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Oil pollutant identification based on excitation-emission matrix of UV-induced fluorescence and deep convolutional neural network Texte intégral
2022
Li, Ying | Jia, Yunpeng | Cai, Xiaohua | Xie, Ming | Zhang, Zhenduo
Identifying the types of oil pollutants in a spill event can help determine the source of spill and formulate the plan of emergency responses. Excitation-emission matrix (EEM), which is also called three-dimensional fluorometric spectra, includes abundant spectral information in the domain of excitation wavelength and can be potentially applied to identify oil types. UV-induced fluorometric experiments were conducted in this study to collect EEMs for five types of oil that are commonly used in maritime transportation. A deep convolutional neural network (CNN) model for oil types identification was built based on the classic VGG-16 model. According to the identification results, the model was able to provide a reasonable classification on the five types of oil used in the experiments. Additionally, a biased classification result was observed in the experiment: the model was able to provide the most accurate classification on 0W40 lubricant but encounters difficulty distinguishing between − 10# diesel and 92# gasoline. The potential reasons for this result and the approaches to improve the model were also discussed.
Afficher plus [+] Moins [-]Hyperspectral characterization and chlorophyll content inversion of reclaimed vegetation in rare earth mines Texte intégral
2022
Li, Hengkai | Zhou, Beibei | Xu, Feng | Wei, Zhian
The special physical and chemical properties of the reclaimed land caused by the disturbance of rare earth mining and the environmental stress caused by the mining of rare earth lead to the inhibition of the physiological functions of the reclaimed vegetation and the severe challenge of vegetation ecological restoration. This study focuses on the Lingbei rare earth mining area in Dingnan County, Jiangxi Province, and investigates the original spectrum, derivative spectrum, and the continuum-removed spectrum of reclaimed vegetation. The spectral characteristics and trends and the typical reclaimed vegetation are analyzed, the correlation between the chlorophyll content and the spectral indices of the reclaimed vegetation is determined, and the sensitive spectral parameters are extracted. Partial least squares algorithm, a back propagation neural network algorithm, and a sparse autoencoder network are used to estimate the chlorophyll content, and the model’s accuracies are compared. The vegetation spectrum of the reclaimed vegetation is characterized by high reflectance in the visible region, a redshift of the green peak and red valley positions, and a blueshift of the red edge positions, a relatively low spectral variation in. The variability of the sensitive spectral parameters of different vegetation type is extracted. The sparse autoencoder network is the optimal estimation model (the R² value of the three vegetations are 0.9117, 0.7418, and 0.9815, respectively). The results provide a scientific basis for monitoring and managing the growth of different types of reclaimed vegetation in rare earth mining areas under environmental stress and can guide the ecological restoration of reclaimed mining areas.
Afficher plus [+] Moins [-]Molecular insight into the diffusion/flow potential properties initiated by methane adsorption in coal matrix: taking the factor of moisture contents into account Texte intégral
2022
Zhu, Hongqing | Zhang, Yilong | Liao, Qi | Hu, Lintao | Gao, Rongxiang | Qu, Baolin
Coal seam permeability is one of the key parameters affecting coalbed methane (CBM), and plays an important role in resource evaluation and regional selection. To fully explore the diffusion/flow potential properties initiated by methane adsorption beneath diverse moisture contents (1–5%) in coal molecules. The pore size distribution and methane adsorption capacities were discussed based on Monte Carlo (MC) and molecular dynamics (MD) methods. The potential properties of diffusion/flow induced by methane adsorption were investigated using the maximum absolute adsorption capacities as benchmark. The variation patterns of the pore structure were analyzed using SEM scanning experiment to verify the results of simulation analysis. It is found that the free pores facilitate methane molecular adsorption and increase adsorption spaces; the skeleton pores restrict the flow and transport of water molecules. Reduction values in surface free energies increase at different temperatures, and released heat diffusion coefficients and permeabilities for methane molecules drop as moisture contents increase. Interestingly, however, enhancements in temperatures increase the methane molecular diffusion coefficients. The lower the activation energies, the easier they are to diffuse. Sufficiently, the optimum conditions for gas drainage of coal seam are at temperature of 293K and moisture content of 5%, indicating greater contributions to gas pressure relief for coal seam. By comparing the results of molecular simulation and SEM scanning, trend of change is basically the same. Moreover, it is explored that hydraulic measure was the most significant to the CBM stimulation technology through field engineering application. This research is expected to provide guidance for facilitating the effectiveness of gas extraction for coal seam.
Afficher plus [+] Moins [-]Gender differences in trace element exposures with cognitive abilities of school-aged children: a cohort study in Wujiang city, China Texte intégral
2022
Wang, Yihong | Wang, Yaqian | Yan, Chonghuai
Trace elements persist in the environment, and their early exposure may adversely affect children's intellectual development. To clarify the influence of blood trace element levels in newborns and school-aged children, we used Wechsler Intelligence Scale for children (WISC-CR) to explore intellectual development level of 148 school-aged children based on a population cohort study. Lead (Pb), selenium (Se), arsenic (As), copper (Cu), manganese (Mn) and chromium (Cr) in cord blood and Pb, As, Cu in venous blood were determined by inductively coupled plasma mass spectrometry (ICP-MS) and atomic absorption spectrometer (AAS). Our analysis of the correlation between children's mental development and trace element content found children’s cognitive abilities negatively correlate with Pb (PIQ: β=-0.109, P=0.03737) and Cu (PIQ: β=-0.031, P=0.04431; FISQ: β=-0.031, P=0.02137) levels in cord blood. Prenatal low-level As exposure may negatively affect girls’ performance intelligence quotient (PIQ) and verbal intelligence quotient (VIQ). There were differences in Se levels in cord blood and venous blood between boys and girls (P=0.010; P=0.073). High Se levels were associated with a lower VIQ in boys and a higher VIQ in girls. Prenatal exposure to Pb, As and Cu may weaken children’s cognitive abilities at school age. Se exposure may have opposite effects on cognitive abilities affected by dose and gender.
Afficher plus [+] Moins [-]Experimental investigation on dish solar distiller with modified absorber and phase change material under various operating conditions Texte intégral
2022
Felemban, Bassem F. | Essa, Fadl Abdelmonem | Afzal, Asif | Ahmed, Mohamed Hamza | Saleh, Bahaa | Panchal, Hitesh | Shanmugan, Sengottiyan | Elsheikh, Ammar | Omara, Zakaria Mohamed
The shortage of potable water is a global problem. One of the techniques used to participate solving this problem is the solar distiller. The main demerit of solar distiller is its low output yield. So, this work aims at improving the freshwater productivity of a dish solar distiller by enlarging its absorber surface area and increasing its evaporation rate. As a result, the effect of using three different shapes of absorber liner was investigated: convex dish absorber, stepped absorber, and corrugated surface over the stepped absorber. In addition, the absorber of dish distiller was covered by a cotton wick to enlarge the wetted surface area. Also, different water depths (1.0, 2.0, 3.0, 4.0, and 5.0 cm) in dish distiller with stepped absorber were investigated. Moreover, the distance below basin liner was occupied by energy storing medium (paraffin wax + titanium oxide nanoparticles). The performances of dish distiller, dish distiller with stepped absorber, and dish distiller with corrugated absorber were evaluated and compared to that of a conventional solar distiller. Experimental results revealed that the performance of dish distiller with corrugated absorber, wick, and energy storing material was higher than that of dish distiller with stepped absorber, which was better than that of dish distiller, which was higher than that of conventional distiller. As well, the highest improvement in productivity of dish distiller with stepped absorber was 125% compared to conventional distiller and took place at 2-cm water depth. In addition, the productivity of dish distiller with corrugated absorber and wick was improved by 160% compared to that of conventional distiller. Additionally, the highest performance was obtained for dish distiller with corrugated absorber, wick, and energy storing material, where the productivity was augmented by about 183%, and the thermal efficiency reached 69.5%.
Afficher plus [+] Moins [-]Caveolar disruption with methyl-β-cyclodextrin causes endothelium-dependent contractions in Wistar rat carotid arteries Texte intégral
2022
Albrakati, Ashraf
Caveolae are organizing centers for cellular signal transduction in endothelial cells (ED) and smooth muscle cells (SMCs) in the blood vessels. Myography was used to investigate the effects of a caveolar disruption using methyl-β-cyclodextrin (MBCD) on maxi-K channels in rat carotid arteries. Incubation of carotid segments with MBCD augmented contractions in response to BaK (chemical channel agonist) but not those induced by depolarizing high potassium physiological saline (KPSS). In contrast, incubation with cholesterol-saturated MBCD (Ch-MBCD) abolished the effects of MBCD. Mechanical removal of endothelial cells by MBCD triggered a small contraction in response to BaK. Incubation with nitroarginine methyl ester (L-NAME) inhibited nitric oxide (NO) release, causing increased contractions in response to BaK, and this effect was reversed by pretreatment with MBCD. These results suggest that MBCD inhibits endothelial NO release. Contrastingly, inhibition of maxi-K channels with iberiotoxin enhanced contractions in response to BaK. Likewise, L-NAME decreased the contractile effect of iberiotoxin, as in the ED-denuded arteries. Transmission electron microscopy (TEM) showed the presence and absence of caveolae in intact blood vessels before and after MBCD treatment, respectively, whereas histology confirmed ED removal after the treatment. Caveolar disruption using MBCD impairs ED-dependent relaxation by inhibiting the release of NO from the ED and altered the contractility of SMCs independent of the ED due to reduced contribution of maxi-K channels to the SMC membrane potential, causing depolarization and increasing carotid artery contraction. These findings might help to understand the physiological role of the maxi-K channels in rat carotid arteries.
Afficher plus [+] Moins [-]The role of green innovations, environmental policies and carbon taxes in achieving the sustainable development goals of carbon neutrality Texte intégral
2022
Wang, Xinyu | Khurshid, Adnan | Qayyum, Sadia | Calin, Adrian Cantemir
The green innovations, environmental policies, and carbon taxes are the tools to achieve sustainable development goals (SDGs) in the mitigation process. This study is intended to examine the impact of innovation, carbon pricing (CTAX), environmental policies (EP), and energy consumption (ECON) on PM₂.₅ and greenhouse gas (GHG) emission for Central-Eastern European countries. The panel effect during 2000–2018 is tested using a dynamic panel data model while the Granger causality approach obtains country-related outcomes. The outcomes reveal that eco-friendly innovations have a more profound effect on carbon mitigation. Environmental policies reduce emissions by 2.7% in the short run and 17.4% in the long run. Similarly, CTAX mitigates GHG emissions by 8.6% in the short-run and PM2.5 by 0.9% and 5.7% in the short and long run. However, urbanization, energy consumption and trade openness are the leading polluters in the region. The main findings remain dominant in the country-specific results and find unidirectional and bidirectional causality evidence among variables. The research concludes that green innovations and strict environmental policy can lead towards achieving sustainable development goals using carbon taxes as a tool on the way.
Afficher plus [+] Moins [-]Rapid and sensitive detection of Karenia mikimotoi by loop-mediated isothermal amplification combined with a lateral flow dipstick Texte intégral
2022
Han, Xiaotian | Zhao, Ting | Yan, Tian | Yu, Rencheng
Harmful algal blooms frequently occur in various coastal regions worldwide, deteriorating marine ecology and causing huge economic losses. Therefore, developing a potential method for rapid detection of harmful algae species is highly necessitated. In this study, a loop-mediated isothermal amplification (LAMP) method coupled with a lateral flow dipstick (LFD) was developed for detecting the harmful algae Karenia mikimotoi. In this method, the internal transcribed spacer (ITS) sequence of K. mikimotoi was used as the template, and the corresponding specific primers were designed by the online software PrimerExplorer V5. Biotin was labeled on the 5′ end of forward inner primer (FIP), and the LAMP reaction was performed under the determined optimal conditions of 63℃ and 60 min. The lowest concentration of K. mikimotoi DNA tested using LAMP was 3.3 × 10–¹ pg/μL. Additionally, a 6-FAM-labeled probe was designed and displayed on the LFD after hybridization of the amplified product with the probe. The results demonstrated that LAMP-LFD could be a promising approach for detecting and monitoring harmful algae due to its high sensitivity and specificity.
Afficher plus [+] Moins [-]PM2.5 decadal data in cold vs. mild climate airports: COVID-19 era and a call for sustainable air quality policy Texte intégral
2022
Rangel-Alvarado, Rodrigo | Pal, Devendra | Ariya, Parisa
Airports are identified hotspots for air pollution, notably for fine particles (PM₂.₅) that are pivotal in aerosol-cloud interaction processes of climate change and human health. We herein studied the field observation and statistical analysis of 10-year data of PM₂.₅ and selected emitted co-pollutants (CO, NOₓ, and O₃), in the vicinity of three major Canadian airports, with moderate to cold climates. The decadal data analysis indicated that in colder climate airports, pollutants like PM₂.₅ and CO accumulate disproportionally to their emissions in fall and winter, in comparison to airports in milder climates. Decadal daily averages and standard errors of PM₂.₅ concentrations were as follows: Vancouver, 5.31 ± 0.017; Toronto, 6.71 ± 0.199; and Montreal, 7.52 ± 0.023 μg/m³. The smallest and the coldest airport with the least flights/passengers had the highest PM₂.₅ concentration. QQQ-ICP-MS/MS and HR-S/TEM analysis of aerosols near Montreal Airport indicated a wide range of emerging contaminants (Cd, Mo, Co, As, Ni, Cr, and Pb) ranging from 0.90 to 622 μg/L, which were also observed in the atmosphere. During the lockdown, a pronounced decrease in the concentrations of PM₂.₅ and submicron particles, including nanoparticles, in residential areas close to airports was observed, conforming with the recommended workplace health thresholds (~ 2 × 10⁴ cm⁻³), while before the lockdown, condensable particles were up to ~ 1 × 10⁵ cm⁻³. Targeted reduction of PM₂.₅ emission is recommended for cold climate regions.
Afficher plus [+] Moins [-]Geochemistry and sedimentary photopigments as proxies to reconstruct past environmental changes in a subtropical reservoir Texte intégral
2022
Cardoso-Silva, Sheila | Mizael, Juliana Oliveira Soares Silva | Frascareli, Daniele | Figueira, Rubens César Lopes | Pompêo, Marcelo | Vicente, Eduardo | Moschini-Carlos, Viviane
Sediment cores were used to establish past environmental impacts associated with eutrophication, erosion and metal contamination in the subtropical Atibainha reservoir (São Paulo State, Brazil). We hypothesize that: (1) the levels of nutrients, determined by a spectrophotometric method, reflect the contributions of these elements over time and (2) changes in sedimentation rates, determined by ²¹⁰Pb geochronology, and metal flows, determined by ICP-AEOS, are related to anthropic activities. Stratigraphic changes in the analysed variables were used to divide the sediment cores into three intervals, according to PCA and cluster analysis (Euclidian distances, Ward’s method). Interval I, composed by the period prior to operation of the reservoir, was influenced by organic matter levels. Interval II, between 1967 and 1993 (PC2: 14.94% of the total variability), a period of minor impacts, was mainly influenced by Mn (eigenvalue of 0.71) and Zn (0.74). Interval III, which included sediment deposited between 1993 and 2015 (PC1: 60.28% of the total variability), was influenced by the highest levels of the pigments lutein (0.86), zeaxanthin (0.90) and fucoxanthin (0.65), together with total nitrogen (0.78) and sedimentation rate (0.91), suggesting changes in the phytoplankton community composition probably associated to the intensification of eutrophication and erosion processes. Despite the limitations of applying paleolimnological techniques in reservoirs and the use of pigments as proxies in regions with higher temperatures, it was observed that the anoxic conditions and the aphotic environment in the hypolimnion acted to preserve pigments associated with the groups Chlorophyta (lutein), Cyanobacteria (zeaxanthin) and Bacillariophyta (fucoxanthin). The isolated analysis of nutrients was not sufficient to make conclusive inferences regarding the eutrophication history, since the levels of TP tended to decrease over time, in contrast to an increase in the levels of TN. Despite intensification of eutrophication and erosion, associated to anthropic activities, no signs of metal contamination were recorded.
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