The Annual Black Start Service Selection Analysis of ERCOT Grid

This paper evaluates ERCOT's existing annual Black Start service selection analysis and subsequently presents novel selection procedures. ERCOT procures Black Start resources annually through a competitive process. It selects and awards contracts to qualifying resources after completing a Black Start unit selection analysis, which selects a group of Black Start resources that meet a set of system selection criteria consisting of system reliability and minimum cost parameters. A current analysis methodology exists, but due to its inherent limitations, it is very labor intensive. Further analysis methodology development is performed to streamline the selection process, enable additional functions, reduce the manual intervention of personnel, and overall to improve the selection analysis. This paper analyzes the current Black Start automatic program analysis, and proposes new methodologies, programming improvements, and enhanced user ability.     

Microcellular and nanocellular solid-state polyetherimide (PEI) foams using sub-critical carbon dioxide II. Tensile and impact properties

Microcellular foams, closed-cell polymer foams with cells of order 10 μm, have been studied for over two decades. These foams have shown significant improvements in mechanical properties, such as strength-to-weight ratio, over conventional foams with cells on the order of 1 mm. Will an additional 100-fold reduction in cell size yield further improvement in properties? Here we answer this question in the solid-state PEI-CO₂ system, a unique gas-polymer system in which cellular structures can be created throughout the polymer volume at either micro or nano scales. The tensile and impact behaviors of microcellular (cells in 2-5 μm range) and nanocellular (cells in the 50-100 nm range) structures are experimentally compared for foams with relative densities, to that of the starting solid, in the range of 0.75-0.90. We found that nanofoams show a significantly higher strain to failure, resulting in an improvement in the modulus of toughness by up to 350% compared to microcellular foams. Falling weight impact tests show evidence of a brittle-to-ductile transition in nanofoams resulting in impact energies that are up to 600% higher compared to microcellular foams. These results point to the promise of nanofoams as an important new class of materials.     

Gas Phase Initial Oxidation of Incoloy 800 Surfaces

The surface oxidation of Incoloy 800 was studied using dilute O₂ gas at temperatures of 300 °C. Samples with two differing grain sizes were studied using time-of flight secondary ion mass spectrometry (ToF–SIMS) and X-ray photoelectron spectroscopy (XPS) as primary analysis tools. A multi-layered oxide film was detected and was composed of an exterior gamma-Fe₂O₃ with a Cr₂O₃ layer at the oxide–metal interface also containing significant concentrations of NiCr₂O₄. Minor concentrations of another spinel oxide, NiFe₂O₄ were distributed throughout the film. The kinetics of oxidation growth was found to follow a direct logarithmic relationship for both grain sizes, suggesting that the oxide would be a suitably protective. Very small oxide nodules formed at later stages, particularly for the small grained samples. A protocol for assessment of XPS spectral envelopes is advanced. The method measures the percent residual intensities remaining after spectral subtraction of reference spectra and appears to be an effective means for screening of possible components.     

Optimized excitation energy transfer in a three-dye luminescent solar concentrator

The spectral range of sunlight absorbed by a luminescent solar concentrator (LSC) is increased by using multiple dyes. Absorption, fluorescence, and fluorescence excitation spectra, and relative light output are reported for LSCs made with one, two, or three BODIPY dyes in a thin polymer layer on glass. Losses caused by multiple emission and reabsorption events are minimized by optimizing resonance excitation energy transfer between dyes. Increases in the outputs from the multiple-dye LSCs are directly proportional to increases in the number of photons absorbed. The output of the three-dye LSC is 45–170% higher than those of the single-dye LSCs.     

Inattention as a key predictor of tobacco use in adolescence.

The authors examined the prediction from inattention to tobacco use among 2 cohorts (ages 7 and 13) of a community sample followed to young adulthood. Changes in self-reported tobacco use were tested with marginal transitional regression models, using parent and teacher ratings of inattention, hyperactivity-impulsivity, and other psychopathology, along with other factors, as predictors. Inattention, but not hyperactivity-impulsivity, significantly predicted adolescent tobacco use and young adult daily tobacco use. Peer substance use, parental substance use, and conduct disorder also predicted increases in tobacco use. African American ethnicity was strongly protective against later tobacco use. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mu and alpha EEG rhythms during the arrest reaction in microgravity

Mu and alpha oscillations (8–12 Hz) are the most prominent electroencephalographic rhythms observed in awake, relaxed subjects. Different cortical sources may participate in these oscillations and appear to be modulated by the sensorimotor context and functional demands. In microgravity, the marked reduction in multimodal graviceptive inputs to cortical networks participating in the representation of space could be expected to affect these spontaneous rhythms. Here, we report the results of an experiment conducted over the course of 3 space flights, in which we quantified the power of the mu and alpha rhythms in relation to the arrest reaction (i.e. in 2 distinct physiological states: eyes open and eyes closed). We observed that the power of the spontaneous mu and alpha rhythms recorded in the eyesclosed state in the sensorimotor areas (mu rhythm) and in the parieto-occipital cortex (alpha rhythm) increased in microgravity. The suppression coefficient produced by eye-opening/ closure state transition also increased in microgravity. These results are discussed in terms of current theories on the source and the physiological significance of these EEG rhythms.