Context.
Sulfur is a volatile chemical element that plays an important role in tracing the chemical evolution of the Milky Way and external galaxies. However, its nucleosynthesis origin and abundance ...variations in the Galaxy are still unclear because the number of available stellar sulfur abundance measurements is currently rather small.
Aims.
The goal of the present article is to accurately and precisely study the sulfur content of large number of stars located in the solar neighbourhood.
Methods.
We use the parametrisation of thousands of high-resolution stellar spectra provided by the AMBRE Project, and combine it with the automated abundance determination GAUGUIN to derive local thermodynamic equilibrium sulfur abundances for 1855 slow-rotating FGK-type stars. This is the largest and most precise catalogue of sulfur abundances published to date. It covers a metallicity domain as high as ∼2.5 dex starting at M/H ∼ −2.0 dex.
Results.
We find that the sulfur-to-iron abundances ratio is compatible with a plateau-like distribution in the metal-poor regime, and then starts to decrease continuously at M/H ∼ −1.0 dex. This decrease continues towards negative values for supersolar metallicity stars as recently reported for magnesium and as predicted by Galactic chemical evolution models. Moreover, sulfur-rich stars having metallicities in the range − 1.0, −0.5 have very different kinematical and orbital properties with respect to more metal-rich and sulfur-poor ones. Two disc components, associated with the thin and thick discs, are thus seen independently in kinematics and sulfur abundances. The sulfur radial gradients in the Galactic discs have also been estimated. Finally, the enrichment in sulfur with respect to iron is nicely correlated with stellar ages: older metal-poor stars have higher S/M ratios than younger metal-rich ones.
Conclusions.
This work has confirmed that sulfur is an
α
-element that could be considered to explore the Galactic populations properties. For the first time, a chemo-dynamical study from the sulfur abundance point of view, as a stand-alone chemical element, is performed.
A coupled coagulation–Fenton process was applied for the treatment of cosmetic industry effluents. In a first step, FeSO
4 was used as coagulant and the non-precipitated Fe
2+ remaining in ...dissolution was used as catalyst in the further Fenton process. In the coagulation process a huge decrease in total organic carbon (TOC) was achieved, but the high concentration of phenol derivatives was not diminished. The decrease in TOC in the coagulation step significantly reduces the amount of H
2O
2 required in the Fenton process for phenol depletion. The coupled process, using a H
2O
2 dose of only 2
g
l
−1, reduced TOC and total phenol to values lower than 40 and 0.10
mg
l
−1, respectively. The short reaction period (less than 15
min) in TOC and phenol degradation bodes well for improving treatment in a continuous regime. The combination of both processes significantly reduced the ecotoxicity of raw effluent and markedly increased its biodegradability, thus allowing easier treatment by the conventional biological units in conventional sewage treatment plants (STPs).
The outcome of male–male contest competition is known to affect male mating success and is believed to confer fitness benefits to females through preference for dominant males. However, by mating ...with contest winners, females can incur significant costs spanning from decreased fecundity to negative effects on offspring. Hence, identifying costs and benefits of male dominance on female fitness is crucial to unravel the potential for a conflict of interests between the sexes. Here, we investigated males' pre‐ and post‐copulatory reproductive investment and its effect on female fitness after a single contest a using the field cricket Gryllus bimaculatus. We allowed males to fight and immediately measured their mating behaviour, sperm quality and offspring viability. We found that males experiencing a fight, independently of the outcome, delayed matings, but their courtship effort was not affected. However, winners produced sperm of lower quality (viability) compared to losers and to males that did not experience fighting. Results suggest a trade‐off in resource allocation between pre‐ and post‐mating episodes of sexual selection. Despite lower ejaculate quality, we found no fitness costs (fecundity and viability of offspring) for females mated to winners. Overall, our findings highlight the importance of considering fighting ability when assessing male reproductive success, as winners may be impaired in their competitiveness at a post‐mating level.
•Catalytic ozonation of organic acids using CuO/SBA-15 as catalyst was studied.•The effect of inorganic anions on the ozonation process was determined.•The non-catalytic process was severely ...affected. Catalytic ozonation was almost unaffected.•Under non-catalytic ozonation in STP effluent, oxalic acid was depleted by precipitation.•Under catalytic ozonation in STP effluent, oxalate was depleted by ozone oxidation.
The depletion of mesoxalic and oxalic acids, two of the main by-products of wastewater ozone treatment, was studied in non-catalytic and catalytic ozonation using copper oxide supported on mesoporous silica SBA-15 as catalyst. The influence of the main inorganic anions present in natural and STP effluents (bicarbonates, sulphates, chlorides and phosphates) was also studied. The non-catalytic reaction rate was strongly dependent on the presence of inorganic anions and it was also almost inhibited by the presence of particulate material. Catalysed ozonation not only accelerates organic acid depletion, but was almost unaffected by the presence of these inorganic anions, or by the presence of suspended solids. The efficiency of catalytic and non-catalytic ozonation for depletion of both acids was studied in a real STP effluent. The depletion of mesoxalic acid was considerably slowed down in non-catalysed reactions, whereas under catalysed conditions it was not affected. Oxalate depletion was dominated by the formation with calcium of an insoluble salt, the precipitation equilibrium of which reversed only in the presence of a catalyst.
The influence of the oxide support (i.e., Al2O3, Nb2O5, SiO2, and TiO2,) on the surface properties, reduction and oxidation properties, acid-base properties, and catalytic activity of supported ...indium oxide catalysts has been investigated by temperature-programmed reduction/oxidation, thermogravimetry coupled to differential scanning calorimetry, ammonia and sulfur dioxide adsorption calorimetry, and reduction of NOx by ethene in highly oxygen-rich atmosphere. Two series of In2O3-containing catalysts at low (approximately 3 wt %) and at theoretical geometric monolayer (from 20 to 40 wt %) In2O3 content were prepared and their properties were compared with unsupported In2O3 material. Supports able to disperse the In2O3 aggregates with high In stabilization gave rise to active catalytic systems. Among the studied oxide supports, Al2O3 and, to a lower extent, TiO2 were found to be the best supports for obtaining active de-NOx catalysts.
Context.
In order to constrain the models describing circumstellar environments, it is necessary to solve the radiative transfer equation in the presence of absorption and scattering, coupled with ...the equation for radiative equilibrium. However, solving this problem requires much CPU time, which makes the use of automatic minimisation procedures to characterise these environments challenging.
Aims.
In this context, the use of approximate methods is of primary interest. One promising candidate method is the flux-limited diffusion (FLD), which recasts the radiative transfer problem into a non-linear diffusion equation. One important aspect for the accuracy of the method lies in the implementation of appropriate boundary conditions (BCs). We present new BCs for the FLD approximation in circumstellar environments that we apply here to spherically symmetric envelopes.
Methods.
At the inner boundary, the entering flux (coming from the star and from the envelope itself) may be written in the FLD formalism and provides us with an adequate BC. At the free outer boundary, we used the FLD formalism to constrain the ratio of the mean radiation intensity over the emerging flux. In both cases we derived non-linear mixed BCs relating the surface values of the mean specific intensity and its gradient. We implemented these conditions and compared the results with previous benchmarks and the results of a Monte Carlo radiative transfer code. A comparison with results derived from BCs that were previously proposed in other contexts is presented as well.
Results.
For all the tested cases, the average relative difference with the benchmark results is below 2% for the temperature profile and below 6% for the corresponding spectral energy distribution or the emerging flux. We point out that the FLD method together with the new outer BC also allows us to derive an approximation for the emerging flux. This feature avoids additional formal solutions for the radiative transfer equation in a set of rays (ray-tracing computations).
Conclusions.
The FLD approximation together with the proposed new BCs performs well and captures the main physical properties of the radiative equilibrium in spherical circumstellar envelopes.
Context. In order to constrain the models describing circumstellar environments, it is necessary to solve the radiative transfer equation in the presence of absorption and scattering, coupled with ...the equation for radiative equilibrium. However, solving this problem requires much CPU time, which makes the use of automatic minimisation procedures to characterise these environments challenging. Aims. In this context, the use of approximate methods is of primary interest. One promising candidate method is the flux-limited diffusion (FLD), which recasts the radiative transfer problem into a non-linear diffusion equation. One important aspect for the accuracy of the method lies in the implementation of appropriate boundary conditions (BCs). We present new BCs for the FLD approximation in circumstellar environments that we apply here to spherically symmetric envelopes. Methods. At the inner boundary, the entering flux (coming from the star and from the envelope itself) may be written in the FLD formalism and provides us with an adequate BC. At the free outer boundary, we used the FLD formalism to constrain the ratio of the mean radiation intensity over the emerging flux. In both cases we derived non-linear mixed BCs relating the surface values of the mean specific intensity and its gradient. We implemented these conditions and compared the results with previous benchmarks and the results of a Monte Carlo radiative transfer code. A comparison with results derived from BCs that were previously proposed in other contexts is presented as well. Results. For all the tested cases, the average relative difference with the benchmark results is below 2% for the temperature profile and below 6% for the corresponding spectral energy distribution or the emerging flux. We point out that the FLD method together with the new outer BC also allows us to derive an approximation for the emerging flux. This feature avoids additional formal solutions for the radiative transfer equation in a set of rays (ray-tracing computations). Conclusions. The FLD approximation together with the proposed new BCs performs well and captures the main physical properties of the radiative equilibrium in spherical circumstellar envelopes.
This review aims to assess different technologies for the on-site treatment of hospital wastewater (HWW) to remove pharmaceutical compounds (PhCs) as sustances of emerging concern at a bench, pilot, ...and full scales from 2014 to 2020. Moreover, a rough characterisation of hospital effluents is presented. The main detected PhCs are antibiotics and psychiatric drugs, with concentrations up to 1.1 mg/L. On the one hand, regarding the presented technologies, membrane bioreactors (MBRs) are a good alternative for treating HWW with PhCs removal values higher than 80% in removing analgesics, anti-inflammatories, cardiovascular drugs, and some antibiotics. Moreover, this system has been scaled up to the pilot plant scale. However, some target compounds are still present in the treated effluent, such as psychiatric and contrast media drugs and recalcitrant antibiotics (erythromycin and sulfamethoxazole). On the other hand, ozonation effectively removes antibiotics found in the HWW (>93%), and some studies are carried out at the pilot plant scale. Even though, some families, such as the X-ray contrast media, are recalcitrant to ozone. Other advanced oxidation processes (AOPs), such as Fenton-like or UV treatments, seem very effective for removing pharmaceuticals, Antibiotic Resistance Bacteria (ARBs) and Antibiotic Resistance Genes (ARGs). However, they are not implanted at pilot plant or full scale as they usually consider extra reactants such as ozone, iron, or UV-light, making the scale-up of the processes a challenging task to treat high-loading wastewater. Thus, several examples of biological wastewater treatment methods combined with AOPs have been proposed as the better strategy to treat HWW with high removal of PhCs (generally over 98%) and ARGs/ARBs (below the detection limit) and lower spending on reactants. However, it still requires further development and optimisation of the integrated processes.
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•This review focuses on 2014 to 2020 papers related to hospital effluents treatments.•Membrane bioreactors remove pharmaceuticals (>80%) at pilot plant scale.•Advanced Oxidation processes require further development at high scales.•Combined technologies also remove antibiotic resistance bacteria and genes.•Advanced oxidation processes are promising alternatives to treat hospital effluents.
Alumina-supported indium oxide (In2O3) catalysts with In loadings between 2 and 22 wt% were prepd. by impregnation and characterized for their main properties. Surface properties, such as the surface ...area; surface In content, measured by XPS; and acidity and basicity, measured both by adsorption microcalorimetry using ammonia and sulfur dioxide as probe mols. and by IR spectroscopy of pyridine adsorption, were detd. Bulk properties, namely the crystallog. structure as detd. by powder X-ray diffraction (XRD) anal. and the redox character of the In2O3-dispersed phase as detd. by redox cycles performed both in a flow app. and in a thermobalance coupled with a differential scanning microcalorimeter (TG-DSC), were studied. The results obtained were interpreted in terms of In2O3 surface dispersion or aggregation. The catalysts tested in the redn. of NOx by ethene in an oxygen-rich atm. showed an interesting ability to selectively reduce NOx to N2, independently of the In loading. The weakness of the oxidative properties of the In2O3 phases limited the ethene combustion and made the catalysts able to reduce NOx even at high temp. (up to 550°C). The rates of nitrogen formation depended strongly on the In2O3 aggregation state; the In centers were very active even at low amts.
n-Hexane molecules tend to adopt mostly linear conformations inside the ZSM-11 zeolite channels, with no particular preference for channel intersections. The ratio between the width of the zeolite ...channel and the height of the linear alkane is close to one, by which the channels at full load have very little available volume. As a consequence the effective density of
n-hexane inside the channels is higher than that of the bulk liquid.
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►
n-Hexane molecules pack inside the channels of ZSM-11 zeolites at higher densities than in the bulk fluid and this effect is essentially temperature independent. ► This feature, confirmed by molecular simulation and volumetric and microcalorimetric adsorption experiments, is due to the appropriate matching of the channel diameter and the molecular width in mostly all-trans conformations. ► This seems to be a common feature with other linear alkanes and the related ZSM-5 zeolite.
The effects of packing of
n-hexane molecules in the channels of a ZSM-11 zeolite are studied by means of adsorption microcalorimetric and volumetric experiments and molecular simulation. We find that the packing density within the zeolite channels is significantly higher than the bulk liquid density. This effect, somewhat characteristic of the
n-hexane/ZSM-11 adsorbate/adsorbent system, was first found by Guil et al. (1998)
13 and it is here confirmed by new adsorption measurements carried out at various temperatures and on pure silica ZSM-11, and very especially by means of extensive grand-canonical Monte Carlo simulations. The analysis of simulation snapshots, angular distribution functions and intermolecular correlations, in conjunction with the calorimetric measurements, indicate that the excess of packing is not connected to any form of phase transition, but results from the optimum size matching of the
n-hexane molecules within the zeolite channels. As a result, this feature is mostly temperature independent, being induced by steric effects. Computer simulations performed for
n-butane and
n-octane on ZSM-11 indicate that this effect is to be expected for other linear alkanes as well.
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