Corrosion resistance of anodic layers grown on 304L stainless steel at different anodizing times and stirring speeds

Different chemical and physical treatments have been used to improve the properties and functionalities of steels. Anodizing is one of the most promising treatments, due to its versatility and easy industrial implementation. It allows the growth of nanoestructured oxide films with interesting properties able to be employed in different industrial sectors. The present work studies the influence of the anodizing time (15, 30, 45 and 60 min), as well as the stirring speed (0, 200, 400, and 600 rpm), on the morphology and the corrosion resistance of the anodic layers grown in 304L stainless steel. The anodic layers were characterized morphologically, compositionally, and electrochemically, in order to determine the influence of the anodization parameters on their corrosion behavior in a 0.6 mol L-1 NaCl solution. The results show that at 45 and 60 min anodizing times, the formation of two microstructures is favored, associated with the collapse of the nanoporous structures at the metal-oxide interphace. However, both the stirring speed and the anodizing time have a negligeable effect on the corrosion behavior of the anodized 304L SS samples, since their electrochemical values are similar to those of the non-anodized ones

Highly reflective engobes for ink-jet printed coloured porcelain stoneware tiles (CO-2:L05)

Ink-jet decoration is a technology suitable for designing ceramic tiles with solar reflectance (SR) properties. SR is the ratio between the solar energy reflected by a surface and the total incident energy. If incorporated into the cities' building envelope, solar reflective tiles mitigate the Urban Heat Island (UHI) phenomenon, which makes urban centres hotter than rural areas. Even if many efforts have been conducted to develop solar reflective surfaces, little research has been conducted for the development of coloured tiles suitable to be fabricated by ink-jet technology, where the inks tend to counteract the effect of the reflective engobes. To overcome such an issue, the fabrication of solar reflective ink-jet decorated tiles using a reflective engobe was investigated. The engobe was prepared using an industrial CZAS (CaO–ZrO2–Al2O3–SiO2) frit and a ZrSiO4 pigment. The engobe prepared with such frit presented a high SR value (0.918 ± 0.002) and was able to develop ink-jet printed coloured tiles (cool colors) using both white and red porcelain stoneware supports. Overall, it was found that using high engobe thicknesses, white porcelain stoneware supports, and light colour inks allows the fabrication of cool color ink-jet printed tiles. Most of those tiles present solar reflective properties higher than those reported in previous works, even for dark inks that usually tend to counteract the effect of solar reflective engobes

Solar reflective ink-jet printed porcelain stoneware tiles as an alternative for Urban Heat Island mitigation

Digital ink-jet printing is a decoration system for ceramic tiles that requires the application of engobes with high whiteness and opacity, characteristics that can be used to design solar reflective ink-jet decorated tiles. These materials can help to mitigate Urban Heat Island (UHI) phenomenon. Here, the fabrication of ink-jet printed solar reflective tiles using an engobe with high solar reflectance was investigated. Two printing modalities (binary (BIN) and grayscale (GS)), five printing intensities, and four colours were tested. It was found that some of the prepared tiles can be used for mitigating the UHI phenomenon. The solar reflective properties were mainly derived from the reflective engobe, and in some grade, from the mineral composition of the inks. The colour and roughness measurements revealed that the GS modality could prepare ink-jet decorated tiles with good solar reflective properties with a smaller quantity of inks and good soiling resistance

First insights into photocatalytic degradation of HDPE and LDPE microplastics by a mesoporous N-TiO2 coating: Effect of size and shape of microplastics

Microplastics (MPs), which are small plastic debris of ≤5 mm size, are polluting the oceans with negative consequences for their biota. In this work, visible-light photocatalysis of high-density polyethylene (HDPE) and low-density polyethylene (LDPE) MPs in aqueous medium using a mesoporous N-TiO2 coating is proposed as an alternative for fighting MP pollution. Spherical primary HDPE MPs were extracted from commercially available facial scrubs, while film-shaped secondary LDPE MPs were obtained from a plastic bag. For each plastic, two different sizes were tested. Degradation was measured by mass-loss and carbonyl-index (CI) calculation. The results obtained reveal that the photocatalytic degradation of HDPE and LDPE MPs using an N-TiO2 coating was affected by the size and shape of the MPs. Smaller MPs led to higher degradation, while film-shaped MPs led to lower degradation that was related to a poorly illuminated and oxygenated reaction medium. These results set the basis for further investigation on the on the design of more effective photocatalytic-reaction systems for decreasing MP inputs to the environment

The role of the reactive species involved in the photocatalytic degradation of hdpe microplastics using c,n-tio2 powders

Microplastics (MPs) are distributed in a wide range of aquatic and terrestrial ecosystems throughout the planet. They are known to adsorb hazardous substances and can transfer them across the trophic web. To eliminate MPs pollution in an environmentally friendly process, we propose using a photocatalytic process that can easily be implemented in wastewater treatment plants (WWTPs). As photocatalysis involves the formation of reactive species such as holes (h+), electrons (e−), hydroxyl (OH•), and superoxide ion (O2•−) radicals, it is imperative to determine the role of those species in the degradation process to design an effective photocatalytic system. However, for MPs, this information is limited in the literature. Therefore, we present such reactive species’ role in the degradation of high-density polyethylene (HDPE) MPs using C,N-TiO2. Tert-butanol, isopropyl alcohol (IPA), Tiron, and Cu(NO3)2 were confirmed as adequate OH•, h+, O2•− and e− scavengers. These results revealed for the first time that the formation of free OH• through the pathways involving the photogenerated e− plays an essential role in the MPs’ degradation. Furthermore, the degradation behaviors observed when h+ and O2•− were removed from the reaction system suggest that these species can also perform the initiating step of degradation

Circulating proteins to predict COVID-19 severity.

Predicting COVID-19 severity is difficult, and the biological pathways involved are not fully understood. To approach this problem, we measured 4701 circulating human protein abundances in two independent cohorts totaling 986 individuals. We then trained prediction models including protein abundances and clinical risk factors to predict COVID-19 severity in 417 subjects and tested these models in a separate cohort of 569 individuals. For severe COVID-19, a baseline model including age and sex provided an area under the receiver operator curve (AUC) of 65% in the test cohort. Selecting 92 proteins from the 4701 unique protein abundances improved the AUC to 88% in the training cohort, which remained relatively stable in the testing cohort at 86%, suggesting good generalizability. Proteins selected from different COVID-19 severity were enriched for cytokine and cytokine receptors, but more than half of the enriched pathways were not immune-related. Taken together, these findings suggest that circulating proteins measured at early stages of disease progression are reasonably accurate predictors of COVID-19 severity. Further research is needed to understand how to incorporate protein measurement into clinical care