Fluid dynamic analysis of dual fluidized bed gasifier for solar applications

A hydrodynamic model of a dual fluidized bed gasifier (DFBG) is developed and its predictions are compared with measurements of solids flux and pressure profiles from a cold flow model (CFM). Then, the performance of a DFBG gasifier is theoretically analyzed in terms of solids circulation and solids distribution under changes in riser and loop seal aeration, solids inventory and particle size, and a sensitivity analysis is made to delimit the model prediction capability. Furthermore, the model is applied to analyze the effects of key design aspects of DFBG, such as the relative size of riser and gasifier, the connection between both units, the circulation rate of solids and their distribution around the system. The model is further used to extend the DFBG operation with external solar energy carried by heated solid particles, i.e. to design solar DFBG (SDFBG). The analysis is focused on the performance with high solids inventory in the gasifier to increase the char conversion (operation with a large solar share) and the control of solids circulation to meet the heat demand of the gasifier with the availability of solar energy. The operation with large solids inventory in the gasifier requires the size of the gasifier to increase considerably compared to that of the conventional DFBG. The substitution of the connection pipe between the riser and the bubbling bed (current design in commercial DFBG) by a lower loop seal enables better control of the solids circulation, thus, benefiting the solar design

Plant height and hydraulic vulnerability to drought and cold

Understanding how plants survive drought and cold is increasingly important as plants worldwide experience dieback with drought in moist places and grow taller with warming in cold ones. Crucial in plant climate adaptation are the diameters of water-transporting conduits. Sampling 537 species across climate zones dominated by angiosperms, we find that plant size is unambiguously the main driver of conduit diameter variation. And because taller plants have wider conduits, and wider conduits within species are more vulnerable to conduction-blocking embolisms, taller conspecifics should be more vulnerable than shorter ones, a prediction we confirm with a plantation experiment. As a result, maximum plant size should be short under drought and cold, which cause embolism, or increase if these pressures relax. That conduit diameter and embolism vulnerability are inseparably related to plant size helps explain why factors that interact with conduit diameter, such as drought or warming, are altering plant heights worldwide

Preservation of underground microbial diversity in ancient subsurface deposits (>6 ma) of the rio tinto basement

The drilling of the Rio Tinto basement has provided evidence of an underground microbial community primarily sustained by the Fe and S metabolism through the biooxidation of pyrite orebodies. Although the gossan is the microbial activity product, which dates back to the Oligocene (25 Ma), no molecular evidence of such activity in the past has been reported yet. A Time of Flight Secondary Ion Mass Spectrometry (ToF-SIMS) molecular analysis of a subsurface sample in the Pe\uf1a de Hierro basement has provided novel data of the ancient underground microbial community. It shows that the microbial remains are preserved in a mineral matrix composed of laminated Fe-oxysulfates and K-and Na-bearing sulfates alternating with secondary silica. In such a mineral substrate, the biomolecule traces are found in five different microstructure associations, (1) <15 micron-sized nodular microstructures composed of POn(2≤n≤4)−, (2) <30 micron-size mi-cronodules containing fatty acids, acylglycerides, and alkanol chains, (3) <20 micro-sized nodules containing NOn −(2≤n≤3) ions, (4) 40-micron size nodules with NH4+ and traces of peptides, and (5) >200-micron thick layer with N-bearing adducts, and sphingolipid and/or peptide traces. It suggests the mineralization of at least five microbial preserved entities with different metabolic ca-pabilities, including: (1) Acidiphilium/Tessaracoccus-like phosphate mineralizers, (2) microbial patches preserving phosphate-free acylglycerides bacteria, (3) nitrogen oxidizing bacteria (e.g., Acidovorax sp.), (4) traces of heterotrophic ammonifying bacteria, and (5) sphingolipid bearing bacteria (e.g., Sphin-gomonadales, and δ-Proteobacteria) and/or mineralized biofilms. The primary biooxidation process acted as a preservation mechanism to release the inorganic ions that ultimately mineralized the microbial structures

Monitoring of the polarized H2O maser emission around the massive protostars W75N(B)-VLA 1 and W75N(B)-VLA 2

Context. Several radio sources have been detected in the high-mass star-forming region W75N(B), with the massive young stellar objects VLA 1 and VLA 2 shown to be of particular interest among them. These objects are thought to be at different evolutionary stages: VLA 1 is in the early stage of photoionization and driving a thermal radio jet, while VLA 2 is a thermal, collimated ionized wind surrounded by a dusty disk or envelope. In both sources, 22 GHz H2O masers have been detected in the past. Those around VLA 1 show a persistent linear distribution along the thermal radio jet, while those around VLA 2 have traced the evolution from a non-collimated to a collimated outflow over a period of ~20 yr. The magnetic field inferred from the H2O masers has shown an orientation rotation following the direction of the major-axis of the shell around VLA 2, whereas it is immutable around VLA 1. Aims. By monitoring the polarized emission of the 22 GHz H2O masers around both VLA 1 and VLA 2 over a period of six years, we aim to determine whether the H2O maser distributions show any variation over time and whether the magnetic field behaves accordingly. Methods. The European VLBI Network was used in full polarization and phase-reference mode in order to determine the absolute positions of the 22 GHz H2O masers with a beam size of ~1 mas and to determine the orientation and the strength of the magnetic field. We observed four epochs separated by two years from 2014 to 2020. Results. We detected polarized emission from the H2O masers around both VLA 1 and VLA 2 in all the epochs. By comparing the H2O masers detected in the four epochs, we find that the masers around VLA 1 are tracing a nondissociative shock originating from the expansion of the thermal radio jet, while the masers around VLA 2 are tracing an asymmetric expansion of the gas that is halted in the northeast where the gas likely encounters a very dense medium. We also found that the magnetic field inferred from the H2O masers in each epoch can be considered as a portion of a quasi-static magnetic field estimated in that location rather than in that time. This allowed us to study the morphology of the magnetic field around both VLA 1 and VLA 2 locally across a larger area by considering the vectors estimated in all the epochs as a whole. We find that the magnetic field in VLA 1 is located along the jet axis, bending toward the north and south at the northeasterly and southwesterly ends of the jet, respectively, reconnecting with the large-scale magnetic field. The magnetic field in VLA 2 is perpendicular to the expansion directions until it encounters the denser matter in the northeast, where the magnetic field is parallel to the expansion direction and agrees with the large-scale magnetic field. We also measured the magnetic field strength along the line of sight in three of the four epochs, with resulting values of -764mG<B||VLA1 < -676 mG and -355mG<B||VLA2<-2426 mG

The Auriga Project: the properties and formation mechanisms of disc galaxies across cosmic time

We introduce a suite of 30 cosmological magneto-hydrodynamical zoom simulations of the formation of galaxies in isolated Milky Way mass dark haloes. These were carried out with the moving mesh code arepo, together with a comprehensive model for galaxy formation physics, including active galactic nuclei (AGN) feedback and magnetic fields, which produces realistic galaxy populations in large cosmological simulations. We demonstrate that our simulations reproduce a wide range of present-day observables, in particular, two-component disc-dominated galaxies with appropriate stellar masses, sizes, rotation curves, star formation rates and metallicities. We investigate the driving mechanisms that set present-day disc sizes/scalelengths, and find that they are related to the angular momentum of halo material. We show that the largest discs are produced by quiescent mergers that inspiral into the galaxy and deposit high-angular momentum material into the pre-existing disc, simultaneously increasing the spin of dark matter and gas in the halo. More violent mergers and strong AGN feedback play roles in limiting disc size by destroying pre-existing discs and by suppressing gas accretion on to the outer disc, respectively. The most important factor that leads to compact discs, however, is simply a low angular momentum for the halo. In these cases, AGN feedback plays an important role in limiting central star formation and the formation of a massive bulge

In pursuit of giants: I. The evolution of the dust-to-stellar mass ratio in distant dusty galaxies

The dust-to-stellar mass ratio (Mdust/M?) is a crucial, albeit poorly constrained, parameter for improving our understanding of the complex physical processes involved in the production of dust, metals, and stars in galaxy evolution. In this work, we explore trends of Mdust/M? with dierent physical parameters and using observations of 300 massive dusty star-forming galaxies detected with ALMA up to z 5. Additionally, we interpret our findings with dierent models of dusty galaxy formation. We find that Mdust/M? evolves with redshift, stellar mass, specific star formation rates, and integrated dust size, but that evolution is dierent for mainsequence galaxies than it is for starburst galaxies. In both galaxy populations, Mdust/M? increases until z 2, followed by a roughly flat trend towards higher redshifts, suggesting ecient dust growth in the distant universe. We confirm that the inverse relation between Mdust/M? and M? holds up to z 5 and can be interpreted as an evolutionary transition from early to late starburst phases. We demonstrate that the Mdust/M? in starbursts reflects the increase in molecular gas fraction with redshift and attains the highest values for sources with the most compact dusty star formation. State-of-the-art cosmological simulations that include self-consistent dust growth have the capacity to broadly reproduce the evolution of Mdust/M? in main-sequence galaxies, but underestimating it in starbursts. The latter is found to be linked to lower gas-phase metallicities and longer dust-growth timescales relative to observations. The results of phenomenological models based on the main-sequence and starburst dichotomy as well as analytical models that include recipes for rapid metal enrichment are consistent with our observations. Therefore, our results strongly suggest that high Mdust/M? is due to rapid dust grain growth in the metal-enriched interstellar medium. This work highlights the multi-fold benefits of using Mdust/M? as a diagnostic tool for: (1) disentangling main-sequence and starburst galaxies up to z 5; (2) probing the evolutionary phase of massive objects; and (3) refining the treatment of the dust life cycle in simulations

Age at menopause and lung function: a Mendelian randomisation study

In observational studies, early menopause is associated with lower forced vital capacity (FVC) and a higher risk of spirometric restriction, but not airflow obstruction. It is, however, unclear if this association is causal. We therefore used a Mendelian randomisation (MR) approach, which is not affected by classical confounding, to assess the effect of age at natural menopause on lung function.We included 94\u200a742 naturally post-menopausal women from the UK Biobank and performed MR analyses on the effect of age at menopause on forced expiratory volume in 1\u2005s (FEV1), FVC, FEV1/FVC, spirometric restriction (FV

Assessment of genetically modified maize\ua04114 for food and feed uses, under Regulation (EC) No\ua01829/2003 (application EFSA-GMO-NL-2014-123)

Maize\ua04114 was developed through Agrobacterium\ua0tumefaciens-mediated transformation to provide protection against certain lepidopteran and coleopteran pests by expression of the Cry1F, Cry34Ab1 and Cry35Ab1 proteins derived from Bacillus\ua0thuringiensis, and tolerance to the herbicidal active ingredient glufosinate-ammonium by expression of the PAT protein derived from Streptomyces viridochromogenes. The molecular characterisation data did not identify issues requiring assessment for food/feed safety. None of the compositional, agronomic and phenotypic differences identified between maize\ua04114 and the non-genetically modified (GM) comparator(s) required further assessment. There were no concerns regarding the potential toxicity and allergenicity of the newly expressed proteins Cry1F, Cry34Ab1, Cry35Ab1 and PAT, and no evidence that the genetic modification might significantly change the overall allergenicity of maize 4114. The nutritional value of food/feed derived from maize 4114 is not expected to differ from that derived from non-GM maize varieties and no post-market monitoring of food/feed is considered necessary. In the case of accidental release of viable maize\ua04114 grains into the environment, maize\ua04114 would not raise environmental safety concerns. The post-market environmental monitoring plan and reporting intervals are in line with the intended uses of maize\ua04114. The genetically modified organism (GMO) Panel\ua0concludes that maize\ua04114 is as safe as the non-GM comparator(s) and non-GM reference varieties with respect to potential effects on human and animal health and the environment in the context of the scope of this application

Geographical variation in therapy for bloodstream infections due to multidrug-resistant enterobacteriaceae: a post hoc analysis of the INCREMENT study

We aimed to describe regional differences in therapy for bloodstream infection (BSI) caused by extended-spectrum ?-lactamase-producing Enterobacteriaceae (ESBL-E) or carbapenemase-producing Enterobacteriaceae (CPE). 1,482 patients in 12 countries were included from an observational study of BSI caused by ESBL-E or CPE. Multivariate logistic regression was used to calculate adjusted odds ratios (aORs) for the influence of country of recruitment on empirical use of ?-lactam/?-lactamase inhibitors (BLBLI) or carbapenems, targeted use of BLBLI for ESBL-E and use of targeted combination therapy for CPE. The use of BLBLI for empirical therapy was least likely in sites from Israel (aOR 0.34, 95% CI 0.14-0.81), Greece (aOR 0.49, 95% CI 0.26-0.94) and Canada (aOR 0.31, 95% CI 0.11-0.88) but more likely in Italy (aOR 1.58, 95% CI 1.11-2.2) and Turkey (aOR 2.09, 95% CI 1.14-3.81), compared to Spain as a reference. Empirical carbapenems were more likely to be used in sites from Taiwan (aOR 1.73, 95% CI 1.03-2.92) and USA (aOR 1.89; 95% CI 1.05-3.39), and less likely in Italy (aOR 0.44, 95% CI 0.28-0.69) and Canada (aOR 0.10, 95% CI 0.01-0.74). Targeted BLBLI for ESBL-E was more likely in sites from Italy. Treatment at sites within Israel, Taiwan, Turkey and Brazil was associated with less combination therapy for CPE. Although this study does not provide precise data on the relative prevalence of ESBL-E or CPE, significant variation in therapy exists across countries even after adjustment for patient factors. A better understanding of what influences therapeutic choices for these infections will aid antimicrobial stewardship efforts.PH is supported by an Australian Postgraduate Award from the University of Queensland. The study was funded by the Ministerio de Economía y Competitividad, Instituto de Salud Carlos III - co-financed by European Development Regional Fund "A way to achieve Europe" ERDF, Spanish Network for the Research in Infectious Diseases (REIPI RD12/0015). BGG, JRB, APH and YC also received funds from the COMBACTE-CARE project (grant agreement 115620), Innovative Medicines Initiative (IMI), the European Union's Seventh Framework Programme (FP7/2007-2013) and in-kind contributions from EFPIA companies

The Next Generation of Axion Helioscopes: The International Axion Observatory (IAXO)

The International Axion Observatory (IAXO) is a proposed 4th-generation axion helioscope with the primary physics research goal to search for solar axions via their Primakoff conversion into photons of 1 \u2013 10 keV energies in a strong magnetic field. IAXO will achieve a sensitivity to the axion-photon coupling ga\u3b3 down to a few 710 1212 GeV 121 for a wide range of axion masses up to 3c 0.25 eV. This is an improvement over the currently best (3rd generation) axion helioscope, the CERN Axion Solar Telescope (CAST), of about 5 orders of magnitude in signal strength, corresponding to a factor 3c 20 in the axion photon coupling. IAXO's sensitivity relies on the construction of a large superconducting 8-coil toroidal magnet of 20 m length optimized for axion research. Each of the eight 60 cm diameter magnet bores is equipped with x-ray optics focusing the signal photons into 3c 0.2 cm2 spots that are imaged by very low background x-ray detectors. The magnet will be built into a structure with elevation and azimuth drives that will allow solar tracking for 12 hours each day. This contribution is a summary of our papers [1], [2] and [3] and we refer to these for further details