3,261 research outputs found
Heterogeneous Photocatalytic Degradation of Ibuprofen Over TiO2–Ag Supported on Activated Carbon from Waste Tire Rubber
In recent years it has been discovered that some common use medicines, such as ibuprofen and other nonsteroidal anti-inflammatory drugs, are found in water sources in concentrations that have the potential to affect aquatic organisms. On the other hand, waste used tires are a massive problem for the environment due to the leaching of toxic compounds to soils and water. Also, the exposition to environmental conditions can make them sources of vectors like mosquitoes. In this work, three activated carbon (AC) catalysts derived from waste tire rubber, titanium dioxide and silver were synthesized using the sol–gel method. Morphological characterizations such as SEM and TEM were performed in which, the agglomeration of titanium particles and silver crystals on the surface of the AC is evident. In the XRD analysis, the presence of elemental silver nanoparticles was detected. In the diffuse reflectance spectroscopy analysis, the decrease in the titanium band gap, as well as activity in the visible spectrum, was observed. The photocatalytic tests were performed at pH 3 and 7 in the presence of UV/Vis radiation. These tests show that there are differences between the catalyst in both, UV and visible regions. Adsorption is a major phenomenon for the removal of ibuprofen, followed by photolytic decomposition. In visible spectra, the catalysts show a good performance for the removal of ibuprofen
The Entropy of the Rotating Charged Black Threebrane from a Brane-Antibrane System
We show that a model based on a D3-brane--anti-D3-brane system at finite
temperature, proposed previously as a microscopic description of the
non-rotating black threebrane of type IIB supergravity arbitrarily far from
extremality, can also successfully reproduce the entropy of the rotating
threebrane with arbitrary charge (including the neutral case, which corresponds
to the Kerr black hole in seven dimensions). Our results appear to confirm in
particular the need for a peculiar condition on the energy of the two gases
involved in the model, whose physical interpretation remains to be elucidated.Comment: 12 pages, references added in section 1 and
Prevalence of Toxocara eggs in Latin American parks: a systematic review and meta-analysis
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Novel Method for Wind Turbines Blades Damage Classification using Image Processing
Wind turbine generators are spreading around the world due to its advantages over fossil fuels. Structural monitoring of them is important to increase operation and reduce maintenance times. Visual inspection is highly influenced by the human factor due to the working conditions. Image processing supported by vision systems offers high advantages reducing times, being the software and processing algorithms, which generates added value. In this paper, a novel method for wind turbines blades damages analysis is presented using image processing and a classifier based on dimensional features. The image acquisition is performed using a reflex camera with a telephoto and geo-location enabled. The faults analyzed include cracks, edge erosion, and electric discharge
Novel Method for Wind Turbines Blades Damage Classification using Image Processing
75-79Wind turbine generators are spreading around the world due to its advantages over fossil fuels. Structural monitoring of them is important to increase operation and reduce maintenance times. Visual inspection is highly influenced by the human factor due to the working conditions. Image processing supported by vision systems offers high advantages reducing times, being the software and processing algorithms, which generates added value. In this paper, a novel method for wind turbines blades damages analysis is presented using image processing and a classifier based on dimensional features. The image acquisition is performed using a reflex camera with a telephoto and geo-location enabled. The faults analyzed include cracks, edge erosion, and electric discharge
Clinical features, hospitalisation and deaths associated with monkeypox: a systematic review and meta-analysis
Introduction: A multicountry monkeypox disease (MPX) outbreak began in May 2022 in Europe, leading to the assessment as a potential Public Health Emergency of International Concern (PHEIC) on June 23, 2022. Some observational studies have partially characterised clinical features, hospitalisations, and deaths. However, no systematic reviews of this MPX outbreak have been published. Methods: We performed a systematic review with meta-analysis, using five databases to assess clinical features, hospitalisations, complications and deaths of MPX confirmed or probable cases. Observational studies, case reports and case series, were included. We performed a random-effects model meta-analysis to calculate the pooled prevalence and 95% confidence interval (95% CI). In addition, we carried out a subgroup analysis according to the continents and a sensitivity analysis excluding studies classified as having a high risk of bias. Results: A total of 19 articles were included, using only 12 articles in the quantitative synthesis (meta-analysis). For 1958 patients, rash (93%, 95% CI 80–100%), fever (72%, 95% CI 30–99%), pruritus (65%, 95% CI 47–81%), and lymphadenopathy (62%, 47–76%), were the most prevalent manifestations. Among the patients, 35% (95% CI 14–59%) were hospitalised. Some 4% (95% CI 1–9%) of hospitalised patients had fatal outcomes (case fatality rate, CFR). Conclusion: MPX is spreading rapidly, with a third of hospitalised patients, but less than 5% with fatal outcomes. As this zoonotic virus spreads globally, countries must urgently prepare human resources, infrastructure and facilities to treat patients according to the emerging guidelines and the most reliable clinical information.Revisión por pare
Single stage electrochemical exfoliation method for the production of few-layer graphene via intercalation of tetraalkylammonium cations
We present a non-oxidative production route to few layer graphene via the electrochemical intercalation of tetraalkylammonium cations into pristine graphite. Two forms of graphite have been studied as the source material with each yielding a slightly different result. Highly orientated pyrolytic graphite (HOPG) offers greater advantages in terms of the exfoliate size but the source electrode set up introduces difficulties to the procedure and requires the use of sonication. Using a graphite rod electrode, few layer graphene flakes (2 nm thickness) are formed directly although the flake diameters from this source are typically small (ca. 100–200 nm). Significantly, for a solvent based route, the graphite rod does not require ultrasonication or any secondary physical processing of the resulting dispersion. Flakes have been characterized using Raman spectroscopy, atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS)
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Estimating wind speed and capacity factors in Mexico using reanalysis data
In the fundamental stage of resource assessment, high-quality wind speed measurements are required to estimate power production. However, this high-quality data is not always available, and therefore the analysis of alternative sources becomes essential. In this work, we analyze the ability of MERRA-2 to represent wind speed characteristics at 24 anemometric stations in Mexico. The assessment was carried out using the Pearson correlation coefficient between the observed time series, and the obtained by interpolating bias-corrected reanalysis-estimated wind speed to all locations for different time-averaging periods. Results showed that the reanalysis’ performance is not uniform throughout the country; it depends on the time resolution, local orographic conditions, and the relationship between the local flow and the large-scale circulation. Based on these results, the country was subdivided into eight regions. The best-represented region was the Chivela Pass, where the winds are tightly linked to the interaction between the large-scale circulation and the local orography. The worst performing regions were located where the land sea-mask and orography at the reanalysis’ resolution may not be accurate enough to reproduce the station’s wind speeds. Reanalysis-estimated capacity factors exhibit large interannual variability in some stations, which can have significant consequences for the operation of individual wind farms and the power grid. The results show that, while caution should be exercised when applying reanalyses to wind resource assessment in Mexico, reanalysis wind power estimates can be a valuable tool to investigate the feasibility and installed capacity requirements for Mexico to meet its renewable energy targets
Acceptance towards Monkeypox Vaccination: A Systematic Review and Meta-Analysis
Vaccination it is considered a vital strategy in order to mitigate monkeypox by protecting from severe disease and helping in reduction of hospitalisations. In this sense, this study aims to estimate the global prevalence of vaccination acceptance against monkeypox. We conducted a systematic review with a comprehensive search strategy for the following databases: PubMed, Scopus and Web of Science. A random-effect model meta-analysis was carried out using observational studies assessing the intention of vaccines against monkeypox from multiple continents. The quality assessment was developed using the Newcastle-Ottawa Scale adapted for cross-sectional studies. In addition, a subgroup analysis by study location and population and a sensitivity analysis was developed.Eleven cross-sectional studies were included. A total of 8045 participants were included. The pooled prevalence of monkeypox vaccination acceptance in all participants was 56.0% (95%CI: 42.0–70.0%). In the subgroup analysis of monkeypox vaccine acceptance according to continents, the prevalence of vaccine acceptance was 50.0% (95%CI: 24.0–76.0%) in Asian countries and 70.0% (95%CI: 55.0–84.0%) in European countries. The prevalence of vaccine acceptance was 43.0% (95%CI: 35.0–50.0%) in the general population, 63.0% (95%CI: 42.0–70.0%) in healthcare workers, and 84.0% (95%CI: 83.0–86.0%) in the LGBTI community. Despite the high prevalence of monkeypox vaccination acceptance in the LGBTI community found in our study, vaccination acceptance from healthcare workers and the general population are lower. Governments could use these results for planning, developing or promoting vaccination strategies and public health policies focused on these populations.Revisión por pare
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