deposition time on the morphology of the nanoparticles were studied. Optimal deposition parameters yielded Pd nanocubes with smooth and flat facets. The electrochemical response and resulting nanocubic deposits provide insights into the difference in electrochemistry between metallic and semiconducting SWCNTs that are consistent with a disparity in the electron-transfer kinetics. Obtaining Pd nanoparticles of consistent shape that are electrically addressed by SWCNTs provides an improved structure for a variety of nanoparticle applications

WO3-x nanorods synthesized on a thermal hot plate

10.1021/jp074569zJournal of Physical Chemistry C1114617193-1719