Durability of etics incorporating high reflectance pigments in finishing coatings

The increase of the durability of building materials and components presents great importance since it contributes to a more sustainable environment by increasing its service life. The development of new building materials and technologies with improved thermal characteristics, such as ETICS with high reflectance coatings, contributes to meet the thermal requirements defined by the European regulation. However, the importance of the durability assessment of new solutions cannot be understated as it plays a key role in the prevention of future early degradation. This paper has the objective of assessing the durability of ETICS incorporating high reflectance pigments in organic coatings. The solar reflectance can be increased through optimized material formulations with the inclusion of nanoparticles in coatings. If the near-infrared (NIR) solar absorption is reduced, the referred benefits can be achieved even in darker colours. One of the main concerns is the durability of the entire system, but the stability of the darker colours must also be taken into account. As such, relevant parameters solar absorptance, surface temperature and colour were measured in a long-term in-situ experimental campaign, in ETICS specimens with distinct coatings. The effect of the thermal insulation layer, in the referred parameters, was also evaluated, by measuring the effect of the same coatings in samples with traditional substrates. The solar absorptance was measured with a pyranometer with an adapted methodology based on the ASTM E1918 standard. The surface temperature of the samples was continuously monitored for an extended period enabling a comparison of the benefits under different climatic conditions. The colour was determined by the CIELAB colour space, by measuring the L*A*B parameters. The results showed that the incorporation of high reflectance pigments leads to a decrease in the solar absorptance and surface temperature even in darker colours. The pigments also influenced the lightness of the coating, by increasing the L parameter. The potential benefits of these thermal enhanced systems combine an enhanced thermal performance, durability and a higher diversity of aesthetic features

Constraints on warm dark matter models from high-redshift long gamma-ray bursts

Structures in Warm Dark Matter (WDM) models are exponentially suppressed below a certain scale, characterized by the dark matter particle mass, mx . Since structures form hierarchically, the presence of collapsed objects at high-redshifts can set strong lower limits on mx . We place robust constraints on mx using recent results from the Swift database of high-redshift gamma-ray bursts (GRBs). We parameterize the redshift evolution of the ratio between the cosmic GRB rate and star formation rate (SFR) as 1d (1+z)\u3b1 , thereby allowing astrophysical uncertainties to partially mimic the cosmological suppression of structures in WDM models. Using a maximum likelihood estimator on two different z > 4 GRB subsamples (including two bursts at z > 8), we constrain mx 1.6-1.8 keV at 95% CL, when marginalized over a flat prior in \u3b1. We further estimate that 5 years of a SVOM-like mission would tighten these constraints to mx 2.3 keV. Our results show that GRBs are a powerful probe of high-redshift structures, providing robust and competitive constraints on mx

Colour degradation of facade coatings - the effect of nanopigments incorporation

The increasing interest in the use of a wide range of colours in buildings, especially dark colours, may lead to the early degradation of the facades, compromising their aesthetic and thermal performance. On the other hand, the incorporation of nanopigments with high reflectance properties can contribute to reducing the absorption of solar radiation. The nanoparticles contribute to increasing the solar reflectance of coatings, decreasing the surface temperature and improving the coating performance. This work evaluates the natural degradation of the colour of finishing coat with nanopigments in ETICS. The colour parameters were evaluated in different ETICS specimens, considering the colour black and red with and without incorporated nanopigments, under natural ageing. The colour measurement was performed according to ISO 1164-4, using a portable spectrophotometer. The results confirmed that the use of nanopigments improved the colour durability, promoting the maintenance of the colours parameters. The total colour difference was lower than the perceptible by the human eyes, even as the lower variation on chroma and hue parameters of the colours with nanopigments. In summary, the incorporation of nanoparticles in finishing coat of ETICS can contribute to increasing their durability and improve their thermal performance without compromising the aesthetic characteristics

Impact of Incorporating NIR Reflective Pigments in Finishing Coatings of ETICS

Near-infrared (NIR) reflective materials are being developed for mitigating building cooling needs. Their use contributes to broadening the range of colours, responding to the urban aesthetic demand without compromising the building performance. Despite the increase in NIR reflective pigments investigation, there is still a knowledge gap in their applicability, impact, and durability in multilayer finishing coatings of External Thermal Insulation Composite Systems (ETICS). Hence, the main goal of this work consists of evaluating the impact of incorporating NIR reflective pigments (NRP) in the solar reflectance of the surface layer of ETICS, without affecting the colour perception, as well as their influence on the colour durability and surface temperature. As such, colour, solar reflectance, and surface temperature were monitored for 2 years in dark-coloured specimens of ETICS, with and without NRP and a primer layer. It was confirmed that the main contribution of NRP is the increase of solar reflectance and, consequently, the decrease in surface temperature, especially for high exterior temperatures (around 30 degrees C). Moreover, these pigments highly increase the NIR reflectance without affecting the visible colour. In addition, they contribute to maintaining the colour characteristics. The application of primer increased the surface temperature, especially for higher exterior temperatures. However, it contributes to a lower colour difference and solar reflectance variation, which is an important achievement for durability purposes

Solar reflectance of ETICS finishing coatings - a comparison of experimental techniques

The solar reflectance has a significant role in the thermal behaviour and surface temperature of ETICS finishing coats. Incomplete information of solar reflectance of ETICS with nanopigments can sometimes difficult their adequate selection. In this work, the solar reflectance of different ETICS finishing coats was measured using two distinct methodologies, and the importance of the adopted procedure was discussed. The experimental methodologies used were: i) the adapted conventional pyranometer technique (non-ASTM E 1918A), which measures the global solar reflectance; and ii) the use of the spectrophotometry, to measure the spectral reflectance. It was verified that the El 918A methodology is more sensitive to environmental conditions than the spectrophotometry procedure. Also, the calculation of solar reflectance with spectrophotometer can be carried out by the 50 or 100 ordinates. However, the surface characteristics, as the concentration of pigments and roughness, affect more the solar reflectance measured with the spectrophotometer than with the pyranometer. It was verified that the nanopigments could improve solar reflectance and change the spectral reflectance. The results showed that, if the procedure is well applied, both methodologies could be used to evaluate the advantages of incorporating nanopigments in facade finishing coatings and also to assess the durability of these materials

Estudo do polimorfismo do gene do hormônio de crescimento em rebanhos da raça Nelore do estado da Bahia.

Título em inglês: Study of the polymorphism of the gene of the hormone of growth in a Nelore breed of the state of the Bahia

Is there still room to explore cyclodextrin glycosyltransferase-producers in Brazilian biodiversity?

In the present work, different Brazilian biomes aiming to identify and select cyclodextrin glycosyltransferase-producer bacteria are explored. This enzyme is responsible for converting starch to cyclodextrin, which are interesting molecules to carry other substances of economic interest applied by textile, pharmaceutical, food, and other industries. Based on the enzymatic index, 12 bacteria were selected and evaluated, considering their capacity to produce the enzyme in culture media containing different starch sources. It was observed that the highest yields were presented by the bacteria when grown in cornstarch. These bacteria were also characterized by sequencing of the 16S rRNA region and were classified as Bacillus, Paenibacillus, Gracilibacillus and Solibacillus.publishersversionpublishe

Heart Rate Variability Analysis in Revascularized Individuals Submitted to an Anaerobic Potency Test

The objective of this study was to analyze the behavior of autonomic modulation before, during and after the Modified Wingate Test (WanMT), through the analysis of Heart Rate Variability (HRV). Six volunteers between the ages of 40 and 70, post-revascularization procedures (angioplasty and/or surgery, mean duration 10 months), were submitted to supervised training for at least 10 to 14 months. The following protocol, divided into 5 phases, was used: 1) Rest Phase (RP): 180 seconds; 2) Submaximum Phase (SP): 30 seconds; 3) Maximum Phase (MP): 30 seconds; 4) Active Recuperation Phase (ARP); 120 seconds and; 5) Passive Recuperation Phase (PRP): 180 seconds. For the WanMT Test, we selected the load of 3.75% of corporal weight for all volunteers. To analyze the HRV, we used the following parameters: the interval RRr, MNN, SDNN, RMSSD and PNN50. We only observed results for the group according to RMSSD parameters during the rest phase of the test protocol in which the group remained in vagal presence and during all other phases in vagal depression. However, when we analyzed the PNN50, we observed that the group was in medium vagal presence during all of the phases of the test though there was no statistically significant difference (p> 0.05) between the phases. Therefore, we can say that all of the individuals had a similar profile in the autonomic response to the WanMT, confirmed by the parameters studied in the analysis of the HRV in the time domain

Comparative study of the synthesis and characterization of reduced graphene oxide (RGO) using an eco friendly reducing agent

In this work, the reducing action of four reducing agents—ascorbic acid, inorganic salt, sodium hydrosulfte and polysaccharide—was investigated. Some reducing agents, in addition to being environmentally friendly, are good substitutes for dangerous chemicals used industrially. Graphene oxide (GO) was synthesized by the modifed Hummers method and was reduced with ascorbic acid (RGO-AA), inorganic salt (RGO-SI), sodium hydrosulfte (RGO-HS) and polysaccharide (RGO-PS). The microstructural, morphological, optical, electrochemical and thermal properties of GO, RGO-AA, RGOSI, RGO-HS and RGO-PS were characterized by x-ray difraction (XRD), Raman spectroscopy, Fourier transform infrared spectroscopy/attenuated total refectance (FTIR-ATR), x-ray photoelectron spectroscopy (XPS), high-resolution transmission electron microscopy (HRTEM)/energy-dispersive x-ray spectroscopy (EDS), feld-emission scanning electron microscopy (FEG-SEM), UV–Vis, zeta potential, thermogravimetric analysis (TGA) and diferential scanning calorimetry (DSC). The conclusive results showed that the four agents demonstrated reducing capability. It was observed that the reducing agent derived from inverted sugar (polysaccharide) was the most efcient because it presented a reduction in GO with fewer microstructural defects, a lower number of sheets, and electrochemical and thermal properties superior to the properties obtained from conventional reducing agents. Therefore, with these impressive results obtained with polysaccharide, it was concluded that an efective GO reducing agent was obtained using this green and ecological product, resulting in a reduced graphene oxide (RGO) with few sheets and fewer defects and, consequently, with greater supercapacitor application potential.CNPq -Conselho Nacional de Desenvolvimento Científico e Tecnológico(45034/2020-3