High temperature oxidation and burner rig testing of different TBCs in the frame of the European Project TOPPCOAT: A summary of results

The major S&T objective of the project is the development of improved TBC systems using advanced bonding concepts in combination with additional protective functional coatings. The first specific objective will be to use these developments to provide a significant improvement to state-of-the-art APS coatings and hence provide a cost-effective alternative to EB-PVD. The second objective will be to combine these new concepts with new coating technologies to provide new, advance materials for thermal barrier systems with a capability exceeding the performance of EB-PVD coatings

Laser Flash technique: A critical analysis of testing parameters and models for fitting experimental data

Laser Flash is considered the standard technique for measuring the thermal diffusivity of solids. To avoid any permanent damage of the sample when a LF measurement is carried out on brittle materials, characterized by very low values of thermal diffusivity, thermal effusivity, and toughness, as the case of freestanding APS TBC samples, the energy density deposited onto the sample surface should be minimized. The damaging effect of the energy deposited on the surface of free standing TBC samples during LF measurements has been experimentally investigated. The damage has been evaluated experimentally and analyzed by suitable heat conduction modeling and some suggestions are provided [1]. ZrO2 is semitransparent to near IR radiation. This is the typical wavelenght range of the laser heating source of the laser flash equipment. Moreover, the characterization of TBCs at high temperatures is particularly interesting as the typical working temperature of gas-turbine is \u3e1000 °C [2]. At these temperatures the radiative heat transfer through the TBC becomes more and more relevant. The effect of blackening surfaces by a thin layer of graphite is considered [3]. Experiments are carried out at ambient temperature by means of a thermographic camera, at higher temperature in vacuum until 1200 °C and in argon atmosphere until 1000 °C. Data are analysed taking into account the heat exchange with the environment [4]. Successively, the possibility of radiative exchange between the two blackened sides of the sample [5] is taken into account. Finally, the possibility of simultaneous heating of the two sides of the sample, due to the semitransparency of the material is considered. This last model explains the anomalous immediate heating of the side facing the detector as shown in Fig. 1 Laser Flash is a very reliable technique for measuring thermal diffusivity of single layer samples but, especially for coatings, measuring their thermal diffusivity directly on a component they are deposited onto is a need. To satisfy this request in-reflection configuration photothermal techniques have been developed and successfully applied [6] . Furthermore, when the thickness of the substrate is not too thick, also the LF technique can be used on two-layer samples as some algorithms for estimating thermal diffusivity of a single material in a two layer sample have been developed since many years [7,8]. In particular all these models require to know the density, the specific heat and the thermal conductivity of the second layer. The effects of the uncertainty in the evaluation/estimation of the thermophysical parameters of the second layer will be discussed theoretically and compared with some experiments designed to highlight the most critical issues in this type of measurement. Please click Additional Files below to see the full abstract

Thermophysical, microstructural characterization and non-destructive control of TBCs by photothermal and thermographic techniques: some lessons learned

Since several years, photothermal and thermographic techniques have been used to perform the thermo-physical characterisation of TBCs and the non-destructive assessment of TBC integrity. Furthermore, in the last decade some attempts to use these techniques for carrying out a non-destructive microstructural characterization have been done, as well. In this talk the description of a thermographic technique able to simultaneously measure the through-the-thickness and the in-plane thermal diffusivity of free standing TBCs samples and thus giving evidence of the typical microstructural anisotropy of APS TBCs will be provided [1]. Furthermore, some effects of the laser radiation used in a laser flash experiment on the TBC thermal diffusivity and a new model for fitting the experimental data will be presented [2,3]. The main results of an activity focused to identify potentialities and limitations of using Laser flash experiments on multilayered samples for estimating thermal diffusivity of TBCs samples will be provided. A theoretical and experimental analysis of the real capabilities of infrared techniques to estimate the porosity content and the microstructure of porous ceramic materials such as thermal barrier coatings (TBCs) by studying thermal diffusivity variations when pores are filled with air or vacuum will be provided [4,5]. Please click Additional Files below to see the full abstract

Chemostratigraphy of the Mina Verdún Group and other cement-grade Proterozoic limestone deposits in Uruguay

The Mina Verdún Group (MVG) was erected by Poiré et al. (2003) to include a sedimentary succession exposed in the homonymous mine, which is made up (from base to top) of (Fig. 2): -Don Mario Formation: metapelites -La Toma Formation: marls -El Calabozo Formation: grey stromatolitic limestones -Gibraltar Formation: dolomitic marls, red limestones and massive dolostones Thickness of the succession at its stratotype reaches 285 m. An important feature of the thick (up to 170 m) limestones of El Calabozo Formation is the occurrence of a stromatolite assemblage composed almost exclusively by Conophyton (Fig. 2). These limestones are of considerable economic importance, because they constitute the basis of a large cement industry. A minimum age for the succession is provided by the unconformably overlying Las Ventanas Formation, which on the basis of acritarch biostratigraphy is assigned to the lower Ediacaran (635-575 Ma, Blanco & Gaucher, 2005). Gaucher et al. (2004d) assign the succession exposed in the Burgue o limestone Quarry, 40 km to the south of Mina Verdún, to the MVG. The succession exposed in the quarry, 150 m in thickness, includes (from base to top): metamarls, limestones, stromatolitic Conophytonlimestones and massive dolostones. At the stratotype and in Burgueño Quarry, conglomerates overly with erosional unconformity the MVG. These conglomerates, assigned to LVFm (Blanco & Gaucher, 2004, 2005), include a level of diamictites and breccias at the contact to the MVG, which has been recognized as a palaeokarst surface. The assocation of palaeokarst surfaces developed on top of carbonate successions and overlain by glacigenic diamictites is well known for a number of Neoproterozoic successions. Dropstones occur in laminated mudstones, associated with diamictites. However, no carbonates occur on top of the diamictites. We carried out 13C and 18O analyses of carbonates and corresponding petrographic studies at two sections of the MVG and also on carbonates mined for the cement industry at La Plata Mine (ANCAP), with the aim of testing chemostratigraphic tools as an aid for the exporation of cement-grade carbonates. corresponding petrographic studies at two sections of the MVG and also on carbonates mined for the cement industry at La Plata Mine (ANCAP), with the aim of testing chemostratigraphic tools as an aid for the exporation of cement-grade carbonates. and massive dolostones. At the stratotype and in Burgueño Quarry, conglomerates overly with erosional unconformity the MVG. These conglomerates, assigned to LVFm (Blanco & Gaucher, 2004, 2005), include a level of diamictites and breccias at the contact to the MVG, which has been recognized as a palaeokarst surface. The assocation of palaeokarst surfaces developed on top of carbonate successions and overlain by glacigenic diamictites is well known for a number of Neoproterozoic successions. Dropstones occur in laminated mudstones, associated with diamictites. However, no carbonates occur on top of the diamictites. We carried out 13C and 18O analyses of carbonates and corresponding petrographic studies at two sections of the MVG and also on carbonates mined for the cement industry at La Plata Mine (ANCAP), with the aim of testing chemostratigraphic tools as an aid for the exporation of cement-grade carbonates. corresponding petrographic studies at two sections of the MVG and also on carbonates mined for the cement industry at La Plata Mine (ANCAP), with the aim of testing chemostratigraphic tools as an aid for the exporation of cement-grade carbonates. Mina Verdún, to the MVG. The succession exposed in the quarry, 150 m in thickness, includes (from base to top): metamarls, limestones, stromatolitic Conophytonlimestones and massive dolostones. At the stratotype and in Burgueño Quarry, conglomerates overly with erosional unconformity the MVG. These conglomerates, assigned to LVFm (Blanco & Gaucher, 2004, 2005), include a level of diamictites and breccias at the contact to the MVG, which has been recognized as a palaeokarst surface. The assocation of palaeokarst surfaces developed on top of carbonate successions and overlain by glacigenic diamictites is well known for a number of Neoproterozoic successions. Dropstones occur in laminated mudstones, associated with diamictites. However, no carbonates occur on top of the diamictites. We carried out 13C and 18O analyses of carbonates and corresponding petrographic studies at two sections of the MVG and also on carbonates mined for the cement industry at La Plata Mine (ANCAP), with the aim of testing chemostratigraphic tools as an aid for the exporation of cement-grade carbonates. corresponding petrographic studies at two sections of the MVG and also on carbonates mined for the cement industry at La Plata Mine (ANCAP), with the aim of testing chemostratigraphic tools as an aid for the exporation of cement-grade carbonates. and massive dolostones. At the stratotype and in Burgueño Quarry, conglomerates overly with erosional unconformity the MVG. These conglomerates, assigned to LVFm (Blanco & Gaucher, 2004, 2005), include a level of diamictites and breccias at the contact to the MVG, which has been recognized as a palaeokarst surface. The assocation of palaeokarst surfaces developed on top of carbonate successions and overlain by glacigenic diamictites is well known for a number of Neoproterozoic successions. Dropstones occur in laminated mudstones, associated with diamictites. However, no carbonates occur on top of the diamictites. We carried out 13C and 18O analyses of carbonates and corresponding petrographic studies at two sections of the MVG and also on carbonates mined for the cement industry at La Plata Mine (ANCAP), with the aim of testing chemostratigraphic tools as an aid for the exporation of cement-grade carbonates. corresponding petrographic studies at two sections of the MVG and also on carbonates mined for the cement industry at La Plata Mine (ANCAP), with the aim of testing chemostratigraphic tools as an aid for the exporation of cement-grade carbonates. considerable economic importance, because they constitute the basis of a large cement industry. A minimum age for the succession is provided by the unconformably overlying Las Ventanas Formation, which on the basis of acritarch biostratigraphy is assigned to the lower Ediacaran (635-575 Ma, Blanco & Gaucher, 2005). Gaucher et al. (2004d) assign the succession exposed in the Burgue o limestone Quarry, 40 km to the south of Mina Verdún, to the MVG. The succession exposed in the quarry, 150 m in thickness, includes (from base to top): metamarls, limestones, stromatolitic Conophytonlimestones and massive dolostones. At the stratotype and in Burgueño Quarry, conglomerates overly with erosional unconformity the MVG. These conglomerates, assigned to LVFm (Blanco & Gaucher, 2004, 2005), include a level of diamictites and breccias at the contact to the MVG, which has been recognized as a palaeokarst surface. The assocation of palaeokarst surfaces developed on top of carbonate successions and overlain by glacigenic diamictites is well known for a number of Neoproterozoic successions. Dropstones occur in laminated mudstones, associated with diamictites. However, no carbonates occur on top of the diamictites. We carried out 13C and 18O analyses of carbonates and corresponding petrographic studies at two sections of the MVG and also on carbonates mined for the cement industry at La Plata Mine (ANCAP), with the aim of testing chemostratigraphic tools as an aid for the exporation of cement-grade carbonates. corresponding petrographic studies at two sections of the MVG and also on carbonates mined for the cement industry at La Plata Mine (ANCAP), with the aim of testing chemostratigraphic tools as an aid for the exporation of cement-grade carbonates. and massive dolostones. At the stratotype and in Burgueño Quarry, conglomerates overly with erosional unconformity the MVG. These conglomerates, assigned to LVFm (Blanco & Gaucher, 2004, 2005), include a level of diamictites and breccias at the contact to the MVG, which has been recognized as a palaeokarst surface. The assocation of palaeokarst surfaces developed on top of carbonate successions and overlain by glacigenic diamictites is well known for a number of Neoproterozoic successions. Dropstones occur in laminated mudstones, associated with diamictites. However, no carbonates occur on top of the diamictites. We carried out 13C and 18O analyses of carbonates and corresponding petrographic studies at two sections of the MVG and also on carbonates mined for the cement industry at La Plata Mine (ANCAP), with the aim of testing chemostratigraphic tools as an aid for the exporation of cement-grade carbonates. corresponding petrographic studies at two sections of the MVG and also on carbonates mined for the cement industry at La Plata Mine (ANCAP), with the aim of testing chemostratigraphic tools as an aid for the exporation of cement-grade carbonates. Mina Verdún, to the MVG. The succession exposed in the quarry, 150 m in thickness, includes (from base to top): metamarls, limestones, stromatolitic Conophytonlimestones and massive dolostones. At the stratotype and in Burgueño Quarry, conglomerates overly with erosional unconformity the MVG. These conglomerates, assigned to LVFm (Blanco & Gaucher, 2004, 2005), include a level of diamictites and breccias at the contact to the MVG, which has been recognized as a palaeokarst surface. The assocation of palaeokarst surfaces developed on top of carbonate successions and overlain by glacigenic diamictites is well known for a number of Neoproterozoic successions. Dropstones occur in laminated mudstones, associated with diamictites. However, no carbonates occur on top of the diamictites. We carried out 13C and 18O analyses of carbonates and corresponding petrographic studies at two sections of the MVG and also on carbonates mined for the cement industry at La Plata Mine (ANCAP), with the aim of testing chemostratigraphic tools as an aid for the exporation of cement-grade carbonates. corresponding petrographic studies at two sections of the MVG and also on carbonates mined for the cement industry at La Plata Mine (ANCAP), with the aim of testing chemostratigraphic tools as an aid for the exporation of cement-grade carbonates. and massive dolostones. At the stratotype and in Burgueño Quarry, conglomerates overly with erosional unconformity the MVG. These conglomerates, assigned to LVFm (Blanco & Gaucher, 2004, 2005), include a level of diamictites and breccias at the contact to the MVG, which has been recognized as a palaeokarst surface. The assocation of palaeokarst surfaces developed on top of carbonate successions and overlain by glacigenic diamictites is well known for a number of Neoproterozoic successions. Dropstones occur in laminated mudstones, associated with diamictites. However, no carbonates occur on top of the diamictites. We carried out 13C and 18O analyses of carbonates and corresponding petrographic studies at two sections of the MVG and also on carbonates mined for the cement industry at La Plata Mine (ANCAP), with the aim of testing chemostratigraphic tools as an aid for the exporation of cement-grade carbonates. corresponding petrographic studies at two sections of the MVG and also on carbonates mined for the cement industry at La Plata Mine (ANCAP), with the aim of testing chemostratigraphic tools as an aid for the exporation of cement-grade carbonates. Conophyton (Fig. 2). These limestones are of considerable economic importance, because they constitute the basis of a large cement industry. A minimum age for the succession is provided by the unconformably overlying Las Ventanas Formation, which on the basis of acritarch biostratigraphy is assigned to the lower Ediacaran (635-575 Ma, Blanco & Gaucher, 2005). Gaucher et al. (2004d) assign the succession exposed in the Burgue o limestone Quarry, 40 km to the south of Mina Verdún, to the MVG. The succession exposed in the quarry, 150 m in thickness, includes (from base to top): metamarls, limestones, stromatolitic Conophytonlimestones and massive dolostones. At the stratotype and in Burgueño Quarry, conglomerates overly with erosional unconformity the MVG. These conglomerates, assigned to LVFm (Blanco & Gaucher, 2004, 2005), include a level of diamictites and breccias at the contact to the MVG, which has been recognized as a palaeokarst surface. The assocation of palaeokarst surfaces developed on top of carbonate successions and overlain by glacigenic diamictites is well known for a number of Neoproterozoic successions. Dropstones occur in laminated mudstones, associated with diamictites. However, no carbonates occur on top of the diamictites. We carried out 13C and 18O analyses of carbonates and corresponding petrographic studies at two sections of the MVG and also on carbonates mined for the cement industry at La Plata Mine (ANCAP), with the aim of testing chemostratigraphic tools as an aid for the exporation of cement-grade carbonates. corresponding petrographic studies at two sections of the MVG and also on carbonates mined for the cement industry at La Plata Mine (ANCAP), with the aim of testing chemostratigraphic tools as an aid for the exporation of cement-grade carbonates. and massive dolostones. At the stratotype and in Burgueño Quarry, conglomerates overly with erosional unconformity the MVG. These conglomerates, assigned to LVFm (Blanco & Gaucher, 2004, 2005), include a level of diamictites and breccias at the contact to the MVG, which has been recognized as a palaeokarst surface. The assocation of palaeokarst surfaces developed on top of carbonate successions and overlain by glacigenic diamictites is well known for a number of Neoproterozoic successions. Dropstones occur in laminated mudstones, associated with diamictites. However, no carbonates occur on top of the diamictites. We carried out 13C and 18O analyses of carbonates and corresponding petrographic studies at two sections of the MVG and also on carbonates mined for the cement industry at La Plata Mine (ANCAP), with the aim of testing chemostratigraphic tools as an aid for the exporation of cement-grade carbonates. corresponding petrographic studies at two sections of the MVG and also on carbonates mined for the cement industry at La Plata Mine (ANCAP), with the aim of testing chemostratigraphic tools as an aid for the exporation of cement-grade carbonates. Mina Verdún, to the MVG. The succession exposed in the quarry, 150 m in thickness, includes (from base to top): metamarls, limestones, stromatolitic Conophytonlimestones and massive dolostones. At the stratotype and in Burgueño Quarry, conglomerates overly with erosional unconformity the MVG. These conglomerates, assigned to LVFm (Blanco & Gaucher, 2004, 2005), include a level of diamictites and breccias at the contact to the MVG, which has been recognized as a palaeokarst surface. The assocation of palaeokarst surfaces developed on top of carbonate successions and overlain by glacigenic diamictites is well known for a number of Neoproterozoic successions. Dropstones occur in laminated mudstones, associated with diamictites. However, no carbonates occur on top of the diamictites. We carried out 13C and 18O analyses of carbonates and corresponding petrographic studies at two sections of the MVG and also on carbonates mined for the cement industry at La Plata Mine (ANCAP), with the aim of testing chemostratigraphic tools as an aid for the exporation of cement-grade carbonates. corresponding petrographic studies at two sections of the MVG and also on carbonates mined for the cement industry at La Plata Mine (ANCAP), with the aim of testing chemostratigraphic tools as an aid for the exporation of cement-grade carbonates. and massive dolostones. At the stratotype and in Burgueño Quarry, conglomerates overly with erosional unconformity the MVG. These conglomerates, assigned to LVFm (Blanco & Gaucher, 2004, 2005), include a level of diamictites and breccias at the contact to the MVG, which has been recognized as a palaeokarst surface. The assocation of palaeokarst surfaces developed on top of carbonate successions and overlain by glacigenic diamictites is well known for a number of Neoproterozoic successions. Dropstones occur in laminated mudstones, associated with diamictites. However, no carbonates occur on top of the diamictites. We carried out 13C and 18O analyses of carbonates and corresponding petrographic studies at two sections of the MVG and also on carbonates mined for the cement industry at La Plata Mine (ANCAP), with the aim of testing chemostratigraphic tools as an aid for the exporation of cement-grade carbonates. corresponding petrographic studies at two sections of the MVG and also on carbonates mined for the cement industry at La Plata Mine (ANCAP), with the aim of testing chemostratigraphic tools as an aid for the exporation of cement-grade carbonates. o limestone Quarry, 40 km to the south of Mina Verdún, to the MVG. The succession exposed in the quarry, 150 m in thickness, includes (from base to top): metamarls, limestones, stromatolitic Conophytonlimestones and massive dolostones. At the stratotype and in Burgueño Quarry, conglomerates overly with erosional unconformity the MVG. These conglomerates, assigned to LVFm (Blanco & Gaucher, 2004, 2005), include a level of diamictites and breccias at the contact to the MVG, which has been recognized as a palaeokarst surface. The assocation of palaeokarst surfaces developed on top of carbonate successions and overlain by glacigenic diamictites is well known for a number of Neoproterozoic successions. Dropstones occur in laminated mudstones, associated with diamictites. However, no carbonates occur on top of the diamictites. We carried out 13C and 18O analyses of carbonates and corresponding petrographic studies at two sections of the MVG and also on carbonates mined for the cement industry at La Plata Mine (ANCAP), with the aim of testing chemostratigraphic tools as an aid for the exporation of cement-grade carbonates. corresponding petrographic studies at two sections of the MVG and also on carbonates mined for the cement industry at La Plata Mine (ANCAP), with the aim of testing chemostratigraphic tools as an aid for the exporation of cement-grade carbonates. and massive dolostones. At the stratotype and in Burgueño Quarry, conglomerates overly with erosional unconformity the MVG. These conglomerates, assigned to LVFm (Blanco & Gaucher, 2004, 2005), include a level of diamictites and breccias at the contact to the MVG, which has been recognized as a palaeokarst surface. The assocation of palaeokarst surfaces developed on top of carbonate successions and overlain by glacigenic diamictites is well known for a number of Neoproterozoic successions. Dropstones occur in laminated mudstones, associated with diamictites. However, no carbonates occur on top of the diamictites. We carried out 13C and 18O analyses of carbonates and corresponding petrographic studies at two sections of the MVG and also on carbonates mined for the cement industry at La Plata Mine (ANCAP), with the aim of testing chemostratigraphic tools as an aid for the exporation of cement-grade carbonates. corresponding petrographic studies at two sections of the MVG and also on carbonates mined for the cement industry at La Plata Mine (ANCAP), with the aim of testing chemostratigraphic tools as an aid for the exporation of cement-grade carbonates. Conophytonlimestones and massive dolostones. At the stratotype and in Burgueño Quarry, conglomerates overly with erosional unconformity the MVG. These conglomerates, assigned to LVFm (Blanco & Gaucher, 2004, 2005), include a level of diamictites and breccias at the contact to the MVG, which has been recognized as a palaeokarst surface. The assocation of palaeokarst surfaces developed on top of carbonate successions and overlain by glacigenic diamictites is well known for a number of Neoproterozoic successions. Dropstones occur in laminated mudstones, associated with diamictites. However, no carbonates occur on top of the diamictites. We carried out 13C and 18O analyses of carbonates and corresponding petrographic studies at two sections of the MVG and also on carbonates mined for the cement industry at La Plata Mine (ANCAP), with the aim of testing chemostratigraphic tools as an aid for the exporation of cement-grade carbonates. corresponding petrographic studies at two sections of the MVG and also on carbonates mined for the cement industry at La Plata Mine (ANCAP), with the aim of testing chemostratigraphic tools as an aid for the exporation of cement-grade carbonates. 13C and 18O analyses of carbonates and corresponding petrographic studies at two sections of the MVG and also on carbonates mined for the cement industry at La Plata Mine (ANCAP), with the aim of testing chemostratigraphic tools as an aid for the exporation of cement-grade carbonates.Fil: Gaucher, Claudio. Universidad de la República; UruguayFil: Sial, Alcides. Universidade Federal de Pernambuco; BrasilFil: Poire, Daniel Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones Geológicas. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Investigaciones Geológicas; ArgentinaFil: Cernuschi, Federico. Universidad de la República; UruguayFil: Ferreira, Valderez P.. Universidade Federal de Pernambuco; BrasilFil: Ghiglino, Leticia. Universidade Federal de Pernambuco; BrasilFil: Gozález, Pablo. Universidad de la República; UruguayFil: Martinez, Gabriela. Universidad de la República; UruguayFil: Pimmentel, Marcio M.. Universidade do Brasília; Brasil5th South Ameri

Thermal conductivity of binary ceramic composites made of insulating and conducting materials comprising full composition range – applied to yttria partially stabilized zirconia and molybdenum disilicide

The thermal diffusivity and conductivity of dense and porous binary composites having an insulating and conducting phase were studied across its entire composition range. Experimental evaluation has been performed with MoSi2 particles embedded into yttria partially stabilized zirconia (YPSZ) as prepared by spark plasma sintering (SPS). The thermal diffusivity of the composites was measured with Flash Thermography (FT) and Laser Flash Analysis (LFA) techniques. Subsequently, the thermal conductivity was determined with the measured heat capacity and density of the composites. The actual volume fraction of the conducting phase of the composites was determined with image analysis of X-ray maps recorded with scanning electron microscopy (SEM). The phases present and their density were determined with X-ray diffractometry (XRD) using Rietveld refinement. The thermal diffusivity increases with increasing volume fraction of MoSi2. Porosity reduces the thermal diffusivity, but the effect diminishes with high volume fractions MoSi2. The thermal diffusivity as a function of the MoSi2 volume fraction of the YPSZ composites is captured by modelling, which includes the porosity effect and the high conductivity paths due to the percolation of the conductive phase

SARS-CoV-2 vaccines: What we know, what we can do to improve them and what we could learn from other well-known viruses

: In recent weeks, the rate of SARS-CoV-2 infections has been progressively increasing all over the globe, even in countries where vaccination programs have been strongly implemented. In these regions in 2021, a reduction in the number of hospitalizations and deaths compared to 2020 was observed. This decrease is certainly associated with the introduction of vaccination measures. The process of the development of effective vaccines represents an important challenge. Overall, the breakthrough infections occurring in vaccinated subjects are in most cases less severe than those observed in unvaccinated individuals. This review examines the factors affecting the immunogenicity of vaccines against SARS-CoV-2 and the possible role of nutrients in modulating the response of distinct immune cells to the vaccination

Influence of embedded MoSi2 particles on the high temperature thermal conductivity of SPS produced yttria-stabilised zirconia model thermal barrier coatings

To prolong the lifetime of thermal barrier coatings (TBCs) recently a new method of microcrack healing has been developed, which relies on damage initiated thermal decomposition of embedded molybdenum disilicide (MoSi2) particles within the TBC matrix. While these MoSi2 particles have a beneficial effect on the structural stability of the TBC, the high thermal conductivity of MoSi2 may have an unfavourable but as yet unquantified impact on the thermal conductivity of the TBCs. In this work the thermal conductivity of spark plasma sintering (SPS) produced yttria-stabilised zirconia (YSZ) model thermal barrier coatings containing 10 or 20 vol.% of MoSi2 healing particles was investigated using the laser flash method. Measurements were performed on free-standing composite material over a temperature range from room temperature up to 1000 °C. Microstructural analysis was carried out by SEM combined with image analysis to determine the size, distribution and area fraction of healing particles. The measurements were compared with the results from microstructure-based multi-physics finite element (FE) models and analytical models (the asymmetric Bruggeman model and the Nielsen model) in order to study the effects of the addition of MoSi2 particles as well as the presence of micro-pores on the apparent thermal conductivity. The results show a strongly non-linear increase in the thermal conductivity of the composite material with the MoSi2 volume fraction and a dependence on the aspect ratio of MoSi2 particles. Interparticle connectivity is shown to play a big role too

High Risk of Secondary Infections Following Thrombotic Complications in Patients With COVID-19

Background. This study’s primary aim was to evaluate the impact of thrombotic complications on the development of secondary infections. The secondary aim was to compare the etiology of secondary infections in patients with and without thrombotic complications. Methods. This was a cohort study (NCT04318366) of coronavirus disease 2019 (COVID-19) patients hospitalized at IRCCS San Raffaele Hospital between February 25 and June 30, 2020. Incidence rates (IRs) were calculated by univariable Poisson regression as the number of cases per 1000 person-days of follow-up (PDFU) with 95% confidence intervals. The cumulative incidence functions of secondary infections according to thrombotic complications were compared with Gray’s method accounting for competing risk of death. A multivariable Fine-Gray model was applied to assess factors associated with risk of secondary infections. Results. Overall, 109/904 patients had 176 secondary infections (IR, 10.0; 95% CI, 8.8–11.5; per 1000-PDFU). The IRs of secondary infections among patients with or without thrombotic complications were 15.0 (95% CI, 10.7–21.0) and 9.3 (95% CI, 7.9–11.0) per 1000-PDFU, respectively (P = .017). At multivariable analysis, thrombotic complications were associated with the development of secondary infections (subdistribution hazard ratio, 1.788; 95% CI, 1.018–3.140; P = .043). The etiology of secondary infections was similar in patients with and without thrombotic complications. Conclusions. In patients with COVID-19, thrombotic complications were associated with a high risk of secondary infections

Geology of the Cretaceous Lascano-East intrusive complex : magmatic evolution and mineralization potential of the Merin Basin, Uruguay

The Cretaceous Merín aborted-rift basin of eastern Uruguay is composed of sub-alkaline Paraná-Etendeka province basaltic flows and shallow intrusives (~133 to 131 Ma), rhyolitic ignimbrites (~130 to 128 Ma) and associated mildly alkaline to alkaline intrusions and volcanic rocks (~128 to 127 Ma). Four intrusive complexes from 20 to >30 kilometers wide are identified by circular positive gravity and cospatial magnetic anomalies and are aligned in a northeast-southwest trend. Whereas the outcropping Valle Chico complex is mainly composed by mildly alkaline syenites, drilling at Lascano East revealed mostly alkaline gabbros and trachytes. The Lascano-West and San Luis concealed complexes are inferred by the location of the aeromagnetic and gravity anomalies. Ten lithogeochemical units were identified and grouped into three rock associations. A sub-alkaline group composed of Treinta y Tres A basalts, Treinta y Tres B basalts and gabbros, Lavalleja rhyolitic ignimbries and San Miguel granodiorite granophyres; a mildly alkaline group including the Santa Lucía basalts and gabbros, Aiguá rhyolites, Valle Chico syenites and India Muerta rhyolites; and an alkaline group including the Lascano alkaline gabbro to trachyte series and the Arrayán olivine basalts. The only observed sedimentary rocks are conglomerates grouped as the Quebracho Formation. Melting of a shallow mantle source (depleted mantle) combined with abundant crustal assimilation likely produced the diversity of the sub-alkaline magmatic rocks. The mildly alkaline and alkaline rocks were likely produced by mixing of this source with a deeper mantle source (ocean island basalt – like), or by progressively deeper mantle melting and lowering degrees of partial melting. Hydrothermally altered and mineralized rocks were identified in the central zone of the complex where the sub-alkaline and mildly alkaline lavas are intruded by mildly alkaline to alkaline gabbros and trachyte dikes on top of inferred mafic alkaline intrusions. The mineralization and alteration can be divided into two associations. First, potassic hydrothermally altered zones and younger superimposed intermediate argillic alteration in sub-alkaline to mildly alkaline felsic rocks are cut by similarly altered Lascano alkaline series dikes. Pyrite disseminations together with pyrite, quartz-pyrite and fluorite veins in these rocks are associated with weak gold, bismuth, thallium and molybdenum anomalies. Second, local potassic alteration of mildly alkaline basalts cut by the Lascano alkaline dikes, showing sparse millimetric to one centimeter quartz-pyrite and phyllosilicate-pyrite veins associated to weak molybdenum anomalies. Local quartz-chalcopyrite-pyrite veins and copper anomalies were detected in the contact of the basalts with one Santa Lucía mildly alkaline gabbro. No evidence of mineralization is found in the Valle Chico complex, the only outcropping complex of the Merín basin. The only other evidence of mineralization in the basin are fluorite veins enriched in tungsten, boron and yttrium cutting the Precambrian basement near the basin edge. The lack of mineralization in the Valle Chico complex could be explained by differences in the level of erosion throughout the basin due to the interplay of subsidence caused by mafic intrusion and different crustal thicknesses at each side of the Sierra Ballena shear zone. While Valle Chico was more deeply eroded, the possibly mineralized roof wall-rocks were preserved in the concealed complexes to the East. The Merín basin was broadly contemporaneous and close in space to the magmatism in the Luderitz and Damaraland basins in Namibia and more distal complexes in Brazil. These were possibly linked to similar melt sources, evolutionary paths, and emplacement mechanisms, related to the opening of the southern Atlantic Ocean in the Paraná – Etendeka provinces. Based on typical mineralization in complexes from Brazil and Namibia the mineralization potential of the Merín basin may also expand to niobium, zirconium, phosphate, uranium, thorium and rare earths. These ores may be related to possible concealed carbonatites or other alkaline rocks not yet discovered in the Merín basin. However, the conditions for the formation of laterites, which play an important role in the economic deposits of Brazil were probably unlikely.Keywords: Merín basin, southern Atlantic Ocean rifting, Mineralization, Alkaline complex, Cretaceous, Intrusive complex, Lascan

Charging processes of Na4Mn9O18 electrode in aqueous electrolyte

Recent trends in electrochemical energy storage –the renewed interest in aqueous electrolytes, the development of nanostructured and/or hybridized materials, the advent of unconventional systems– call for detailed analyses of charging processes. We address this issue in studying a sodium manganese oxide (Na4Mn9O18, NMO) electrode in aqueous environment. Charge storage is examined by cyclic voltammetry (CV) in a wide range of sweep rate (ν) and by equivalent circuit modelling of the electrode impedance response. Voltammetry shows that, with increasing ν, the insertion process evolves from a quasi-equilibrium behavior (ν ≤ 0.1 mV s–1) towards a diffusion controlled regime overlapping with capacitive charging (ν ≥ 0.2 mV s–1), and culminates at even higher rate (ν > 2 mV s–1) in mixed mass transport ohmic control. Impedance analysis permits to discriminate the varying character of charge storage, revealing the low frequency dominance of faradaic insertion and the rising contribution of pseudocapacitive and double layer charging at higher frequency. We show that the frequency decomposition of charging mechanisms obtained by this analysis can be reconciled with the CV analysis. For further clarification of the above analysis in particular, and as a relevant aspect of the NMO behavior in general, we evaluate the chemical diffusion coefficient of Na-ion as a function of potential