查看更多>>摘要：Abstract Previous studies have examined the relationship between total e-waste generation and its determinants. However, e-waste categories have not received appropriate attention, and thus important information is missing for policymakers. This paper advances the state of knowledge by studying e-waste categories individually. Statistical data of e-waste in the EU28?+?2 countries over the period 2000–2015 is disaggregated into single categories, namely temperature exchange equipment, screens and monitors, lamps, large equipment, small equipment, and small IT and telecommunication equipment. To examine the main driving forces of e-waste in each category, the STIRPAT model (Stochastic Impacts by Regression on Population, Affluence, and Technology) and the environmental Kuznets curve (EKC) hypothesis are applied, using panel quantile regression as main method and pooled OLS to control robustness of findings. Results show that population, renewable energy consumption, trade openness, and urbanization are positively correlated with all e-waste categories. Renewable energy exploitation is a major e-waste driver of large and small equipment, screens and monitors, and small IT. Interestingly, an inverted U-shaped relationship between gross domestic product (GDP) per capita and the quantity of e-waste was found across all e-waste categories for most regressions when using the quantile regression method (28 out of 30 quantiles), and for all regressions when using the pooled OLS method. This confirms the EKC hypothesis and indicates that e-waste of all categories increases with GDP up to a certain level (turning point) but then decreases when GDP continues to grow.
查看更多>>摘要：Abstract In situ radioactivity measurements were performed to describe and map the relationship between the radioactive concentration distribution on the surface and geological formations in the Karadeniz Technical University (KTU) campus and surrounding area located on the shore of the Black Sea in NE Turkey. The concentrations of radio-elements (eU, eTh, and K) and dose rate values were measured using a portable gamma-ray spectrometer with NaI(Tl) crystal at 150 points in the study area with a duration of 5?min for each measurement point. In addition, the geochemical radio-element ratios (eTh/eU, K/eU, and eU/eTh) give information about the origin of the rocks, and radiological hazard parameters for humans and the environment were also calculated. Average values of eU, eTh, and K concentrations, and dose rate, were calculated to be 3.59?ppm, 13.46?ppm, 0.84%, and 65.38 nGy/h, respectively. While the highest concentrations of radio-element and dose rate values were recorded at outcrops of Eocene-Neogene basaltic rocks and red clays, which are the weathering product of the Kabak?y formation, the lower anomaly zones coincide with brown and reddish brown forest and agricultural soils of volcanic origin in the study area. According to the average radio-element ratios, it was concluded that the rocks in the study area do not completely originate from the crust, but formed as a result of the mixture of upper mantle and continental crust. All the calculated hazard parameters seem to be lower than the internationally recommended values, and there is no cancer risk in and around the campus area.
查看更多>>摘要：Abstract A fully automated isotopic profile deconvoluted chromatogram (IPDC) algorithm (Fakouri Baygi et al. in Anal Chem 91:15509–15517, 2019) and user interactive HaloSeeker 1.0 (Le?on et al. in Anal Chem 91:3500–3507, 2019) were compared to test the efficacy of these two computationally enhanced non-targeted screening (CENTS) tools in isolating unknown Br/Cl compounds using high-resolution mass spectrometry (HRMS) data. HaloSeeker depends on a user to monitor the performance of the peak picking algorithm and assign molecular formulas for each isotopic signature in an ergonomic interface. Alternatively, the IPDC algorithm automatically assigns and ranks candidate molecular formulas within a set of search criteria. Both CENTS tools were evaluated using fish and sediment data acquired at 22,000 (mHRMS) and >?100,000 (uHRMS) mass resolutions, respectively. The IPDC algorithm detected 85% of compounds detected by HaloSeeker as the first candidate compound in the sediment sample, with fewer false positives. In the sediment data, the IPDC algorithm detected several compounds such as clofoctol and chlorinated paraffins that were not reported using HaloSeeker 1.0. Upon further inspection, these compounds were isolated by the HaloSeeker program, but not reported by the user. HaloSeeker detected all significant and insignificant chemical ionization products (relative to IPDC), but additional false positives were isolated in the mHRMS polychlorinated biphenyl reference standard and trout sample. HaloSeeker detected 62% of the legacy contaminant features isolated by the IPDC algorithm in the fish data (mHRMS). The comparison of these two CENTS tools demonstrates that matrix complexity and mass resolution of the HRMS platform are the key factors when choosing automated and user interactive CENTS tools.
查看更多>>摘要：Abstract In a new approach, copper ferrite (CuFe2O4) nanoparticles were easily synthesized using a microwave-ignition reaction and then coated by extracted chlorophyll (extracted from mulberry green leaves) to amplify the photocatalytic and adsorption qualities. The FE-SEM, TEM, Raman, BET, VSM, XRD, EDX and FT-IR techniques were applied to analyze the structure and properties of CuFe2O4 and Chlorophyll/CuFe2O4. The average sizes for nano-catalysts were estimated about 90?nm for CuFe2O4 and 120?nm for Chlorophyll/CuFe2O4. A shift in the band gap from 1.45?eV for CuFe2O4 to 1.3?eV for Chlorophyll/CuFe2O4 exhibited an increase in photocatalytic performance of nanoferrites after coating by the chlorophyll molecules. Photocatalytic degradation studies were performed through UV–Vis technique to measure the removal content of methylene blue (MB) from aqueous samples. The removal efficiency for CuFe2O4 and Chlorophyll/CuFe2O4 were found to be 35.1% and 94.0%, respectively, at certain test conditions. Thereupon, the results confirmed that photocatalytic activity and decomposition capability to remove the MB contaminant increased considerably for chlorophyll coated ferrite. Finally, the nanoparticles were easily separated by an external magnet, reused for several times, and illustrated a negligible decrease in their activity after each cycle.Graphical abstract
Faisal A. A. H.Nassir Z. S.Rashid H. M.Al-Hashimi O. A....
14页
查看更多>>摘要：Abstract The current theoretical and experimental study was to thoroughly examine the capability of date stones for scavenging cadmium and lead ions from simulated wastewater. Three layers-artificial neural network (ANN) with 115 batch tests proved that the best conditions achieved the highest sorption efficiency (>63% for Cd(II) and?>?91% for Pb(II)) where time 1?h, pH 5–6, dosage 5?g/100?mL, speed 100?rpm and temperature 25?°C. A satisfactory matching between the measurements and the ANN outputs was recognized with coefficient of determination greater than 99%. The ANN has also revealed throughout the sensitivity analysis that the initial pH and contact time with importance of 25 and 39% for cadmium and lead ions respectively were considered to be the most influential parameters in the removal process. Among Langmuir, Freundlich, and ANN models, the latter one was well fitted the sorption data. This model was substituted in solute transport equation to describe the spatial and temporal distribution of metal ions through the packed column. From the breakthrough curves, the well agreement between the theoretical and measurements (Willmott’s index almost greater less than 0.97), the date stones sorbent have had greater tendency to sorb lead ions than that of cadmium ones.
El-Liethy M. A.El-Noubi M. M.Abia A. L. K.El-Malky M. G....
12页
查看更多>>摘要：Abstract Petroleum oil contaminants have become severe ecological problems and negatively impact human health. It is, therefore, imperative to identify environmentally friendly approaches to remediate oil-polluted environments. Therefore, bacterial oil degradation stimulated with a nitrogen source under optimum conditions was assessed in this study. Based on the 16S rRNA analysis, strain ODB H32 recovered from oil-based mud of some petroleum drilling sites in the western desert, Egypt, was identified as Enterobacter hormaechei. The metabolic fingerprint of E. hormaechei, achieved using BIOLOG GEN III, revealed that the strain could utilize diverse carbon and chemical sources. Also, E. hormaechei could biodegrade 0.6% of oil under optimized pH (7.0) and temperature (30?°C) conditions. Analyzing different nitrogen stimulants revealed that peptone ? yeast extract ? ammonium nitrate ? urea enhanced the growth of E. hormaechei on mineral salts medium (MSM). Analysis by capillary gas chromatography revealed maximum (70.7%) degradation of peptone by E. hormaechei, indicating that peptone was a good biostimulant for oil degradation. These findings recommend using biostimulated E. hormaechei as an eco-friendly approach for remediating oil-polluted environments, under optimized conditions, especially in arid regions like the western desert of Egypt.
de Carvalho Curi T. M. R.de Alencar N??s I.da Silva Lima N. D.Martinez A. A. G....
10页
查看更多>>摘要：Abstract The present study aimed to estimate the impact of global warming on Brazilian broiler production cost, giving the future scenarios presented by the International Panel on Climate Change using the fuzzy logic approach. The database included broiler production costs at normal temperature conditions (input), considering the need for investment for mitigating the increase in environmental temperatures. The output was the production cost change (PCV). We studied three housing technology levels directly related to the utilization of insulation, ventilation, and cooling equipment (Tech 1, 2, and 3). The analysis was divided into two aspects: the rise in air temperature, pessimistic (+?2.5?°C) and optimistic (+?1.5?°C). Fuzzy logic was applied using the Mamdani model. The fuzzy set was represented by the triangular membership function for the input and output variables, which presented lower standard deviation values. PCV functions were found for the studied scenarios for each housing technology. Under the pessimistic setup, the highest PCV (42.3%) was found for the medium-level housing technology (Tech 2), meaning that the farmer needs to invest more in the rearing environment to face global warming. A similar result was found for Tech 1 with a PCV of 35.8%. Under the optimist scenario, the smallest PCV was detected in the Tech 2 housing (12.5%), followed by the applied Tech 3 (19.9%). Results indicated that broiler farmers with a high degree of housing technologies are less vulnerable to extreme weather due to earlier investment in cooling technologies.
查看更多>>摘要：Abstract The intrusion of sea saltwater has destructive effects on freshwater resources as well as hydraulic structures. The first disastrous effect is reducing the volume of available freshwater storage and reducing available surface water quality. Various methods are used to prevent salinity intrusion into upstream river. One of the applied systems in reducing salinity intrusion in the mouth of rivers and especially in the shipping locks is the air bubbles curtain. For proper use of the air bubbles curtain system, it is necessary to determine the effect of different parameters on its performance. Therefore, in the present study, the effect of seawater density and air bubbles discharge on the performance of the air bubbles curtain was studied using a numerical model. The results show that the air bubbles curtain can prevent salinity intrusion by forming a vertical flow. Indeed, the air bubbles curtain's proper performance depends on the air bubbles discharge and the difference between saltwater and freshwater density. In other words, an increase in the density of seawater raises the salinity intrusion force and thus leads to the formation of a clockwise rotational flow upstream of the air bubbles curtain, which in turn intensifies the salinity intrusion into upstream of the air bubbles curtain and reduces the efficiency of the air bubbles curtain. Increasing air bubbles discharge culminates in preventing saltwater intrusion, although there is an optimal discharge that discharges greater than it has insignificant effects on air bubbles curtain performance.
查看更多>>摘要：Abstract Bentonite clay is most commonly used as a landfill liner but is resource-intensive and suffers drawbacks like large volume change and desiccation cracking. It also poses construction difficulties and the handling of a large volume of material. In situ soil can be successfully modified into base liners for landfills which offers an economical and sustainable alternative to bentonite liners. In this study, an exocellular biopolymer, xanthan gum, is used to improve the in situ soil and provides a novel alternative liner material. A comparative study is also made by modifying the in situ soil with various percentage of bentonite. The results show that the maximum dry density of the in situ soil increased marginally for both the additives. Hydraulic conductivity decreased from 2.87?×?10–3 to 4.46?×?10–8?cm/s at 1% xanthan gum addition while in case of bentonite it reduces to 4.81?×?10–8?cm/s at 30% addition. This significant reduction in hydraulic conductivity on stabilizing soil with xanthan gum is attributed to gel coating on the soil surface and gel plug formation in the soil matrix, confirmed by morphological studies. Choice of xanthan gum for stabilizing soil and modifying it into baseliners is economical than bentonite clay. The mechanism of bio-plugging in xanthan gum stabilized soil will also control leachate movement through the soil. Hence, xanthan gum, a renewable, sustainable and carbon negative biopolymer, can be successfully used to modify in situ soil into clay liner.Graphic abstract
查看更多>>摘要：Abstract Interior dust lead loadings on floors and windowsills are reliable predictors of a child’s blood lead level and an important predictor in “clearance testing” of residences. The portable X-ray fluorescence device is an alternate technique that can provide fast, accurate, and precise results regarding the presence of dust lead hazards in residences. In this paper, we tested the comparability of the portable X-ray fluorescence device against Inductively Coupled Plasma Mass Spectrometry, using the newer lead hazard standards for dust wipe samples. Dust wipe samples (n?=?109) collected from floors and interior windowsills of 13 homes were tested by means of a portable X-ray fluorescence device and subsequently analyzed for lead using Inductively Coupled Plasma Mass Spectrometry. Considering Inductively Coupled Plasma Mass Spectrometry as the “gold standard,” the portable X-ray fluorescence device produced an average false negative rate of 27.3% at the new dust lead hazard standards of 10?μg/ft2 for floors, and 100?μg/ft2 for windowsills. There were no false positive results from the portable X-ray fluorescence device at the new dust lead hazard standards. A Bland Altman analysis showed that 96.3% of the data points were within the lower and upper acceptable limits of agreement. The results of the study suggested that the portable X-ray fluorescence device has a good agreement with the Inductively Coupled Plasma Mass Spectrometry method at lower lead concentrations and is appropriate for measuring lead concentrations in field dust wipe samples from homes where lead concentrations are in a lower range.
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