Analysis of the Adsorption of Alkanes on High Surface Area Cellulose by Inverse Gas Chromatography

The adsorption characteristics of alkanes on high surface area cellulose were investigated by inverse gas chromatography.

The enthalpy and entropy of adsorption of alkanes on the solvent exchanged cellulose were greater than the values on non-porous cellulose. The difference in the heats of adsorption of alkanes between the non-porous and the solvent exchanged cellulose was greater for larger molecules indicating stronger interaction for the higher alkanes in the pore structure. For n-hexane the differences in enthalpy and entropy of adsorption were 17 kJ/mole and 52 J/mole K, respectively. The London component of the surface free energy of adsorption was 116 mN/m for the solvent exchanged cellulose.     

Effect of the Shutdown of a Coal-Fired Power Plant on Urban Ultrafine Particles and Other Pollutants

Ultrafine particle (UFP) monitoring over the size range of 10–500 nm has been ongoing in Rochester, New York, since November 2001. A nearby large coal-fired power plant (CFPP) was shut down in the spring of 2008 for conversion to natural gas combustion. This shutdown resulted in a reduction in observed concentrations of UFP number and other pollutants. In this study, positive matrix factorization (PMF) model and conditional probability function (CPF) were used to elicit the CFPP source information based on 2005–2010 hourly concentration data of particles and gaseous species and meteorological variables. Five factors were identified, i.e., nucleation, regional transport, traffic, CFPP, and O₃-rich secondary aerosol that influenced the measured pollution levels. The average 10–50 nm, 50–100 nm, and 100–500 nm particle number concentrations decreased 49.8%, 51.9%, and 52.9% from 2007 to 2008, respectively. The annual average SO₂, CO, and PM_2.5 concentrations also decreased by 64.1%, 39.6%, and 45.6% from 2007 to 2008, respectively. The largest reductions of 10–50 nm particles, CO, and SO₂ concentrations between 2007 and 2009 were observed with northerly winds. These changes were clearly attributed to the shutdown of the large CFPP in the study area.     

Increasing coverage to improve detection of network and host anomalies

For intrusion detection, the LERAD algorithm learns a succinct set of comprehensible rules for detecting anomalies, which could be novel attacks. LERAD validates the learned rules on a separate held-out validation set and removes rules that cause false alarms. However, removing rules with possible high coverage can lead to missed detections. We propose three techniques for increasing coverage—Weighting, Replacement and Hybrid. Weighting retains previously pruned rules and associate weights to them. Replacement, on the other hand, substitutes pruned rules with other candidate rules to ensure high coverage. We also present a Hybrid approach that selects between the two techniques based on training data coverage. Empirical results from seven data sets indicate that, for LERAD, increasing coverage by Weighting, Replacement and Hybrid detects more attacks than Pruning with minimal computational overhead.     

On adsorption of aluminium and methyl groups on silica for TMA/H<Subscript>2</Subscript>O process in atomic layer deposition of aluminium oxide nano layers

A detailed chemisorption mechanism is proposed for the atomic layer deposition (ALD) of aluminium oxide nano layers using trimethyl aluminum (TMA) and water as precursors. Six possible chemisorption mechanisms, complete ligand exchange, partial ligand exchange, simple dissociation, complete dissociation via ligand exchange, complete dissociation and association, are proposed and related parameters like ligand to metal ratio (L/M), concentrations of metal atoms and methyl groups adsorbed are calculated and compared against reported values. The maximum number of methyl groups that can get attached on the surface is calculated in a different way which yields a more realistic value of 6·25 per nm² substrate area. The dependence of the number of metal atoms adsorbed on OH concentration is explained clearly. It is proposed that a combination of complete ligand exchange and complete dissociation is the most probable chemisorption mechanism taking place at various OH concentrations.     

Robust Multilayer Control for Enhanced Wireless Telemedical Video Streaming

M-health is an emerging area of research and one of the key challenges in future research in this area is medical video streaming over wireless channels. Contrasting requirements of almost lossless compression and low available bandwidth have to be tackled in medical quality video streaming in ultrasound and radiology applications. On one side, compression techniques need to be conservative, in order to avoid removing perceptively important information; on the other side, error resilience and correction should be provided, with the constraint of a limited bandwidth. A quality-driven, network-aware approach for joint source and channel coding based on a controller structure specifically designed for enhanced video streaming in a robotic teleultrasonography system is presented. The designed application based on robotic teleultrasonography is described and the proposed method is simulated in a wireless environment in two different scenarios; the video quality improvement achievable through the proposed scheme in such an application is remarkable, resulting in a peak signal-to-noise ratio (PSNR) improvement of more than 4 dB in both scenarios.     

Modeling Mamala Bay Outfall Plumes.?II: Far Field

The far-field behavior and water quality impacts of the Sand Island, Hawaii, ocean outfall plume were predicted using two models, a statistical short-term model and a long-term model. The short-term model is coupled to a near-field model and uses measurements obtained from Acoustic Doppler Current Profilers. It predicted that the variable currents would cause the visitation frequency of the plume to decrease rapidly with distance. The long-term model predicted that flushing, horizontal diffusion, and decay would result in high dilutions with no significant buildup of contaminants. The frequencies of exceedence of various coliform densities were predicted to decrease rapidly with distance so that bacterial water quality standards should be satisfied very close to the diffuser. Any outfall impacts on the beaches should be very small, and other nonsewage sources are likely to contribute higher levels of bacteria. The effects of treatment upgrades on shoreline water quality will therefore probably be negligible. The results indicate that worst-case conditions are extremely improbable, and their use could lead to overly conservative outfall designs and treatment levels.     

Effect of NiO on the Phase Stability and Microstructure of Yttria-Stabilized Zirconia

Nickel oxide (NiO) was screen printed onto the surfaces of 3 and 8 mol% yttria-stabilized zirconia (YSZ) dense pre-fired substrates and then heat treated at temperatures from 1350° to 1550°C. The effect of NiO was dependent on the yttria content of the substrate. In 3 mol% YSZ, it was found to alter the phase composition from predominantly tetragonal with a small amount of cubic phase to one consisting of approximately equal amounts of cubic and monoclinic phase. The cubic grains were much larger than the monoclinic ones and contained more nickel. Furthermore, nickel was observed to migrate through the thickness of the tile, a distance of approximately 200 μm. In the 8 mol% YSZ substrates, the phase composition was unaltered, although large grains developed under the printed NiO layer and the nickel migration was confined to the extent of these large grains.     

A survey of partial differential equations in geometric design

Computer-aided geometric design is an area where the improvement of surface generation techniques is an everlasting demand, since faster and more accurate geometric models are required. Traditional methods for generating surfaces were initially mainly based upon interpolation algorithms. Recently, partial differential equations (PDE) were introduced as a valuable tool for geometric modelling, since they offer a number of features from which these areas can benefit. This work summarizes the uses given to PDE surfaces as a surface generation technique together with some other applications to computer graphics.