36 research outputs found

    Modified scattering for the cubic Schr{\"o}dinger equation on product spaces: the nonresonant case

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    We consider the cubic nonlinear Schr{\"o}dinger equation on the spatial domain R×Td\mathbb{R}\times \mathbb{T}^d, and we perturb it with a convolution potential. Using recent techniques of Hani-Pausader-Tzvetkov-Visciglia, we prove a modified scattering result and construct modified wave operators, under generic assumptions on the potential. In particular, this enables us to prove that the Sobolev norms of small solutions of this nonresonant cubic NLS are asymptotically constant

    Exhaust emissions of regulated and unregulated pollutants of passenger cars

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    Exhaust emissions of VOC speciation, aldehydes and other carbonyl compounds, polyaromatics and regulated pollutants are measured using a vehicle bench on a sample of passenger cars. 30 diesel and gasoline cars are tested, complying with ECE 1504 to Euro 3 emission standards, according to 10 real-world driving cycles based on European driving behaviour, with some of them adapted to vehicle size. The emission results of this large-scale measurement campaign show the influence of vehicle technology and driving behaviour on the emission of 100 individual pollutants. In addition, the results are discussed per VOC group and compared with other studies. The influence of the successive emission standards on the emission factors is very positive in most of cases. However, whereas hot CO2 is almost stable, diesel hot NOx, diesel hot and cold VOC, and the 6 most carcinogenic gasoline PAH have increased with standards. Diesel vehicles are less pollutant for CO, HC, CO2, VOC, but more pollutant for NOx and PAH. The distribution of VOC species per molecular family highlights the fact that monoaromatics make up the biggest share (~88 and 62 % resp. for gasoline and diesel vehicles). The second family is the alkanes which contribute resp. 8 and 9% of the total mass of measured VOC. The majority of volatile PAH is observed in the gaseous phase, but the least volatile and the carcinogenic PAH are adsorbed more in particulate phase

    Emission factor modelling and database for light vehicles - Artemis deliverable 3

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    In the frame of the Artemis project, the emission models for atmospheric pollutants have been updated and strongly improved for the road light vehicles. This development is based on a wide and specific measurement campaign, with more than 150 vehicles and about 3500 tests for a large number of pollutants, regulated and non regulated ones. The results of these measurements carried out by several European laboratories are included in a database especially designed, the Artemis LVEM database, available and open to future European measurements data. The Artemis model for light vehicles contains a set of complementary sub-models. The base model calculates the hot emissions for each vehicle category according to the driving behaviour. It contains 5 alternative models: The main model considers traffic situations (discrete model), with emission factors for each of them; A simplified model, built on the same data, takes into account the driving behaviour through the average speed (continuous model); A continuous model, socalled kinematic, considers a limited number of aggregated kinematic parameters; 2 instantaneous models consider some instantaneous parameters as instantaneous speed. These models need input kinematic data of variable complexity and are therefore adapted to different usages, for assessing national emissions, as far as for calculating the impact of a local traffic control. They are associated to models taking into account the influence of several parameters, as cold start, using of auxiliaries like air conditioning, vehicle mileage, ambient air temperature and humidity, road slope and vehicle load, as far as evaporation. The building methods of all these models and the data or models they are based on are presented, as far as the models themselves

    Emission factor modelling for light vehicles within the European Artemis model

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    International audienceThe emission models for atmospheric pollutants have been updated and strongly improved for the road light vehicles. This development is based on a wide and specific measurement campaign, with more than 150 vehicles and about 3500 tests for a large number of pollutants. The results of these measurements are included in a database especially designed, available and open to future European measurements data. The Artemis model for light vehicles contains a set of complementary sub-models. The base model calculates the hot emissions for each vehicle category according to the driving behaviour. It contains 5 alternative models: The main model considers traffic situations (discrete model), with emission factors for each of them; A simplified model, built on the same data, takes into account the driving behaviour through the average speed (continuous model); A continuous model, so-called kinematic, considers a limited number of aggregated kinematic parameters; 2 instantaneous models consider some instantaneous parameters as instantaneous speed. These models are associated to models taking into account the influence of several parameters, as cold start, using of auxiliaries like air conditioning, vehicle mileage, ambient air temperature and humidity, road slope and vehicle load

    Emission factor modelling and database for light vehicles - Artemis deliverable 3

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    In the frame of the Artemis project, the emission models for atmospheric pollutants have been updated and strongly improved for the road light vehicles. This development is based on a wide and specific measurement campaign, with more than 150 vehicles and about 3500 tests for a large number of pollutants, regulated and non regulated ones. The results of these measurements carried out by several European laboratories are included in a database especially designed, the Artemis LVEM database, available and open to future European measurements data. The Artemis model for light vehicles contains a set of complementary sub-models. The base model calculates the hot emissions for each vehicle category according to the driving behaviour. It contains 5 alternative models: The main model considers traffic situations (discrete model), with emission factors for each of them; A simplified model, built on the same data, takes into account the driving behaviour through the average speed (continuous model); A continuous model, socalled kinematic, considers a limited number of aggregated kinematic parameters; 2 instantaneous models consider some instantaneous parameters as instantaneous speed. These models need input kinematic data of variable complexity and are therefore adapted to different usages, for assessing national emissions, as far as for calculating the impact of a local traffic control. They are associated to models taking into account the influence of several parameters, as cold start, using of auxiliaries like air conditioning, vehicle mileage, ambient air temperature and humidity, road slope and vehicle load, as far as evaporation. The building methods of all these models and the data or models they are based on are presented, as far as the models themselves

    Emission factor modelling for light vehicles within the European Artemis model

    Get PDF
    International audienceThe emission models for atmospheric pollutants have been updated and strongly improved for the road light vehicles. This development is based on a wide and specific measurement campaign, with more than 150 vehicles and about 3500 tests for a large number of pollutants. The results of these measurements are included in a database especially designed, available and open to future European measurements data. The Artemis model for light vehicles contains a set of complementary sub-models. The base model calculates the hot emissions for each vehicle category according to the driving behaviour. It contains 5 alternative models: The main model considers traffic situations (discrete model), with emission factors for each of them; A simplified model, built on the same data, takes into account the driving behaviour through the average speed (continuous model); A continuous model, so-called kinematic, considers a limited number of aggregated kinematic parameters; 2 instantaneous models consider some instantaneous parameters as instantaneous speed. These models are associated to models taking into account the influence of several parameters, as cold start, using of auxiliaries like air conditioning, vehicle mileage, ambient air temperature and humidity, road slope and vehicle load

    Unveiling the nature of INTEGRAL objects through optical spectroscopy. IV. A study of six new hard X-ray sources

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    We present further results from our ongoing optical spectrophotometric campaign at the Astronomical Observatory of Bologna in Loiano (Italy) on unidentified hard X-ray sources detected by INTEGRAL. We observed spectroscopically the putative optical counterparts of the INTEGRAL sources IGR J00234+6141, IGR J01583+6713, IGR J06074+2205, IGR J13091+1137 and IGR J20286+2544. We find that the first two are Galactic objects, namely a Cataclysmic Variable at a distance of about 300 pc and a Be/X transient High-Mass X-ray Binary (HMXB) located at about 6.4 kpc, respectively, whereas the last one is identified with MCG +04-48-002, a Starburst/HII galaxy at redshift z = 0.013 hiding a Seyfert 2 nucleus. We identify IGR J13091+1137 as the (likely Seyfert 2 type) active nucleus of galaxy NGC 4992, which we classify as an X-ray Bright, Optically Normal Galaxy; this is the first example of this type of object to be detected by INTEGRAL, and one of the closest of this class. We moreover confirm the possible Be/X nature of IGR J06074+2205, and we estimate it to be at a distance of about 1 kpc. We also reexamine the spectrum of the z = 0.087 elliptical radio galaxy PKS 0352-686, the possible counterpart of the INTEGRAL source IGR J03532-6829, and we find that it is a BL Lac. Physical parameters for these sources are also evaluated by discussing our findings in the context of the available multiwavelength information. These identifications further stress the importance of INTEGRAL in the study of the hard X-ray spectrum of Active Galactic Nuclei, HMXBs and Cataclysmic Variables.Comment: 11 pages, 3 figures, 2 tables, accepted for publication on A&A, main journal. The quality of Fig. 1 was degraded to fit the arXiv uploads size limits. Revised version matches the A&A corrected proof

    Evolution of Surface Hydrology in the Sahelo-Sudanian Strip: An Updated Review

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    In the West African Sahel, two paradoxical hydrological behaviors have occurred during the last five decades. The first paradox was observed during the 1968–1990s ‘Great Drought’ period, during which runoff significantly increased. The second paradox appeared during the subsequent period of rainfall recovery (i.e., since the 1990s), during which the runoff coefficient continued to increase despite the general re-greening of the Sahel. This paper reviews and synthesizes the literature on the drivers of these paradoxical behaviors, focusing on recent works in the West African Sahelo/Sudanian strip, and upscaling the hydrological processes through an analysis of recent data from two representative areas of this region. This paper helps better determine the respective roles played by Land Use/Land Cover Changes (LULCC), the evolution of rainfall intensity and the occurrence of extreme rainfall events in these hydrological paradoxes. Both the literature review and recent data converge in indicating that the first Sahelian hydrological paradox was mostly driven by LULCC, while the second paradox has been caused by both LULCC and climate evolution, mainly the recent increase in rainfall intensity

    Radio Sources in Low-Luminosity Active Galactic Nuclei. III. "AGNs" in a Distance-Limited Sample of "LLAGNs"

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    (abbreviated): This paper presents the results of a high resolution radio imaging survey of all known (96) low-luminosity active galactic nuclei (LLAGNs) at D<19Mpc. We find that almost half of all LINERs and low-luminosity Seyferts have flat-spectrum radio cores when observed at 150mas resolution. Higher (2mas) resolution observations of a flux-limited subsample have provided a 100% (16 of 16) detection rate of pc-scale radio cores, with implied brightness temperatures > 10^8 K. The five LLAGNs with the highest core radio fluxes also have pc-scale `jets.' Compact radio cores are almost exclusively found in massive ellipticals and in type1 nuclei. The core radio power is correlated with the nuclear optical `broad' Halpha luminosity, the nuclear optical `narrow' emission line luminosity and width, and with the galaxy luminosity. In these correlations LLAGNs fall close to the low-luminosity extrapolations of more powerful AGNs. About half of all LLAGNs with multiple epoch data show significant inter-year radio variability. Investigation of a sample of ~150 nearby bright galaxies, most of them LLAGNs, shows that the nuclear (<150mas size) radio power is strongly correlated with both the black hole mass and the galaxy bulge luminosity; linear regression fits to all ~150 galaxies give: log P(2cm) = 1.31 log M_blackhole + 8.77 and log P(2cm) = 1.89 log L_B(bulge) - 0.17. Low accretion rates are implied in both advection- and jet-type models. In brief, all evidence points towards the presence of accreting massive black holes in a large fraction, perhaps all, of LLAGNs.Comment: to appear in A&
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