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Characterization of HCl Primary Reference Gas Standards for Emission Monitoring
No full textHydrogen chloride (HCl) is a key acidic pollutant emitted by waste-to-energy plants, as well as in industrial processes such as cement manufacturing and fossil fuel combustion. Due to its harmful impact on human health and the environment, strict emission limits are enforced under regulations like the European Industrial Emissions Directive (2010/75/EU), revised in 2024, which require regular monitoring of HCl. In Europe, HCl emissions are typically monitored using wet-chemical methods in accordance with EN 1911. These methods exhibit high uncertainty at concentrations below 10 mg m-³, the EU’s daily average emission limit, prompting the exploration of more accurate alternatives. Optical gas analysers, already approved by the U.S. Environmental Protection Agency, offer a promising alternative with lower measurement uncertainty. These instruments require calibration with reference gas standards of established metrological traceability. To meet this requirement, VSL employed an optical gas analyser to investigate key factors influencing the development of primary reference materials (PRMs) with HCl. The study focused on stability, adsorption behaviour, and pressure dependence of HCl PRMs. As a result, VSL successfully produced PRMs for HCl in high-pressure cylinders, achieving amount fractions as low as 5 µmol mol-1 in nitrogen (approximately 10 mg m-³) with an expanded relative uncertainty of 3% (k = 2). These PRMs are essential for ensuring accurate and reliable calibration of optical gas analysers used in emission monitoring applications
Interlaboratory Comparison to determine the majority composition of Biomethane
No full textWith the energy transition, many studies have been carried out on biogas, as it is considered a renewable energy source. For its use as fuel, a purification process is necessary, becoming biomethane, with a higher concentration of methane and calorific value. The quality control of biomethane from landfills intended different uses is established by ANP Resolution No. 886 of 2022. To comply with this Resolution, it is necessary to correctly measure the composition of the components using high-precision analytical methods. Therefore, the analytical methods were adapted so that they can determine the composition of the major components present in biomethane. A collaborative interlaboratory comparison study was conducted in order to improve and compare measurements composition results for mixtures of biomethane with major components (methane around 90%mol/mol and carbon dioxide around 1.75%mol/mol) with the purpose to assess technical competence of the participants. The study aimed to provide evidence for validated methods using alternative analytical techniques for the proposed measurement using traceable standards, and verify whether the results are in accordance with the parameters reported in the resolution. Through the results, it was possible to conclude that the methods are suitable for their intended use for methane, but for carbon dioxide, there were divergences from the reference value when it was used the portable sensor analysers
The invariance of group occupation across the cosmic web
No full textContext. Recent efforts to identify secondary variations in the halo occupation distribution (HOD) have primarily focused on simulations that examine the role of large-scale cosmic environments, such as superclusters, filaments, and under-dense regions or voids. If present, these variations can yield valuable insights into galaxy formation mechanisms, halo assembly processes, and the influence of external factors on the evolution of cosmic structure.
Aims. We aim to explore whether the secondary trends in the HOD driven by the large-scale structure of the Universe are present observationally. In particular, we examined whether the HOD depends on the distance to key features of the cosmic web by explicitly quantifying these spatial relationships. We further analyzed whether HODs vary across different cosmic environments, as defined by critical point classifications, and assessed the influence of intrinsic galaxy properties, such as the central galaxy color.
Methods. We created volume-limited galaxy samples from SDSS DR18 and used a group catalog to determine halo masses and to identify central and satellite galaxy membership. Additionally, we employed a DisPerSE catalog to locate critical points such as maxima, minima, and filaments in the cosmic web. We assessed how the HOD varies based on proximity to these features and analyzed these variations across five distinct cosmic environments. Furthermore, we investigated trends related to the color of central galaxies and tested the reliability of our results by using alternative DisPerSE catalogs generated with different smoothing scales and persistence thresholds.
Results. Our analysis confirms that the large-scale cosmic environment only weakly influences the HOD. However, second-order environmental dependences might be revealed through a multivariate approach that combines both local and large-scale environment metrics with intrinsic galaxy properties. Future investigations that employ next-generation surveys with improved statistical power, coupled with sophisticated modeling techniques, may provide the necessary precision to detect and characterize these subtle environmental correlations
Black hole merger rates for LISA and LGWA from semi-analytical modelling of light seeds
No full textContext. With the upcoming space- and Moon-based gravitational-wave detectors, LISA and LGWA, a new era of gravitational-wave (GW) astronomy begins, with the possibility of detecting mergers of intermediate-mass black holes (IMBHs) and supermassive black holes (SMBHs).
Aims. We generated populations of synthetic black hole (BH) binaries with masses ranging from the intermediate (103 − 105 M⊙) to the supermassive regime (> 105 M⊙), formed through the dynamical processes of merging haloes and their host galaxies, assuming that each galaxy is initially seeded with a single black hole at its centre. We aimed to estimate the rate of these BH mergers that could be detected by LISA and LGWA.
Methods. Using the PINOCCHI
Diverse reddening distributions in sight lines for type Ia supernovae
No full textContext. Accurate cosmological constraints from type Ia supernovae (SNe) require sufficiently accurate corrections for host-galaxy extinction. Modelling these corrections is challenged by the problem of disentangling the SN’s intrinsic colours from host-galaxy interstellar reddening. The latter is commonly modelled in a probabilistic way assuming an exponential distribution exp(−E(B − V)/τ) as a universal prior, applied across all types of SN host galaxies.
Aims. We tested the robustness of the exponential model of host-galaxy reddening and its universality against predictions based on simulating dust and type Ia SN distributions in host galaxies of different morphological types.
Methods. Our simulations incorporated up-to-date observational constraints on dust masses across host-galaxy morphological types, scaling relations between the dust and stellar disc parameters, and the SN distribution.
Results. We find substantial differences between predicted interstellar reddening in late- (LT) and early-type (ET) host galaxies, primarily driven by the stellar-to-dust mass ratios. The mean simulated reddening in LT galaxies matches those derived from type Ia SN observations well, but it is significantly lower for ET host galaxies. The obtained reddening distributions exhibit an excess of sight lines with zero reddening with respect to the commonly used exponential model, although the difference is quite mild for LT galaxies. On the other hand, the distribution could peak at E(B − V) > 0 when considering a population of young type Ia SNe originating from lower heights within the dust disc of spiral galaxies.
Conclusions. The reddening distribution strongly depends on the SN host-galaxy morphological type. Assuming a universal reddening prior distribution for modelling the peak magnitude-colour relation, which is currently a common practice, gives rise to a spurious scatter in the derived extinction properties. It could also bias relative distances between SNe originating from different host-galaxy populations. The discrepancy between the simulated reddening in average ET host galaxies and the observed occurrence of reddened SNe in these galaxies suggests that reddening does not originate from the interstellar dust expected in these hosts
Zooming in on cluster radio relics
No full textIt is generally accepted that radio relics are the result of synchrotron emission from shock-accelerated electrons. However, current models are still unable to explain several aspects of their formation. In this paper, we focus on three outstanding problems: (i) Mach number estimates derived from radio data do not agree with those derived from X-ray data, (ii) cooling length arguments imply a magnetic field that is at least an order of magnitude larger than the surrounding intracluster medium (ICM), and (iii) spectral index variations do not agree with standard cooling models. We used a hybrid approach to solve these problems; we first identified typical shock conditions in cosmological simulations and then used these to inform idealised shock-tube simulations, which can be run with a substantially higher resolution. We post-processed our simulations with the cosmic ray electron spectra code CRES
Sub-gigayear variability around the star formation main sequence and its contribution to the scatter
No full textAims. We aim to measure the evolution of individual galaxies around the star formation main sequence (SFMS) during the last gigayear as a function of their stellar mass to quantify how much of its scatter is due to short-term variability.
Methods. We derived star formation histories using full spectral fitting for a sample of 8960 galaxies from the MaNGA survey to track the position of the galaxies in the SFMS over the past gigayear.
Results. The variability correlates with both the stellar mass of the galaxies and their current position in both the SFMS and the mass-metallicity relation (MZR), with the position in the latter strongly affecting variability in the star formation rate. While most of the fluctuations are compatible with stochasticity, there is a very weak but statistically significant preference for ∼135 − 150 Myr timescales.
Conclusions. These results indicate that the star formation rate is strongly self-regulated within galaxies, establishing characteristic intensities and timescales for bursts of star formation and quenching episodes. We also find that short-term variability cannot account for the entirety of the scatter in the SFMS. It appears to originate to a similar degree in short-term variability and long-term (halo-level) differentiation and fits predictions from models
Retraction Notice: A Narrative Approach to Detect the Vehicles using color, texture and edge based techniques
No full textWe take a zero tolerance to any situation where fraudulent research is published in our journals. As a result, this article has been retracted by the Publisher because it is suspected to be a nonsensical computer-generated publication with a number of tortured phrases and irrelevant references.
Additional measures have been implemented to prevent these issues from reoccurring.
EDP Sciences is extremely grateful to anonymous whistleblowers and the Problematic Paper Screene
Distalisation de l’arcade mandibulaire grâce aux minivis avec potence dans les trigones rétro-molaires : mise en oeuvre et applications cliniques
No full textIntroduction : après expérimentation depuis 2007, nous validons et consolidons notre protocole de distalisation de l’arcade mandibulaire avec prise d’ancrage sur minivis enfouies dans les trigones rétro-molaires. L’objectif de cet article est tout d’abord de présenter la pose de minivis dans le trigone rétro-molaire associée à l’extraction de la troisième molaire puis d’illustrer les indications de la distalisation de l’arcade mandibulaire par trois situations cliniques. Matériel et méthodes : le protocole est basé sur la pose de minivis enfouies, de 6 mm de longueur, avec potence. Seront ensuite développées les étapes de distalisation de l’arcade mandibulaire permettant la décompensation pré-chirurgicale de classes II squelettiques ou la correction orthodontique d’une classe III dentaire. Résultats : nous obtenons une classe I dentaire et un repositionnement incisif adéquat dans chacun des cas présentés. Conclusion : les minivis, innovation phare des trente dernières années, nous permettent, grâce à la collaboration entre orthodontiste et chirurgien oral, de tendre vers une occlusion idéale
