Carbon-Enhanced Cement Clinker

A clinker for use in cement manufacturing includes a cement clinker mixture having crystals of an element that is less electronegative than carbon and carbon bonded to at least a portion of the crystals

Photocatalytic Concrete Pavements: Laboratory Investigation of NO Oxidation Rate Under Varied Environmental Conditions

Concrete pavements containing TiO2 can be used for air pollution control by oxidizing NOX under UV-bearing sunlight. This study employed a bench-scale photoreactor to estimate NO oxidation rates for varied environmental conditions. Rates correlated positively with NO inlet concentration and irradiance and negatively with relative humidity. No correlation occurred with flow rate. A decrease in slab moisture (previously unstudied) positively correlated with NO oxidation rate at 0–2% loss of saturated mass, but negatively correlated at losses greater that 2%. Although prior researchers deemed temperature insignificant, data indicated a positive correlation. Overall, rates ranged from 9.8–64 nmol∙m-2∙s-1

Approximation Assessment of Photocatalytic Air Cleaning Pavements

This paper examines an approximation method to qualitatively assess the air-cleaning performance (i.e., specifically the elimination of aerial nitrogen oxide, NO, released within vehicular exhaust) by full-scale pavements which contain photo-catalytically reactive titanium dioxide under optimal conditions. Two hypothetical road configurations were considered using this method, including both a two-lane, low traffic density (i.e., 4,000 full-day AADT) and a four-lane, moderate traffic density (i.e., 10,000 full-day AADT) design. These options were then comparatively examined on the basis of expected European Union or United States vehicular emission levels. In each case, this method’s day-time-only percentile elimination approximation results were derived using an extrapolation of lab-based specific contaminant elimination rates (i.e., mass NO removed per surface area per time) relative to contaminant release rates which were projected for EU or US vehicular contaminant emission levels. Using this paper’s approximation method, and assuming best-case scenario conditions (i.e., original, un-aged, peak catalytic performance under optimal temperature, relative humidity, etc. conditions), day-timeonly percentile removals in the ~mid-60% to ~90% range were predicted for EU two- and fourlane roadways with low to moderate traffic densities. These EU contaminant elimination approximation percentiles were higher than the actual, observed range (e.g., typically ~mid-10% to ~mid-60% day-time removal percentiles) of published contaminant elimination values which had been measured according to gas-phase contaminant changes during a number of full-scale studies completed at various EU locations and with EU-related vehicle types and emissions. In the case of similar US highway options, this method’s approximated day-time-only elimination percentile results were lower than what was predicted for similar EU road options, with a range of ~30% to ~40%. These latter, lower US road approximations were believed to be related to higher expected US versus EU vehicle emission levels (i.e., by a factor of ~two- to ~three-fold for light and heavy duty vehicles)

First experimental demonstration of temporal hypertelescope operation with a laboratory prototype

In this paper, we report the first experimental demonstration of a Temporal HyperTelescope (THT). Our breadboard including 8 telescopes is firstly tested in a manual cophasing configuration on a 1D object. The Point Spread Function (PSF) is measured and exhibits a dynamics in the range of 300. A quantitative analysis of the potential biases demonstrates that this limitation is related to the residual phase fluctuation on each interferometric arm. Secondly, an unbalanced binary star is imaged demonstrating the imaging capability of THT. In addition, 2D PSF is recorded even if the telescope array is not optimized for this purpose.Comment: Accepted for publication in MNRAS. 11 pages, 25 figure

Efectos de la salinidad sobre la gravedad específica y la viabilidad de huevos de una carpa norteamericana (Ciprinidae)

The influence of salinity on survival, specific gravity, and size of eggs of the endangered Hybognathus amarus (Rio Grande silvery minnow) was studied to provide insight into factors affecting their potential dispersal and fate. Under low salinity conditions egg specific gravity declined significantly in the first hour after spawning as the perivitelline space of the egg filled with water. Egg specific gravity achieved a minimum value approximately 1 h post-spawning and remained approximately constant until hatching, which occurred near 48 h post-spawning at 20°C. Specific gravity of the egg depended on the salinity of the water surrounding the egg: hardened eggs changed rapidly in diameter and specific gravity when exposed to water of higher salinity. Size and specific gravity of H. amarus eggs also differed when the eggs were incubated in different groundwater sources. Experiments indicated that calcium chloride saline solution had a greater effect on egg specific gravity and size than did solutions of sodium or potassium chlorides. Survival of H. amarus eggs declined sharply at salinity greater than 3 (practical salinity units, PSU) and was only 5% at a salinity of 8. Habitat restoration to benefit H. amarus should consider the salinity of habitats in which eggs incubate.El efecto de la salinidad sobre la supervivencia, gravedad específica y talla de los huevos del ciprínido puesto en peligro de extinción, Hybognathus amarus, fue estudiado para proporcionar información sobre los factores que afectan la dispersión y el destino de los huevos. Bajo condiciones de salinidad baja la gravedad específica del huevo disminuyó de forma significativa durante la primera hora después de la puesta, a medida que el espacio del perivitelino del huevo se fue llenando de agua. la gravedad específica del huevo alcanzó un valor mínimo 1 hora después de la puesta y quedó aproximadamente constante hasta eclosión, que ocurrió alrededor de 48 horas tras la puesta a 20˚C. la gravedad específica del huevo dependió de la salinidad del agua que le rodeaba. los huevos con corion endurecido cambiaron rápidamente en diámetro y gravedad específica cuando fueron expuestos a agua de salinidad más alta. El tamaño y la gravedad específica de los huevos de H. amarus también se diferenciaron cuando los huevos fueron incubados en diferentes fuentes de agua subterránea. Los experimentos indicaron que la solución salina del cloruro de calcio tuvo un mayor efecto sobre la gravedad específica del huevo que las soluciones de los cloruros del sodio o del potasio. Expuestos a soluciones de salinidad de más de 3 (PsU), la supervivencia de los huevos de H. amarus disminuyó claramente, bajando a sólo el 5% en la solución de 8. la restauración del hábitat con el objetivo de beneficiar a H. amarus debe considerar la salinidad de los hábitats en los cuales el huevo incuba

Origins of the seasonal variability of PM2.5 sources in a rural site in northern France

Air quality in rural areas results from the crossing of aged air masses transported from urban areas with local emissions dominated by agriculture and vegetation. The result is a complex mixture of primary and secondary atmospheric species, coming from varied sources and geographical areas. We implemented a methodology for deconvoluting and determining the geographical origins of the main aerosol sources impacting a typical rural area of northern France. A one-year field campaign was conducted in a rural site located between Paris and Brussels from 03/2018 to 02/2019. Hourly-based observations of inorganic and organic precursor gases and PM2.5 speciation were collected using on-line instrumentation. The annual PM2.5 concentrations of 12.2 ± 9.23 μg m-3 were explained by four sources extracted through positive matrix factorization analyses: combustion (40.2%), NO3-rich (26.8%), SO4-rich (18%) and mixed aged marine (15%). The combustion and SIA-rich sources drive 85 % of the yearly PM2.5 mass and variability. The combustion factor was most prominent during winter (53.3% of PM2.5 mass) due to high contributions from local and regional transport of biomass burning pollutants (winter OC/EC = 6.0; OC-to-OM factor = 2.05). In summer, it was most likely driven by secondary organic aerosol production and agricultural waste burning events (summer OC/EC = 8.6; OC-to-OM factor= 1.85). Comparing with other regional sites, we observed a strong regional background of carbonaceous particles regardless of the site typology. The SIA fraction is dominated by the NO3-rich source compared to the SO4-rich source. In spring, NO3-rich particles dominate PM2.5 (36.9%) due to intense agricultural activity. The temporal variability is driven by transport processes from the Benelux area in a North-to-South gradient of decreasing concentrations. A minor proportion of the NH4NO3 observed seems to be due to the local effects of morning dew and photochemical oxidation of NO2 in the afternoon. HNO3 appears to be the limiting factor for local NH4NO3 formation. PM2.5 toxicity in rural areas with low population densities should be not only addressed based on mass concentration, but also considering the chemical composition of particles as people from rural environments are exposed to high contributions from biomass burning sources and secondary inorganic aerosols triggered by the NH3 excess

Impacts of Mid-Level Biofuel Content In Gasoline on SIDI Engine-Out and Tailpipe Particulate Matter Emissions

In this work, the influences of ethanol and iso-butanol blended with gasoline on engine-out and post three-way catalyst (TWC) particle size distribution and number concentration were studied using a General Motors (GM) 2.0L turbocharged spark ignition direct injection (SIDI) engine. The engine was operated using the production engine control unit (ECU) with a dynamometer controlling the engine speed and the accelerator pedal position controlling the engine load. A TSI Fast Mobility Particle Sizer (FMPS) spectrometer was used to measure the particle size distribution in the range from 5.6 to 560 nm with a sampling rate of 1 Hz. U.S. federal certification gasoline (E0), two ethanol-blended fuels (E10 and E20), and 11.7% iso-butanol blended fuel (BU12) were tested. Measurements were conducted at 10 selected steady-state engine operation conditions. Bi-modal particle size distributions were observed for all operating conditions with peak values at particle sizes of 10 nm and 70 nm. Idle and low-speed / low-load conditions emitted higher total particle numbers than other operating conditions. At idle, the engine-out particulate matter (PM) emissions were dominated by nucleation mode particles, and the production TWC reduced these nucleation mode particles by more than 50%, while leaving the accumulation mode particle distribution unchanged. At an engine load higher than 6 bar net mean effective pressure (NMEP), accumulation mode particles dominated the engine-out particle emissions, and the TWC had little effect. Compared to the baseline gasoline (E0), E10 does not significantly change PM emissions, while E20 and BU12 both reduce PM emissions under the conditions studied. Iso-butanol was observed to impact PM emissions more than ethanol, with up to 50% reductions at some conditions. In this paper, issues related to PM measurement using the FMPS are also discussed. While some uncertainties are due to engine variation, the FMPS must be carefully maintained in order to achieve repeatable measurement results