Formation of metal-cyanide complexes in deliquescent airborne particles: a new possible sink for HCN in urban environments

Hydrogen cyanide is a ubiquitous gas in the atmosphere and a biomass burning tracer. Reactive gasses can be adsorbed onto aerosol particles where they can promote heterogeneous chemistry. In the present study, we report for the first time on the measurement and speciation of cyanides in atmospheric aerosol. Filter samples were collected at an urban background site in the city center of Padua (Italy), extracted and analyzed with headspace gas chromatography and nitrogen-phosphorous detection. The results showed that strongly bound cyanides were present in all aerosol samples at a concentration ranging between 0.3 and 6.5 ng/m3 in the PM2.5 fraction. The concentration of cyanides strongly correlates with concentration of total carbon and metals associated with combustion sources. The results obtained bring evidence that hydrogen cyanide can be adsorbed onto aerosol liquid water and can react with metal ions to form stable metal-cyanide complexes

Incorporating energy conservation techniques in the operation of existing LeRC R and D facilities

A general discussion of various methods which can be used to reduce energy consumption is presented. A very brief description of Lewis Research Center facilities is given and the energy reduction methods are discussed relative to them. Some specific examples (ie; automated equipment and data systems) of the implementation of the energy reduction methods are included

Measurement of total hydrocarbon emissions with MEMS using a portable FID and a novel exhaust flow meter

The objective of this study was to evaluate tools for in-field, on-board engine emissions measurements, namely, a Signal Model 3030PM hydrocarbon analyzer and McCrometer\u27s V-Cone flow meter. The Signal Model 3030PM analyzer uses a heated flame ionizing detection scheme to measure hydrocarbons. The V-Cone is an obstructive, differential pressure flow meter that reshapes the flow profile, therefore conditioning the flow.;The Signal Model 3030PM analyzer was found to perform as well or better than the HC analyzers currently used in the FTP test cell. Besides the portability feature, the Signal Model 3030PM demonstrated better response, being able to capture the high and low concentrations better.;When compared with an AnnubarRTM flow meter, the V-Cone measured consistently higher than the AnnubarRTM for the flow rates and this translated into higher mass rates. After recalculating the V-Cone values using the correction factor, the V-Cone had integrated errors of less than 5% for transient tests and 10% for steady state tests when compared to the Annubar

Investigation into pedestrian exposure to near-tailpipe exhaust emissions

Inhalation of particulate matter is known to cause negative human health effects. Consequently, regulatory agencies have set regulations and standards that limit the maximum concentrations to which persons may be exposed and the maximum concentrations allowed in the ambient air. However, these standards consider steady exposure over large spatial and time scales. Because many vehicles\u27 exhaust systems direct exhaust towards sidewalks, pedestrians in close proximity to a roadway may experience events where for brief periods of time particulate matter concentrations are high enough to cause acute health effects. In order to quantify these exposure events, instruments which measure specific exhaust pollutant concentrations were placed near a roadway and connected to the mouth of a mannequin used as a pedestrian surrogate. A representative estimate of the exposure potentially experienced by pedestrians was obtained by measuring concentrations at the mannequin\u27s mouth during drive-by events with a diesel truck and a gasoline truck. Breathing rates were then multiplied by the measured concentrations to determine the mass of pollutant inhaled daily and per breath. The highest concentrations observed with the diesel test vehicle were 2.2 million particles/cc and 1400 mug/m 3. The average concentration of particulate matter measured over the duration of a single drive-by test was observed to reach the same order of magnitude as the low concentrations used in human clinical studies which are known to cause acute health effects. It was also observed that concentrations of particulate matter were 2 to 3 times higher at the height of a stroller than at the mouth of a standing mannequin during heavy acceleration tests. However, for other operating conditions, the opposite of this result was observed. Additionally, particulate concentrations obtained with the diesel vehicle were typically an order of magnitude or more greater than those obtained with the gasoline vehicle. Particulate matter concentrations during drive-by incidents can easily reach or exceed the low concentrations that can cause acute health effects for brief periods of time. For the case of a 2006 diesel fueled Dodge Ram 2500 and a 2001 gasoline fueled Dodge Ram 1500, the mass of particulate matter inhaled during drive-by incidents was small compared to the mass inhaled daily at ambient conditions. On a per breath basis, however, the mass of particulate matter inhaled was large compared to the mass inhaled at ambient conditions. Finally, it was determined that exposure is directly dependent on the location of a pedestrian with respect to the tailpipe of a passing vehicle

Interdisciplinary research on the nature and properties of ceramic materials

Several investigations concerning the properties and processing of brittle ceramic materials as related to design considerations are briefly described. Surface characterization techniques, fractography, high purity materials, creep properties, impact and thermal shock resistance, and reaction bonding are discussed

Strategy, Core Competence and HR Involvement as Determinants of HR Effectiveness and Refinery Performance

This study examined the impact strategy, core competence, and involvement of HR executives in strategic decision making on the refinery managers\u27 evaluation of the effectiveness of HR and refinery performance among 86 U.S. petro-chemical refineries. Survey results indicated that higher involvement of HR in organizational strategy was strongly related to perceptions of HR effectiveness, and that the relationship was strongest to the extent that refineries pursued a product innovation strategy and viewed skilled employees as their core competence. HR involvement was unrelated to refinery performance, but was actually negatively related to the extent that refineries emphasized efficient production as their core competence

Report on active and planned spacecraft and experiments

Information is presented, concerning active and planned spacecraft and experiments known to the National Space Science Data Center. The information included a wide range of disciplines: astronomy, earth sciences, meteorology, planetary sciences, aeronomy, particles and fields, solar physics, life sciences, and material sciences. These spacecraft projects represented the efforts and funding of individual countries as well as cooperative arrangements among different countries