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النتائج 3811 - 3820 من 7,291
Microplastics Locked in Water-Stable Aggregates of the Haplic Luvisol and Role of Land Use on Their Potential Mobility النص الكامل
2022
Klíč, Radek | Kravka, Miroslav | Wimmerová, Lenka | Viruez, Julio Leonardo Garcia | Válová, Marie | Miháliková, Markéta
Microplastics (MPs) have long been the subject of scientific articles dealing with environmental pollution. The purpose of this study was to determine the occurrence and amount of MPs in soil aggregates depending on land use. The soil in the research area was formed on loess parent material and classified as Haplic Luvisol. From the soil samples were determined particle size distribution curves, and subsequently 40 mixed samples were dry sieved and then wet sieved to determine the percentage of individual soil fractions of water-stable soil aggregates (WSA). The representation and number of MPs were determined for the most common fractions. It was found that MPs occur in both cases of land use, slightly more (62 pt/5 g) in forest soil compared to arable (40 pt/5 g). It is generally known that soil is not homogeneous, but the amount of MPs in top layer for arable soil (8000 pt/kg) and forest (12,400 pt/kg) was estimated. The effect of land use is that forest WSA have a larger mean weight diameter (MWD) than arable land. By being larger, they are also more stable to movement during water erosion. MPs are bound in soil aggregates and they move together with them. This can be deduced from our measurements, because MPs extracted from WSA do not disintegrate in water after 2 hours and even after subsequent wet sieving. The effect of land use on microplastic occurrence and movement should be continually of concern in the future.
اظهر المزيد [+] اقل [-]The cardiotoxicity of asthmatic rats after traffic-related PM2.5 and water-soluble components exposure mediated by endoplasmic reticulum stress and autophagy النص الكامل
2022
Tian, Jiayu | Shi, Hao | Wang, Xin | Zhending, | Wang, Caihong | Liu, Nannan | Wang, Dan | Shi, Dongxing | Zhang, Hongmei | Zhang, Zhihong
Fine particulate matter (PM₂.₅) is closely related to cardiopulmonary diseases; it is known that the respiratory system is related to the cardiovascular system. This study aimed to investigate the toxic effects of traffic-related PM₂.₅ (TRPM₂.₅) and water-soluble components (WSC) on hearts of asthmatic rats and explore potential molecular mechanisms. Here, ovalbumin (OVA)-sensitized asthmatic rats were intratracheally instilled with TRPM₂.₅ and WSC every 3 days in total of eight times. Significant myocardial pathological changes were observed in the TRPM₂.₅ and WSC group by hematoxylin-eosin (HE) staining. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) results demonstrated TRPM₂.₅ and WSC aggravated apoptosis of myocardial cells, which may be triggered by endoplasmic reticulum stress (ERS), as manifested by elevated GRP78, CHOP, and caspase-12. Likewise, TRPM₂.₅ and WSC activated autophagy via upregulation of LC3 and p62 gene and protein expression. In conclusion, TRPM₂.₅ and WSC may aggravate heart injury in asthmatic rats, possibly through the activation of ERS and autophagy signaling pathway.
اظهر المزيد [+] اقل [-]Mix-method modelling of actors’ capacity for environmental sustainability and climate compatible development in energy sector النص الكامل
2022
Javed Iqbal, Kanwar Muhammad | Akhtar, Nadia | Khan, Muhammad Owais | Khan, Muhammad Irfan
The development of the energy sector has played a major role in greenhouse gas (GHG) emissions and pollution. The situation thus necessitates rigorous actions for climate compatible development (CCD). The energy sector is context-dependent, due to which response strategies for CCD are quite challenging particularly in the context of energy crises and the actors’ capacity issue in developing countries. This study was aimed at exploring the role of government actors involved in governing the energy sector, with the objective to assess their capacity using a set of principles, criteria, and indicators (PCIs). The study attempted to answer the question: is the capacity of the line departments involved in energy governance adequate to achieve the targets set under SDG-7 and SDG-13? For this purpose, the study employed a combination of “Rules-based” and “Rights-based” governance approaches at all tiers of governance, i.e., federal, provincial, and district levels. Actors’ capacity was assessed by developing a governance index based on the scoring of PCIs. Three hundred forty key informant interviews (KIIs) and 17 focus group discussions (FGD) were conducted at federal, provincial, and district levels where respondents were asked to score each of the indicators. Responses were then statistically analyzed and validated. The findings revealed that departments at the federal level are playing an effective role and are adequately equipped to align SDG-7 and SDG-13 with energy sector development. However, departments at the provincial and district levels are still lagging behind to achieve the desired objectives, which demonstrate the need to enhance the capacities of provincial and district line departments.
اظهر المزيد [+] اقل [-]Copper recovery by cementation process from polymeric membrane concentrate flows and sensor integration النص الكامل
2022
Koseoglu, Hasan | Delikanli, Niyazi Erdem | Gonulsuz, Ece | Aydin, Muhammed Talha | Sardohan Koseoglu, Tugba | Yigit, Nevzat Ozgu | Harman, Bilgehan Ilker | Kitis, Mehmet
In this study, copper recovery and sensor integration for concentrate flows of membrane processes were studied. In the first phase, cementation tests for copper recovery were carried out with various different Fe/Cu stoichiometric ratios, copper concentrations, temperatures, and stirring speeds. The effects of the parameters which were stirring speed, temperature, stoichiometric ratio, and concentration in the solution on the cementation process were determined. In the second phase, a novel electroanalytical sensor was applied to concentrate flow. The application of cementation within the scope of precious metal recovery from concentrate streams by integrating a sensor to the process as an innovative online-sensing-approach is conducted. Four different copper concentrations (64, 128, 512, 1280 mg/L) and 5 different Fe/Cu stoichiometric ratios for these concentrations were studied. For concentrations of 64 mg/L and 128 mg/L, 1/1, 2/1, 5/1, 7/1, 10/1 Fe/Cu ratios and for both 512 mg/L and 1280 mg/L concentrations, 1/1, 1.25/1, 1.5/1, 1.75/1, 2/1 Fe/Cu ratios were applied. The cumulative average of ICP-MS linearity of developed electroanalytical sensor was 94.9%. The efficient recovery of copper from the concentrate flows with the sensor integrated-cementation process has a strong potential for “Industry 4.0” applications with enhanced automation levels.
اظهر المزيد [+] اقل [-]Can China’s carbon emissions trading scheme achieve a double dividend? النص الكامل
2022
Ma, Qian | Yan, Guang | Ren, Xiaohang | Ren, Xiaosong
To ensure the realization of carbon neutrality and emission peak, the Chinese government promulgated the pilot policy for an emissions trading scheme (ETS) in 2011 and gradually expanded the range of the pilot program. However, it has not been systematically studied whether this policy can achieve double dividend and its transmission mechanism. Based on the Porter hypothesis, this paper explores the impacts of an ETS on macro emission reduction and microeconomic performance, verifies the influence of an ETS on double dividend, and analyzes its transmission mechanism using a difference in difference (DID) model and mediation model. The results indicate that an ETS can reduce CO₂ emissions and remarkably improve the economic performance of the enterprises in the areas it is enacted. A double dividend has been realized, which verifies Porter’s hypothesis. The mechanism test shows that from the macro perspective, the emission reduction effect of an ETS is mainly achieved by adjusting the energy structure and through local government regulations. In contrast, the mediation effect on the industrial structure is not apparent. From a micro perspective, an ETS mainly affects the economic situation of enterprises through cash flow and technological innovation. Moreover, the transmission effect of enterprises’ low-carbon behavior is not apparent. Heterogeneity analysis shows that compared with Midwestern China, an ETS could reduce emissions by adjusting the energy structure in Eastern China. Also, compared with state-owned or large enterprises, an ETS helps improve the economic performance of small or non-state-owned enterprises through technological innovation. This paper provides empirical evidence from macro- and microperspective for evaluating an ETS, conducive to improving the top-level framework of China’s future carbon market operation.
اظهر المزيد [+] اقل [-]Assessment of groundwater vulnerability and pollution risk using AVI, SPI, and RGPI indexes: applied to southern Gabes aquifer system, Tunisia النص الكامل
2022
Atoui, Mounir | Agoubi, Belgacem
Southern Gabes aquifer is part of coastal Jeffara plain located in southeastern Tunisia. It consists a semi-arid area in which groundwater is the main source to water supply for several socio-economic sectors. Southern Gabes aquifer suffers from excessive abstraction and heavy anthropogenic pressures that make local groundwater resources threatened by pollution risks. This study aims to assess groundwater vulnerability, evaluate, and delineate groundwater risk regions. For this, a 17 water samples were carried out in the study area and chemical compositions were analyzed. A well-known AVI model has been used to assess aquifer vulnerability and new algorithms of sensitivity to pollution index (PSI) and risk groundwater to pollution index (RGPI) were implemented and used to assess, classify, and map groundwater pollution risk. Results reveal that study area suffers from high risk. Forty one percent of the total surface of study area has a very high risk. Nonetheless, only 30% of study area has a low to insignificant risk to pollution which necessitates taking severe precautions to protect the southern Gabes aquifer system. The method used in this study seems giving more precise results compared to conventional approaches. Moreover, this method allows assessing the pollution risk with flexible and reliable algorithm even with limited dataset. Hence, the poor natural protective capacity of study area needs a rapid intervention by local authorities in order to develop proactive solutions to protect and preserve groundwater resources from pollution risks and establish a long-term program for groundwater resources sustainable development.
اظهر المزيد [+] اقل [-]Performance analysis of a solar dryer integrated with thermal energy storage using PCM-Al2O3 nanofluids النص الكامل
2022
Subramaniam, Babu Sasi Kumar | Sugumaran, Arun Kumar | Athikesavan, Muthu Manokar
Solar energy will assist in lowering the price of fossil fuels. The current research is based on a study of a solar dryer with thermal storage that uses water and waste engine oil as the working medium at flow rates of 0.035, 0.045, and 0.065 l/s. A parabolic trough collector was used to collect heat, which was then stored in a thermal energy storage device. The system consisted of rectangular boxes containing stearic acid phase change materials with 0.3vol % Al₂O₃ nanofluids, which stored heat for the waste engine oil medium is 0.33 times that of the water medium at a rate of flow of 0.035 l/s which was also higher than the flow rates of 0.045 and 0.065 l/s. The parabolic trough reflected solar radiation to the receiver, and the heat was collected in the storage medium before being forced into circulation and transferred to the solar dryer. At a flow rate of 0.035 l/s, the energy output of the solar dryer’s waste engine oil medium and water was determined to be roughly 12.4, 14, and 15.1, and 9.8, 10.5, and 11.5 times lower than the crops output of groundnut, ginger, and turmeric, respectively. The energy output in the storage tank and the drying of groundnut, ginger, and turmeric crops with water and waste engine oil medium at varied flow rates of 0.035, 0.045, and 0.065 l/s were studied. Finally, depending on the findings of the tests, this research could be useful in agriculture, notably in the drying of vegetables.
اظهر المزيد [+] اقل [-]Assessment of goethite-combined/modified biochar for cadmium and arsenic remediation in alkaline paddy soil النص الكامل
2022
Abdelrhman, Fatma | Gao, Jieyu | Ali, Umeed | Wan, Neng | Hu, Hongqing
The opposed transformation of arsenic (As) and cadmium (Cd) in paddy soil postures numerous challenges for their simultaneous remediation. An incubation study was conducted on the immobilization of Cd and As by biochar (BC), goethite (G), goethite-combined biochar (BC + G), and goethite-modified biochar (GBC). The results showed that biochar effectively immobilized Cd while significantly increasing As mobility, whereas goethite effectively immobilized As more than Cd. BC + G treatment significantly decreased toxicity characteristics leaching procedure (TCLP) and CaCl₂-extractable Cd by 22.70% and 40.15%; meanwhile, TCLP and NaHCO₃-As were significantly reduced by 38.25% and 31.87%, respectively, compared with the control. This study found that GBC was the optimum amendment within the immobilization efficiency for CaCl₂-Cd (57.03%) and TCLP-As (61.11%). BC + G and GBC applications showed some interactions between biochar and goethite, which played an essential role in immobilizing Cd and As simultaneously. Therefore, GBC showed a great benefit in being a low-cost and efficient environmental amendment for Cd and As remediation in alkaline co-contaminated paddy soil.
اظهر المزيد [+] اقل [-]COVID-19 pandemic and sudden rise in crop residue burning in India: issues and prospects for sustainable crop residue management النص الكامل
2022
Ravindra, Khaiwal | Singh, Tanbir | Mor, Suman
The seasonal burning of crop residue significantly affects the environment, leading to poor air quality over Indo-Gangetic Plain (IGP) in India. Hence, there have been significant efforts to minimize crop residue burning through policy, innovations, and awareness measures. However, an abrupt increase in paddy residue burning was observed over IGP during 2020. Hence, the study explores the factors leading to this sharp rise. The business as usual trends analysis revealed that paddy crop residue burning activities increased significantly (60%) in 2020 compared to the previous year. The massive increase in crop residue burning consequently seems to be linked with the COVID-19 pandemic, which affected the farmer’s income, including the poor compliance by the regulatory authorities. The study also highlights the issues and prospects for sustainable crop residue management and explores the solutions to minimize crop residue burning. There are few crops in India that have guaranteed minimum sale price and are also subsidized. These provisions encourage farmers to grow those particular crops, resulting in the generation of large amounts of crop residue from these specific crops. There have been several efforts by the Indian government, including based on recent court intervention. Still, there is no respite from burning activities and the occurrence of Delhi winter smog every year. Hence, the study emphasizes a need to adopt integrated approaches having in situ eco-friendly solutions, which enhances the farmer’s income and focuses on employability, capacity building, awareness generation, and in situ economically viable solutions.
اظهر المزيد [+] اقل [-]Herding Oil Slicks with Fatty Alcohol and Carbonaceous Particles النص الكامل
2022
Earnden, Laura | Foster, Sierra Eckel | Tchoukov, Plamen | Stoyanov, Stanislav R. | Pensini, Erica
Oil slicks occurring during petroleum transportation or production are major sources of surface water pollution, and spread over large areas. Herders are interfacially active species that reduce the spread of oil slicks on water surfaces, facilitating slick recovery. Here, octanol (a readily biodegradable fatty alcohol) is used as a herder to facilitate the recovery of diluted bitumen and conventional crude oil spilled onto the surface of fresh and synthetic marine water. While octanol promptly decreases the area of simulated oil slicks in Petri dishes, over time it partitions into the oil phase and lowers its interfacial tension. As a result, low-viscosity hydrocarbons (toluene and conventional crude oil) re-spread. This study uses charcoal to suppress re-spreading and facilitate the mechanical recovery of oil slicks. Charcoal partitions into the crude oil phase and does not stabilize crude oil in water emulsions upon mixing, as demonstrated using optical microscopy. This ensures that charcoal particles are not lost to the water phase and do not promote hydrocarbon dispersion. Charcoal prevents herded slicks from re-expanding by rigidifying the crude oil–water interface (demonstrated using a Langmuir trough) and potentially due to the affinity of crude oil for charcoal. Therefore, charcoal facilitates the physical removal of crude oil slicks after herding, as qualitatively assessed by retrieving them from Petri dishes with the aid of a spatula. While charcoal also facilitates the recovery of herded low-viscosity conventional crude oil, it has only a marginal effect on the recovery of herded bitumen, which has high viscosity.
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