Search

This study examines the intensifying threat to public health caused by increased CO2 emissions from energy and modern urbanization. In this connection, we focused on SAARC countries from 1990 to 2022. The study explores the dynamic association among urbanization, CO2 emissions, renewable energy, and key health indicators, namely life expectancy and infant mortality. It offers nuanced insights by highlighting the requirement for sustainable policies to meet health challenges associated with CO2 emissions and urban development in SAARC economies. To achieve the study objectives, the authors utilized panel auto regressive distributed lag for assessing short‐term and long‐run effects, and the method of moments quantile regressions to check these effects across different quantiles. The empirical results underscore the positive impact of renewable energy, urbanization, GDP, and industrialization on life expectancy. Conversely, CO2 emissions exhibit a detrimental impact on life expectancy, leading towards numerous diseases in both the short and long term. Notably, in the case of infant mortality, the study discloses that renewable energy, urbanization, GDP, and industrialization negatively affect infant mortality, while CO2 emissions positively impact infant mortality in both short and long‐run scenarios. Fully modified ordinary least squares and dynamic ordinary least squares further fortified our findings, supporting the results derived from panel auto regressive distributed lag and method of moments quantile regressions. The study's policy implications highlight the imperative for governments and policymakers to prioritize renewable energy and sustainable urbanization, mitigating the adverse health effects of CO2 emissions from non‐renewable energy sources. The study's findings further endorse a strategic shift towards renewable energy sources, positioning them as substitutes for conventional forms such as fossil fuels. Additionally, the emphasis is on planned and sustainable urbanization, facilitating improved access to health facilities and overall public health. [ABSTRACT FROM AUTHOR]

Increasing studies have highlighted that the remarkable inherent uncertainty in design flood hydrograph (DFH) can potentially undermine flood management decisions. In order to quantitatively trace the propagation of DFH uncertainty in reservoir flood control system, we propose a novel methodological framework including three corn parts. First, a copula-based DFH estimation model integrating Bayes' theorem is presented to estimate DFH under model parameter uncertainty. Second, we perform an optimal reservoir operation model for flood control (OROM FC) with uncertain DFH as input variable to derive reservoir flood control operations (i.e. output variable). Third, an information theory-based model is designed to trace the DFH uncertainty propagation in reservoir flood control system. A reservoir flood control system in the Han River basin in China is selected as case study. Related results indicate that uncertainty in reservoir flood control operations reduces in comparison with the remarkable uncertainty in DFH due to the performance of the OROM FC. Specifically, uncertainty in reservoir flood control operations in periods close to peak flow is much smaller compared with that in other periods. The phenomenon further highlights the importance of reservoir flood control operations during periods prior to peak flow. Additionally, we find that uncertainty in flood peak of DFH is the dominant factor affecting reservoir flood control operations compared with that in flood volume of DFH. Moreover, we explore the impact of reservoir flood control capacity on reservoir flood operations in the context of DFH uncertainty. An interesting linear expression is found and fitted for identifying design flood events inducing reservoir overtopping under specific reservoir flood control capacity. • The uncertain design flood hydrographs (DFH) are obtained through a copula-based model integrating Bayes' theorem. • An information theory-based approach is designed to perform uncertainty quantification and propagation analysis. • Uncertainty in reservoir flood control operations reduces in comparison with the remarkable uncertainty in DFH. [ABSTRACT FROM AUTHOR]

• A bootstrap-based algorithm is proposed for disclosing uncertainty of Budyko model. • Propagation of the parameter uncertainty to water availability assessment is derived. • There exists remarkable uncertainty in parameter w of Budyko model. • Impact of w uncertainty on Budyko output varies nonlinearly with climate. Parametric Budyko method has been widely used to assess water availability under changing environment. Its single parameter (w) controlling the shape of the Budyko curve, is of critical importance to water availability assessment (WAA). Here, the water availability is defined as the ratio of evapotranspiration to precipitation in the context of Budyko hypothesis. As an unobserved variable, w is generally estimated through incorporating the long-term water-balance model and Budyko hypothesis, i.e. estimating w as a function of precipitation, runoff, and potential evapotranspiration over a long-term time series of these variables. Inevitably, the estimated value of w is subject to uncertainty resulting from hydro-meteorological records with limited size. Further, this uncertainty affects WAA in context of Budyko hypothesis. The uncertainty and its propagation issue is often overlooked in past research. In this paper, we develop a bootstrap-based algorithm to reveal aforementioned uncertainty. Moreover, a partial derivative-based sensitivity analysis is performed for understanding the propagation of w uncertainty on WAA. Three catchments located in the Yellow River Basin, China, are used as case study sites. Results indicate that there exists remarkable uncertainty in parameter w , which varies with the data length. The impact of such uncertainty on WAA increases quickly under the humid condition, thereafter reaches a peak under the mild condition, and decreases slowly under the arid condition. The reason behind this phenomenon is the largest sensitivity of WAA to parameter w under the mild climate condition. Moreover, a general analytical expression for determining the critical value of climate condition which maximizes the impact of parameter w uncertainty on WAA is derived in this paper. Results of this study can enhance the reliability and robustness of Budyko-based models. [ABSTRACT FROM AUTHOR]

Floods have changed in a complex manner, triggered by the changing environment (i.e., intensified human activities and global warming). Hence, for better flood control and mitigation in the future, bivariate frequency analysis of flood and extreme precipitation events is of great necessity to be performed within the context of changing environment. Given this, in this paper, the Pettitt test and wavelet coherence transform analysis are used in combination to identify the period with transformed flood-generating mechanism. Subsequently, the primary and secondary return periods of annual maximum flood (AMF) discharge and extreme precipitation (Pr) during the identified period are derived based on the copula. Meanwhile, the conditional probability of occurring different flood discharge magnitudes under various extreme precipitation scenarios are estimated using the joint dependence structure between AMF and Pr. Moreover, Monte Carlo-based algorithm is performed to evaluate the uncertainties of the above copula-based analyses robustly. Two catchments located on the Loess plateau are selected as study regions, which are Weihe River Basin (WRB) and Jinghe River Basin (JRB). Results indicate that: (1) the 1994-2014 and 1981-2014 are identified as periods with transformed flood-generating mechanism in the WRB and JRB, respectively; (2) the primary and secondary return periods for AMF and Pr are examined. Furthermore, chance of occurring different AMF under varying Pr scenarios also be elucidated according to the joint distribution of AMF and Pr. Despite these, one thing to notice is that the associate uncertainties are considerable, thus greatly challenges measures of future flood mitigation. Results of this study offer technical reference for copula-based frequency analysis under changing environment at regional and global scales. [ABSTRACT FROM AUTHOR]

Traditional flood risk analysis focuses on the probability of flood events exceeding the design flood of downstream hydraulic structures while neglecting the influence of sedimentation in river channels on regional flood control systems. This work advances traditional flood risk analysis by proposing a univariate and copula-based bivariate hydrological risk framework which incorporates both flood control and sediment transport. In developing the framework, the conditional probabilities of different flood events under various extreme precipitation scenarios are estimated by exploiting the copula-based model. Moreover, a Monte Carlo-based algorithm is designed to quantify the sampling uncertainty associated with univariate and bivariate hydrological risk analyses. Two catchments located on the Loess plateau are selected as study regions: the upper catchments of the Xianyang and Huaxian stations (denoted as UCX and UCH, respectively). The univariate and bivariate return periods, risk and reliability in the context of uncertainty for the purposes of flood control and sediment transport are assessed for the study regions. The results indicate that sedimentation triggers higher risks of damaging the safety of local flood control systems compared with the event that AMF exceeds the design flood of downstream hydraulic structures in the UCX and UCH. Moreover, there is considerable sampling uncertainty affecting the univariate and bivariate hydrologic risk evaluation, which greatly challenges measures of future flood mitigation. In addition, results also confirm that the developed framework can estimate conditional probabilities associated with different flood events under various extreme precipitation scenarios aiming for flood control and sediment transport. The proposed hydrological risk framework offers a promising technical reference for flood risk analysis in sandy regions worldwide. [ABSTRACT FROM AUTHOR]

Under the background of changing global environment and frequent anthropogenic activities, rainfall-runoff relationship has suffered tremendous change in many regions of China, particularly in arid and semi-arid regions. The Jinghe River basin (JRB) in the middle of the Loess Plateau, which is the major base of grain production in Shannxi Province, has experienced significant changes in hydro-climatic variables and the relationship between them during the past decades, causing many water resources problems. In this paper, we focused on analyzing the variation characteristics of rainfall-runoff relationship in JRB, and quantitatively assessing the effects of climate changes and human activities on the runoff reduction. It was of great importance for mastering the evolution of hydrological cycle, water resources planning and management, and water and soil conservation in JRB. The monthly rainfall and runoff data were used in the study and summed annually to investigate the variation characteristics in 1960-2010. To detect the change points of rainfall-runoff relationship, the sliding partial correlation coefficients method was proposed and the change points were further confirmed by the double mass curve method. On the basis of the studies, the relative changes of rainfall, runoff, and rainfall-runoff relationship were analyzed around the change points. Moreover, we also introduced the Archimedean Copula function, from the perspective of probability, to analyze the probability of synchronous-asynchronous encounter of rainfall and runoff in JRB. What caused the variation of rainfall-runoff relationship? Climate change or human activities? To figure out this, the method of slope change ratio of cumulative quantity (SCRCQ) was adopted in this paper. According to these results, we obtained the following conclusions: (i) Annual runoff and rainfall presented wavelike decrease change. Nevertheless, annual runoff declined more greatly than rainfall; especially, in some periods annual rainfall increased, however, runoff decreased. This illustrated that some non-rainfall factors caused the occurrence of phenomenon in JRB; (ii) Change points of rainfall-runoff relationship occurred in 1996 validated by the sliding partial correlation coefficients method and double mass curve method. Meanwhile, we could ascertain the conclusion by the evidence of the process of human activities in JRB, which presented the increasing industrial, agricultural and domestic water consumption and large-scale water conservancy and soil conservation projects since 1990s; (iii) To compare the magnitude of the changes of rainfall, runoff and rainfall-runoff relationship, the hydrological variables series were divided into the periods of 1960-1996 and 1997-2010. Compared to runoff and rainfall in 1960-1996, the annual mean runoff and rainfall in 1997-2010 dropped 43.47% and 6.64%, respectively. The change of monthly rainfall had no significance in different periods. On the contrary, monthly runoff decreased more greatly and the difference was smaller in each month i.e. the runoff distribution for each month was more uniform. The correlation between rainfall and runoff diminished and runoff yield decreased under the same rainfall. When precipitation was above 400 mm, the relative change rate of runoff was above 40% in 1997-2010 compared to that in 1960-1996; (iv) The joint distributions of rainfall and runoff constructed by the Archimedean Copula function were different in 1960-1996 and 1997-2010, and the distributions in the 2 periods were fitting Clayton and Gumbel-Hougaard Copula better, respectively. The probabilities of synchronous-asynchronous encounter of the same rainfall and runoff changed strikingly in different periods. For instance, when rainfall was less than 550 mm and runoff was less than 40 mm, the probability of synchronous-asynchronous encounter was 44% in 1960-1996 and 73% in 1997-2010; (v) In JRB, human activities, i.e. non-rainfall factors, have played a fundamental role in rainfall-runoff relationship change. Further compared with some research results, the irrigation, the construction of reservoirs and the water-and-soil conservation measures in the region should be responsible for the change to a large extent. Compared to the period of 1960-1996, the contribution from human activities in the period of 1997-2010 reached about 81% and climate change was merely around 19% obtained by the method of SCRCQ. The research results can provide theoretical basis for water resource management and water and soil conservation for the administrators. [ABSTRACT FROM AUTHOR]

Thermal treatment and pyrolysis of vacuum residue/fraction oil blends have been conducted to quantitatively study the effect of the fraction oils recycle (i.e. the composition and the ratio of recycled fraction oils) on the stability of blends. The thermal treatment was completed in a static autoclave and the pyrolysis was run at 500 °C according to a standard test (i.e. the MCR test, ASTM D4530 ). The pyrolysis coupled with the polarized light microscopic observation of the coke products provided a quantitative and convenient method for predictive assessment of the stability of a given feed. It was strongly suggested that atmospheric gas oil distillate (AGO) was not conducive to the stability of blends. The recycle ratio of AGO and light vacuum gas oil distillate (LVGO) had better be confined to around 0.1 and the valid upper limitation of recycle ratio for heavy vacuum gas oil distillate (HVGO) could be increased up to 0.6 for the purpose of digesting ill-processable vacuum gas oil fraction (VGO). It was concluded that appropriate selection of recycled fraction and ratio might not only favor the improvement of coking products distribution and the process capacity debottleneck, but also be beneficial for maintaining the stability of coking feedstock, suppressing asphaltenes-involved phase separation in the exchanger sections at high temperature, and consequentially favor the operation period extending of coking plants. [ABSTRACT FROM AUTHOR]

Abstract: A systematic study was undertaken to reveal shot‐coke formation pathway and to find solutions to minimize and even eliminate shot‐coke formation during heavy oil delayed coking. The heavy oil used as coking feedstock was in the form of vacuum residue. Shot-coke-forming propensity was characterized by dynamic monitoring optical texture in the coke product, and coke morphology was macroscopically recorded by photography. Results show that the pathway for shot‐coke formation is distinctively stepwise: Feedstock→Formation of anisotropic spherules→Limited growth of the spherules in the viscous coking system→Mosaic optical texture in the solidifying bulk coke→Formation of primary shot coke→Formation of secondary shot coke. Coking feedstocks with higher asphaltene content, higher carbon residues, and higher heteroatom content have higher propensity to form shot coke. Particularly, when a coking feedstock has an asphaltene/Conradson carbon residue mass ratio greater than 0.5, H/C molar ratio less than 1.5, and colloidal stability parameter less than 3.5, it could be tentatively called shot-coke-forming feedstock, which shows dominant mosaic optical texture in the coke derived from typical delayed coking conditions. Hydrogen donating additives such as suitable FCC slurry (raw, i.e. without HDA/HDS treatment) are economically advantageous in reducing shot-coke-forming propensity. Feedstock blending, decreasing coking temperature, increasing coking pressure, increasing recycle ratio, and employing hydrogen donating additives are potentially effective measures for controlling shot‐coke formation. [Copyright &y& Elsevier]

Abstract: Simulated delayed coking characteristics of five petroleum residues from various sources in China and four fractions from one of the residues were investigated by thermogravimetry (TG), and interactions among the fractions were thus revealed. Results showed that properties of these petroleum residues and fractions varied over a broad range. The coke yields from residues were closely related to their carbon residues and those from the fractions varied much. Apparent thermal-cracking activity was in the order saturates>aromatics>resins>asphaltenes, while actual overall cracking intensity appeared in reverse order when measured by the heat effect derived from differential thermal analysis (DTA). The apparent cracking reactions of the fractions and their parent residue could be described in first order kinetics in two coking temperature zones with activation energies being 75–120 kJ mol− 1 and 130–210 kJ mol− 1. Saturates promoted coke formation from other fractions, while aromatics inhibited coke formation from both resins and asphaltenes; the coke yield from a residue was smaller than that by physical summation based on residue''s compositional fractions. It is thus possible to inhibit coke formation and enhance liquid distillate production by delayed coking of certain mixed petroleum residues. [Copyright &y& Elsevier]

• Sequential pretreatments were developed for the high-value utilization of slurry oil. • Comprehensive properties of feedstock were improved for the need of carbon materials. • Carbon materials, possessing better performance for application, were synthesized. FCC slurry oil (SO) is an important and yield-rich by-product of the FCC process, which can be regarded as the raw material of high-value-added carbonaceous products due to its abundant concentration of aromatic components, but essential pretreatments and purifications for SO are required before carbonization to eliminate the adverse factors. Appropriate sequential pretreatments aimed at achieving the high-value utilization of SO have been developed, and two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GC × GC-TOFMS), Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (1H NMR, 13C NMR) were implemented for the systematical properties analyses of SO and its derivatives after sequential pretreatments. Polarized-light microscope, scanning electron microscope (SEM) and X-ray diffraction (XRD) were used to evaluate the microstructures and microcrystal parameters of intermediate species and final products during carbonization. Through the varying degrees of sequential pretreatments, the comprehensive properties of feedstocks were improved gradually which further led to the diverse development of carbonaceous mesophase at the early stage of carbonization. Furthermore, ordinary or superior needle coke can be synthesized from the obtained oil samples during sequential pretreatments. The synthesized needle coke had suitable performance for the application in anode material of lithium-ion batteries. [ABSTRACT FROM AUTHOR]

• SO was utilized to produce MCMBs instead of being burned as carbonaceous fuel oil. • D-SO-MCMBs showed obvious coalescence while SBHD-SO-MCMBs have no coalescence. • The olefins produced during thermal reaction may promote the coalescence of MCMBs. • Fewer olefins and more naphthenes in SBHD-SO were facilitated to MCMBs preparation. • SBHD-SO-MCMBs best meet the requirement of the lithium-ion battery anode material. Slurry oil (SO) as the starting feedstock for the preparation of mesocarbon microbeads (MCMBs), an excellent carbonaceous anode material, is of significant commercial value and environmentally friendly. In this study, the MCMBs were prepared by thermal polymerization of SO after modification through suspended-bed hydrofining followed by distillation (SBHD). The results showed that SBHD is fully competent in saturating olefins and increasing naphthenes of SO simultaneously and thus bringing forth more naphthenic hydrocarbons and less olefins in SBHD-SO, which is indeed beneficial to the preparation of MCMBs with better morphology and more uniform size distribution. More interestingly, there was evident coalescence between MCMBs prepared from D-SO during the growth process due to the existence of abundant active groups on the MCMBs' surfaces, whereas the MCMBs prepared from SBHD-SO grew via absorbing the mesogen molecules in the mother liquor and there was no obvious coalescence between mesophase spheres. Moreover, the anode performance showed that the MCMBs prepared from SBHD-SO can deliver the highest discharge specific capacity of 315 mAh/g at a current density of 500 mA/g and an excellent stability of cycle performance. Thereby, the MCMBs prepared from SBHD-SO best meet the application requirements. This study paves a new strategy for the efficient preparation of MCMBs by using SO, which may expand the application prospect of SO. [ABSTRACT FROM AUTHOR]

• A Bayesian information-theoretic approach for disclosing design flood uncertainty. • How the parameter uncertainty is propagated to bivariate design flood is uncovered. • Uncertainty in design flood is enormous and increases along with return period. • Parameters of marginal distributions contribute most to design flood uncertainty. Copula-based statistical model has been extensively used to characterize the joint probability behaviors of extreme hydro-climatic design events, such as bivariate design floods. However, parameter uncertainty, not desirably but inevitably, accompanies the copula-based design flood estimation (CDFE) model which makes the inference results of design flood ambiguous. In this paper, we develop a Bayesian information-theoretic (BIT) approach to disclose design flood uncertainty arising from parameter uncertainty in CDFE model and furthermore examine how the parameter uncertainty is propagated to design flood estimation. Two catchments located in the Yellow River Basin, China, are selected as study regions. The research we have done indicates that design flood uncertainty is considerably large under parameter uncertainty. Worse still, the uncertainty in design flood increases along with the return period, thus making the design flood inference more ambiguous. Specifically, shape and scale parameters of marginal distributions have the largest contribution to the design flood uncertainty, followed by copula parameter, finally the location parameter of marginal distribution. Furthermore, the interaction between some parameters has dominant effect on design flood uncertainty compared with the individual effect of these parameters. These findings will enable better understanding the design flood uncertainty under parameter uncertainty. Moreover, the proposed BIT approach also offers a promising technical reference for design estimation of other types of extreme hydrological events, not limited to the design flood. [ABSTRACT FROM AUTHOR]

Olefin as one of the most important product molecules of FCC process drastically affects DO's thermal stability and the preparation of mesophase pitch due to its high reactivity. Several selected olefins have been added to hydrotreated DO for mesophase pitch preparation, crystal structures of their products had different degrees of damage and all of them were extremely uneven for size distribution. • Effects of olefins on mesophase pitch preparation were studied for the first time. • Crystal structure of mesophase pitch had been damage due to the addition of olefin. • Conjugated olefin had a much stronger effect on the development of mesophase pitch. Olefin as one of the most important product molecules of fluidized catalytic cracking (FCC) process is widely distributed in FCC decant oil (DO), and drastically affects DO's thermal stability and the preparation of mesophase pitch due to its high reactivity. Mild hydrogenation was performed on a low-sulfur DO to stabilize the unstable molecules, i.e., olefins. Several selected olefins (including monoolefinic and conjugated) were added to the hydrotreated DO to investigate their effects on thermal stability and mesophase pitch preparation. Bromine number, diene value, proton magnetic resonance (1H NMR), Fourier transform infrared spectroscopy (FTIR) and two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GC × GC-TOFMS) were used to characterize DO before and after hydrotreatment, and X-ray diffraction (XRD) and polarized optical microscope were used to detect the structure of mesophase pitch. Thermal stability of raw material was significantly enhanced through hydrotreatment where macromolecular aromatic hydrocarbons underwent partial hydrogenation, without over-hydrogenation. Influence of 1-octene, styrene and trans-stilbene on thermal stability of oil samples was enhanced successively due to the electron delocalization of conjugated olefins, and the effect of the amount of olefins added were significant. Olefins added to hydrotreated DO had different degrees of degradation on the crystal structures of mesophase pitch, and conjugated olefins had a much stronger effect on the development of mesophase pitch where the domain structures appeared in advance, with coarse-grained mosaic structure also interspersed in them. [ABSTRACT FROM AUTHOR]

Slurry-bed hydrotreating coupled with distillation may optimize the compositions and properties of heavy oils, including improving their hydrogen-donating ability of heavy oils. The effects of slurry-bed hydrotreating coupled with distillation on the compositions and properties of FCC slurry oil were determined by various analytical methods. 1H NMR was used to characterize and determine the hydrogen-donating ability of FCC slurry oil, and the structure of mesophase pitches formed by carbonization of FCC slurry oil were characterized by polarizing microscope, softening point and X-ray diffraction method. The results showed that slurry-bed hydrotreating obviously prevents FCC slurry oil from coking behavior during the distillation process, and overall compositions and properties of FCC slurry oil after optimization meet the requirements for producing mesophase pitch. Most importantly, the hydrogen-donating ability of FCC slurry was drastically increased from 0.392 (mg-H/g-Oil) to 1.917 (mg-H/g-Oil). In turn, in contrast with the raw FCC slurry oil, the slurry oil after the slurry-bed hydrotreating coupled with distillation easily formed mesophase pitch with a large flow domain structure, low softening point, and ordered microcrystal structure through carbonization. Thus, the purpose of preparing high-quality mesophase pitch was achieved. [ABSTRACT FROM AUTHOR]

• The probability of large-scale extreme drought was higher in forest ecosystems. • Compared to natural ecosystems, soil drought was more likely to occur in farmland ecosystems during winter. • The interaction between environmental factors in farmland ecosystems was stronger than that in natural ecosystems. • The dominant factor of soil drought in farmland ecosystems was temperature, and that in forest and grassland ecosystems was vegetation. Soil drought exhibits diverse characteristics across ecosystems due to intricate interactions within the soil–plant-atmosphere continuum. However, the dynamic variability and dominant factors of soil drought in different ecosystems remain unclear. To address this knowledge gap, this study characterized soil drought according to the standardized soil moisture index (SSMI) constructed using root-soil moisture data of the Global Land Data Assimilation System. Environmental factors were classified into three categories, namely climate factors (precipitation, temperature, and potential evapotranspiration), vegetation factors (NDVI and LAI), and topographic and soil factors (elevation, slope, aspect, groundwater storage, and soil texture). On this basis, the impact of terrestrial and meteorological multi-factors and their interactive effects on soil drought variation were examined through correlation analysis. Moreover, redundancy analysis (RDA) was employed to quantify the contribution of multiple drivers to soil drought in ecosystems, as well as identify the dominant factor. The results indicated that: (i) large-scale extreme drought events are more likely to occur in forest ecosystems than in farmland and grassland ecosystems; (ii) the duration of soil drought was longer in winter, especially in forest ecosystems; (iii) in winter, soil drought is more likely to occur in farmland ecosystems than in natural ecosystems; (iv) in farmland, grassland, and forest ecosystems, environmental factors explained 71.9%, 74.0%, and 77.8% of the changes in soil drought, respectively; (v) the dominant factor controlling soil drought was temperature for farmland ecosystems (F =321.20, p <0.01), and vegetation for forest (F =212.36, p <0.01) and grassland ecosystems (F =168.00, p <0.01). [ABSTRACT FROM AUTHOR]

• A new index was constructed based on ecological water shortage, considering climate, soil, and vegetation from ecosystem perspectives. • Climatic regions are classified based on the ecological geography, dry and wet conditions, and topographic characteristics. • Reveal the characteristics of ecological drought in different climate regions. • Identify the risk pattern of simultaneous ecological drought in the whole basin. The increase in the frequency and intensity of drought has caused serious changes and threats to the ecosystem. There is an urgent need to improve the characterization performance of the ecological drought index to better monitor the ecological drought. Thus, this study constructed a new ecological drought index, the standardized ecological water shortage index (SEWSI). The definition of SEWSI was based on the difference between ecological water requirement and consumption. Utilizing vegetation water requirement models to comprehensively consider environmental conditions, such as climate, soil, and vegetation. And, the twi-difference algorithm method was used to divide the crop planting system. The spatio-temporal evolution characteristics of drought, including drought frequency, drought intensity, drought duration, and affected area in three climatic regions (plateau mountain climate region, north subtropical humid region central subtropical humid region) in the Yangtze River Basin (YRB), were analyzed by the run theory method. Besides, the EOF model was used to determine the spatio-temporal distribution of ecological drought. The results showed that the ecological drought in the YRB presents a catabatic trend. An average of 31 ecological drought events occurred, and the average duration of the drought was about 3.18 months from 1980 to 2020. The frequency of light drought was more than 15 %, accounting for 55.82 % of climate region I. About 26.11 % and 26.91 % of climate region II and climate region III, where the frequency of severe drought was more than 5 %. The average duration of ecological drought in climate region I was the longest and the average drought intensity was the largest. The first four modes of EOF can explain 73.20 % of the temporal and spatial changes of ecological drought. Although various climatic regions generally exhibit a trend of humidification, there is also a trend of drought in some regions, such as drylands in Climate II, and Sichuan and Chongqing regions in Climate III. [ABSTRACT FROM AUTHOR]

Interbasin water transfer (IBWT) projects are of great practical significance for alleviating water shortages due to the nonuniform spatiotemporal distribution of water resources. An appropriate multisource IBWT management model can facilitate decision making for effective conjunctive use of the transferred and local water resources. This study proposes a hierarchical-planning model (HPM) that includes three core modules—water diversion, supply, and allocation modules—that are sequentially incorporated and clearly reflect the hierarchical relation among the diversion-supply-allocation system in the context of a multisource IBWT. The HPM is decomposed under two-stage programming and resolved with a coordinated particle swarm algorithm. Its effectiveness was examined by applying it to the Han-to-Wei IBWT project in China. The results indicate that the conjunctive operation rules with the expression of water transfer and supply rule curves fully exploit the hydrological heterogeneity and mutual complementarity. Further, the proposed model achieves a trade-off of the multiple sources and successfully meets the joint demands of different sectors and regions. Specifically, the mirror image phenomenon that arises during the process of the conjunctive operation, especially in continuously dry periods, highlights the noticeable mutual effect of the transferred and local water to cover the gap between that and the joint demands. The proposed model is a promising tool for integrated diversion-supply-allocation management of a multisource IBWT system, and it can be expanded to other water resource management systems involving the whole or partial process of water transfer, water supply, and water allocation. [ABSTRACT FROM AUTHOR]

Power system flexibility refers to the ability to respond to changing net loads within a predefined timeframe. The main causes of flexible demand are resource and load uncertainties. The joint interaction of resource and load uncertainty makes flexible demand more complex. Accurately assessing the power system flexibility and promoting flexible supply are important for maintaining grid safety and stability. In this study, a joint probability distribution for intermittent renewable energy sources (IRES) output and load forecast deviation is proposed. Subsequently, an optimal dispatch model that considers flexible demand and hydropower flexible supply is built to improve the operation scheme of flexible resources. A hydropower dispatch model that does not consider the probability of IRES output and load forecast deviation is used as the contrast model. A comparison of the results shows that the optimal dispatch model is more beneficial for maintaining grid safety and stability. The results show that the maximum upward adjustment flexible (UAF) margin of the optimal dispatch model of the Yalong River Downstream is 376 MW, whereas the maximum downward adjustment flexible (DAF) margin is 197 MW. This implies that a greater UAF supply is required in the case study to satisfy the power system flexible demand. • A quantitative method for power system flexibility is proposed. • A joint probability distribution considering resource and load uncertainties is presented. • An optimal dispatch model considering flexible margins is proposed. [ABSTRACT FROM AUTHOR]

A new heterogeneous K2CO3 supported by a layered double hydroxide (LDH), Mg–Al hydrotalcite, was prepared and used as a catalyst for the biodiesel preparation by a tri‐component coupling transesterification of methanol, vegetable oil, and methyl acetate. K2CO3/Mg‐Al exhibits high catalytic activities, and biodiesel yield can reach 99.48% within 20 min under 60°C, with 6 wt.% of K2CO3/Mg‐Al, 1:1:12 molar ratio of rapeseed oil, methyl acetate, and methanol. Fourier‐transform infrared spectroscopy, X‐ray diffraction (XRD), scanning electron microscopy, nitrogen physical adsorption, thermogravimetry analysis, and CO2‐chemical adsorption were used to assess the physical properties of the prepared K2CO3/Mg‐Al. Using the tri‐component coupling transesterification, 12.2% cost reduce can be get by reducing the cost from 8458 to 7424 ¥/t compared with di‐component transesterification containing oil and methanol as resource. [ABSTRACT FROM AUTHOR]

Hydrological modeling has provided key insights into the mechanisms of model state, such as the watershed partitioning level and optimization algorithm, and their impacts on the hydrological process, but the uncertainty of this impact is poorly understood. To this end, in this study, the effects of the watershed partitioning level and optimization algorithm for hydrological simulation uncertainty were assessed based on the semi-distributed TOPMODEL model, i.e., six watershed partitioning levels and three intelligent global optimization algorithms were used in the source region of the Yellow River. Meanwhile, the uncertainty contribution of the individual and interaction of the watershed partitioning levels and optimization algorithms on the hydrological process were dynamically evaluated using the variance decomposition method based on subsampling. Results showed that the impacts of the watershed partitioning level and optimization algorithm on the runoff simulation were particularly obvious for different characteristic periods. In the flood period, the optimization algorithm was the dominant factor affecting the runoff simulation uncertainty, with the proportion of up to 0.50, whereas the contribution of the watershed partitioning level was only 0.22. In the non-flood period, they contributed substantially to the uncertainty of the runoff simulation, accounting for about 0.30. Moreover, the interactions between the watershed partitioning level and optimization algorithm had a strong influence throughout the year, especially in the non-flood period, which may be because the hydrological model amplifies the output error and increases the interaction effect. Generally, the results shed important insight into reducing the uncertainty of the runoff simulation in future research. [ABSTRACT FROM AUTHOR]

Faced with increasingly severe energy and environmental issues, the clean and efficient utilization of coal slime is an urgent problem to be solved. Due to the concerns about carbon reduction and the intention to produce high quality gaseous products, pyrolysis experiments of coal slime coupled with in-situ and ex-situ CO 2 capture were carried out in a fixed-bed reactor. The effect of pyrolysis temperatures, mixing ratios of coal slime and CaO, and the CO 2 capture ways were investigated. The gaseous products from coal slime pyrolysis mainly included H 2 , CO, CO 2 , CH 4 , etc. It was revealed that after adding CaO, the hydrogen content in the pyrolysis gas increased significantly, while the CO 2 content decreased. When the temperature increased from 600 to 800 °C, the generation of gas products was enhanced. Due to the different interactions between the coal slime and CaO, the CO 2 capture efficiency of in-situ capture was higher than that of ex-situ capture, but ex-situ capture presented a relatively higher hydrogen production. When the coal slime/CaO mixing ratio is 1:1 and the pyrolysis temperature is 600 °C, the in-situ CO 2 capture ratio could reach 92.1%, and H 2 content at this situation is 56.5%. For ex-situ CO 2 capture, the capture efficiency of CO 2 increased with the increasing proportion of CaO. When the coal slime/CaO mixing ratio was 1:1, the ex-situ capture efficiency of CaO for CO 2 is 74% at 600 °C while the H 2 content is 59.3%. After CO 2 was captured by CaO, the diffraction peaks of CaCO 3 appeared in XRD patterns, and the microscopic morphology of CaCO 3 particles was clustered. Peaks corresponding to CaCO 3 also appeared in the C 1s, Ca 2p, and O 1s regions of the XPS peak spectrum, and showed a trend of first increasing and then decreasing as the temperature gradually increased. This study will provide a theoretical guidance on the efficient and clean utilization of coal slime. • CaO is used for the capture of CO 2 produced during coal slime pyrolysis. • Integration of CO 2 capture into coal slime pyrolysis could promote CO-H 2 production. • In-situ capture mode seems to have better CO 2 removal ratios than ex-situ capture mode. • In-situ CO 2 capture ratio could reach 92.1% when coal slime/CaO ratio is 1:1 at 600 °C. [ABSTRACT FROM AUTHOR]

Coking technological improvements are required to effectively upgrade/refine extra-heavy oil residues. The influence of types and blending ratios of coker-derived liquids on the coking performance of Venezuelan residue was studied in terms of product distribution and coke morphology. Blending of the coker diesel distillates (200-350 °C) with the residues was not suggested, given the negative interactions at all blending ratios (0-0.6) as concluded from coke yield analysis. Blending of the coker gas oil improved the coke quality and inhibited the coke formation. The recycle of heavy coker gas oil (430 °C+) at a blending ratio of 0.3 was most favorable. [ABSTRACT FROM AUTHOR]

The specific surface area and pore structure of carbon materials significantly impact their electrochemical performance. However, carbon materials with a uniform pore structure of micropores, mesopores, and macropores exhibit better capacitance performances. In this study, waste polyurethane was used as the carbon precursor. The polyurethane-based hierarchical porous (micropores–mesopores–macropores) carbon material was prepared by MgO template co-carbonization and KOH activation. The specific surface area and pore structure of the hierarchical porous carbon were optimized by changing the amount of magnesium acetate template and the activation temperature of KOH. The structure and composition of hierarchical porous carbon materials were characterized, and their supercapacitor performance was also tested. The results show that the hierarchical porous carbon material (PUHPC-700) has a uniform pore size distribution. Moreover, PUHPC-700 exhibited excellent supercapacitor performance, and its specific capacitance can reach 310 F g−1 (0.5 A g−1). This work provides a strategy to solve the complex problem of waste polyurethane by applying it to the production of supercapacitors, which play a dual role in environmental protection. [ABSTRACT FROM AUTHOR]

Excessive amounts of fluoride in water cause irreversible harm to people and seriously threaten human health. Therefore, fluoride ion in water should be deeply removed. The waste liquor of itaconic acid fermentation contains many organic acids, residual sugars, proteins, and other impurities, which are difficult to remove. Thus, in this study, the itaconic acid fermentation waste liquid was successfully mixed with urea to prepare N-doped porous carbon (PC-N). The prepared PC-N was applied for the removal of fluoride in water. The specific surface area of PC-N is as high as 1803 m2 g−1, and the SEM results show an abundant pore structure. The FTIR results showed that the adsorbent surface had an abundant functional group structure. The removal rate of F− by PC-N was 91% when pH = 6. After 6 cycles of recycling, PC-N performance remains stable at about 73% of that of the fresh adsorbent. Moreover, Freundlich and PSO can better fit the adsorption data, indicating that F− on PC-N adsorption results from the joint action of physical and chemical adsorption. After calculating the adsorption thermodynamics, ΔH and ΔS are −14.5529 kJ mol−1 and 13.6507 J (mol K)−1, and ΔG is negative, indicating that the adsorption process is exothermic and spontaneous. The outcome results of this work have achieved the goal of "treating waste with waste" and realized the dual protection of the environment. [ABSTRACT FROM AUTHOR]

The load distribution of cascade hydropower stations is associated with the safe operation of the hydropower stations and power grids. The conventional load distribution of cascade hydropower stations does not consider the synchronous operation of the water level. The inconsistent water level variation process of cascade hydropower stations is not conducive to the safe operation of hydropower stations and power grids. Therefore, the main purpose of this paper is to introduce the concept of equal reservoir full storage rate (ERFSR) to guide the load distribution of cascade hydropower stations. In addition, hydropower is used for new energy consumption considering the advantages of the rapid start-stop in hydropower units. The load distribution model of cascade hydropower stations is established, and three cases are set to verify the universality of the proposed model in the upper reaches of the Yellow River. The results show that (1) The concept of ERFSR can effectively guide load distribution and realize water level synchronization of cascade hydropower stations. (2) The output process of each hydropower station can be basically consistent with the load process to achieve synchronous peak shaving. (3) New energy consumption has little effect on the daily water consumption of downstream cascade hydropower stations. [ABSTRACT FROM AUTHOR]

[Display omitted] • A trash to high-value-added material strategy of waste conversion is presented. • Two interactions of polyurethane surface and silica are revealed. • The mechanism of coalescence demulsification of emulsions is revealed. • The obtained materials can separate immiscible and emulsified oil/water mixtures. • The scaling up of the oil/water separator from lab to a factor of 100 was studied. Polyurethane plastic waste (PUPW), a port-abundant solid waste, is difficult to degrade naturally and poses a severe threat to the environment. Hence, the effective recycling of PUPW remains a challenge. Herein, a strategy of converting PUPW into stacked oil/water filtration layer grain through a layer-by-layer (LBL) assembly process is investigated. Notably, such PU-based, grain-stacked, and switchable wettability of the oil/water filter layer is first reported. The grain-stacked filter layers are flexible for separating immiscible oil/water mixtures, water-in-oil emulsions (WOE), and oil-in-water emulsions (OWE) under gravity over 10 cycle-usages. They can withstand strong acid/alkali solutions (pH = 1–14) and salt solutions over 12 h. Besides, 100-times scale-up experiments have indicated that the obtained filter layers exhibit an upper to 98.2 % separation efficiency for 10 L real industrial oil/water emulsion in the 24 h continuous operation. The demulsification mechanism for emulsions is that the electrostatic interaction along with adsorption between emulsion droplets and grains leads to the uneven distribution of surfactants on the interface film of the emulsion droplets, increasing the probability of tiny droplets colliding and coalescing into large droplets to achieve oil/water separation. This work proposes an effective and economical method of abundant plastic waste for industrial-scale oil–water separation rather than just on the laboratory-scale. [ABSTRACT FROM AUTHOR]

Thesolubility of hydrogen in Venezuelan heavy coking gas oil (HCGO),Karamay atmospheric residue (KRAR), Liaohe atmospheric residue (LHAR),and Venezuelan atmospheric residue (VNAR) was measured at temperaturesin the range 150 °C to 350 °C at pressures up to 11 MPaby a modified direct method. The measurement accuracy and reliabilitywere examined by determining hydrogen solubility in toluene and n-heptane at temperatures of 25 °C, 50 °C and100 °C, and results are in a good agreement with the data reported.The order of hydrogen solubility in the four feedstocks at the sameexperimental condition is VNAR < LHAR < KRAR < HCGO. Theimpact of oil properties, such as aromatic ring number and alkyl chainlength, on hydrogen solubility was discussed. The results indicatethat the condensed aromatics play a key role in the fractions of highboiling points. The hydrogen dissolving capacity in different derivedoils with the same boiling range can be tentatively determined viaanalyzing the H/C atomic ratio of the oils. [ABSTRACT FROM AUTHOR]

Hydropower plays an extremely important role in the energy market with the increasing energy demand. The intra-annual runoff distribution (IARD) in the hydrological year has an important impact on the energy generation of cascade hydropower plants (CHP). This study evaluated the non-uniformity of IARD of the Datong River basin (DRB) in the hydrological year. The optimal operation model of CHP was constructed based on the genetic algorithm to investigate the impact of the non-uniformity of IARD on the energy generation of CHP. This study shows the following: 1) The observed runoff series has a decreasing trend, the non-uniformity of IARD has an increasing trend overall. 2) The energy generation of CHP shows a weak decreasing trend affected by the decrease of runoff and the increase of non-uniformity. 3) With or without water diversion, the CHP energy generation decreases with the increase of non-uniformity of IARD. 4) The difference of energy generation of CHP between consideration or not the water diversion is about 400 GWh when the inflow frequency is less than 50%. 5) The impact of non-uniformity of IARD on energy generation will be greater with the inflow increasing. This study can provide theoretical support for the water resources management and operation of CHP. • The non-uniformity of IARD was systematically evaluated. • Evaluating the impact of non-uniformity of IARD on energy generation of CHP. • Higher impact of non-uniformity of IARD on energy generation with greater inflow. • Strong correlation degree between the energy generation and the non-uniformity of IARD. • Water diversion causes about energy generation economic loss of 120 million CNY in the DRB. [ABSTRACT FROM AUTHOR]

The hydro-wind-PV-battery complementary operation has the potential to increase the integration of renewable energy sources into power grid. Nevertheless, the determination of the optimal capacity configuration mode and size for a hydro-wind-PV-battery complementary system (HWPBS) remains a persistent challenge. This study proposes a capacity planning framework for the HWPBS considering the characteristics of multi-energy integration to power grid. First, the centralized (CCP) and distributed (DCP) configuration patterns considering the ways of multi-energy integration into power grid are proposed to explore the optimal capacity configuration mode. Second, considering the randomness of incoming water of hydropower stations, a scenario analysis technique is proposed to obtain the typical inflow scenarios. Then, with the objectives of maximizing expected renewable generation and minimizing expected power abandonment and load loss, the capacity configuration models for the HWPBS under the CCP and DCP are developed. A load reconstruction method is proposed to reduce the computational burden. The parallelogram method is implemented to linearize the hydropower production model. Additionally, a set of indicators are proposed to evaluate the economy and reliability of the HWPBS. The proposed framework is applied to the Yalong River Basin. The results show that: the wind-PV configuration capacity is affected by load demand, battery storage and configuration patterns. The load demand process with better correlation to wind-PV output is advantageous for integrating wind and solar resources. Battery storage can effectively reduce power abandonment and load loss, and the configuration pattern has a significant impact on the final capacity of wind-PV power. The capacity configuration method of the hydro-wind-PV-battery complementary system. [Display omitted] • Considering the characteristics of multi-energy integration into power grid, the capacity configuration models for the HWPBS under the CCP and DCP are proposed. • The CCP is more favorable for the large-scale development of wind-PV power than the DCP. • The configuration sizes of the wind, PV, and battery storage in the Yalong river basin are determined. [ABSTRACT FROM AUTHOR]

• The effects of fairness and efficiency on water allocation are explored by constructing different of optimization models. • Welfare economics theory is introduced to balance the efficiency and fairness of water-resource regulations. • An integrated model of water-resource scheduling and allocation is constructed based on a proxy model, which significantly improves computational efficiency. Water is an important natural resource with economic and social attributes. The most important aspects of water resource regulations are fairness and efficiency. Achieving a balance between fairness and efficiency is a challenging but popular topic in related research. In this study, three optimal water-resource allocation models were constructed: efficiency priority (E-P), fairness priority (F-P), and stratified water supply (SWS). The three models were applied to the Yellow River Basin (YRB), and the results show that, compared with the E-P and F-P models, the SWS model is a more equilibrium model with significant advantages. Considering the impact of reservoirs on water allocation, an optimal operation model for cascade reservoirs groups, considering fairness and efficiency, was constructed based on the principle of welfare economics and coupled with the SWS model. Proxy modeling was used in the coupling process to enhance the computational efficiency of the integrated model. Compared with the SWS model, the integrated model can better satisfy the water supply demand outside a river while ensuring the ecological environment and sand flushing demand inside the river; its fairness and efficiency are also significantly improved. In addition, integrated models can effectively address hydrological uncertainty and reduce losses. The model proposed in this study has significant flexibility and application potential and can provide a reference for other governments and water-resource management institutions worldwide. [ABSTRACT FROM AUTHOR]

• A new form IBWT is proposed to cope with efficiency declines of typical IBWT. • Joint operation coordinating water supply, transfer and receipt rules are derived. • A three-step framework is developed to identify these DIBWT operations. • DIBWT can balance transfer-supply-demand while preserving ecological flow. As the efficiency of the long-running inter basin water transfer (IBWT) projects declines, the increasing water crisis in the intake area and the deteriorating ecosystem problems in the transferred area have gradually worsened. In this paper, a new form of IBWT, the dual-IBWT (DIBWT), is defined, in which the original transferred area (OTA) and additional transferred area (ATA) are integrated to transfer water resource from two basins to a corporate intake area (CIA). Unlike a typical IBWT, the OTA is one of the transferred areas for the CIA as well as the recipient area of the ATA and plays a dual role in this DIBWT system. A multi-objective DIBWT model involving interconnected OTA and ATA submodels is developed for fulfilling joint transfer targets, flattening water transfer fluctuations, and replenishing ecological flow demands. Then, a three-step framework is presented to derive the multi-resource joint operation rules coordinating the water-supply, water-transfer and water-receipt rules together. In particular, the simulation-optimization approach (SO) is applied to obtain the optimal solution based on a time series of 56 years. The Jialing across Han River to Wei River Water Transfer (JHW-DIBWT) project in western China is used as a case study to assess the performance of the DIBWT compared to a typical IBWT. The results indicate that the JHW-DIBWT has significant advantages in alleviating the conflicts of transfer-supply-demand and restoring the river ecosystem with the aid of additional water resources. Meanwhile, its superiority is revealed by the corresponding joint operation rules of the water-supply, the water-transfer and the water-receipt rule curves, which also can serve as a practical guide for multi-objective and multi-resource water system management. Therefore, the main focus of this paper is not limited to compare the performance between these two IBWTs, but more importantly, it provides a promising framework for extending the study of different form of IBWTs. [ABSTRACT FROM AUTHOR]

The effectiveness of continuous synthesis of petroleum coke-based potassium ion battery anodes by chemical activation agent cycle was systematically studied. The potassium ions storage performance in the synthesized carbon anode was measured. High‑sulfur petroleum coke, as a natural sulfur-doped hard carbon skeleton, can provide an excellent active site for the storage of potassium ions. Ultrasonic intensification significantly reduces the elution time required for neutralization and eliminates the need for a forced increase in elution temperature and rate to improve elution efficiency. In the continuous synthesis process, the recycled chemical activation agent not only does not destroy the activation effect but also has stable activation performance and a good driving force for the growth of activated carbon quality (the specific surface area is 1000 ∼ m 2 g− 1 ). Moreover, the sulfur content of the prepared hard carbon anode gradually decreases, whereas its electrical conductivity gradually increases, resulting in an increase in its potassium ions storage capacity. The carbon anode prepared by chemical activation agent after four cycles has a high reversible capacity of 290 mAh g− 1 at 0.5 A g− 1 and excellent cycling stability (99.5% hold rate at 0.5 A g− 1 after 400 cycles). The galvanostatic intermittent titration technique results show that appropriate sulfur content and perfect carbon skeleton structure can promote potassium ions intercalation kinetics. In conclusion, the chemical activation agent cycling strategy can be used to achieve the continuous synthesis of petroleum coke-based potassium ion battery anode. [Display omitted] • The ultrasonication assisted successive synthesis of HSPC-based AC was researched. • The different post-treatment cost of AC was found. • Serial analysis was used to elucidate ultrasonication enhancement mechanism. • The recycle of K 2 CO 3 registered a stable activation performance with growth of AC quality. [ABSTRACT FROM AUTHOR]

With uncertain wind and PV power integrated into the grid, the difficulty of peak shaving is exacerbated. Therefore, the peak shaving operation of hydropower has become one of the most important problems in power system. In this paper, an optimal operation strategy of hydro-unit level coordinated peak shaving and economic operation in hydro-wind-PV hybrid system under uncertain conditions of wind and PV power is proposed. Firstly, the uncertainty of wind and PV power is described based on Latin hypercube sampling and scenario reduction methods. Secondly, a two-layer optimization model considering wind and PV uncertainty is established. And then, the synchronous peak shaving strategy and the improved lambda flow iteration strategy are proposed to solve the model. A case study is performed with the HWPHS in the Yarlung Zangbo River basin of China. The results show that (1) The residual load of power system fluctuates steadily under the condition of wind and PV uncertainty, and the peak shaving rate is 95.53%. (2) Compared with the DP algorithm, the proposed algorithm can increase the economic efficiency by 0.89% when solving the lower-layer model. (3) The V3 shaped mapping function proved to be superior to other functions. [ABSTRACT FROM AUTHOR]

The factors leading to olefinic hydrogen signal shielding in the 1H NMR spectra of thermally cracked vacuum residue (VR) and its heavy fractions were revealed using a series of model compound systems, and the effect of olefinic hydrogen signal shielding on the determination of olefinic hydrogen content was elucidated. There were two main factors leading to the olefinic hydrogen signal shielding in the 1H NMR spectra of olefins in heavy fractions, i.e. intramolecular and intermolecular. For the olefin itself in heavy fractions, the chemical shift of the olefinic hydrogen closest to the aromatic ring was in the aromatic region rather than the olefinic region due to the π-π conjugation effect between the double bond and the intramolecular aromatic ring. Notably, the response intensity of the olefinic hydrogen signal could be weakened or even disappear due to the suppressive effect of the intermolecular aromatic structures in other polycyclic aromatic hydrocarbons (PAHs), while alkanes and monocyclic aromatics had little effect on the olefinic hydrogen signal response. Although the olefinic hydrogen signal was detected merely at about 5.30 ppm in the 1H NMR spectra of heavy fractions, these olefinic structures may be predominantly of the R─CH═CH 2 type rather than the R─CH═CH─R′ type. More importantly, the measured olefinic hydrogen content of thermally cracked VR and its heavy fractions may be considerably lower than the actual content, with the measured content being only about 30–40 % of the actual content. This is mainly due to the weakening and disappearance of the olefinic hydrogen signal, coupled with the fact that the integral area of the possible olefinic hydrogen signal in the aromatic region was overlooked when calculating the total integral area of the olefinic hydrogen signal in the 1H NMR spectrum. [Display omitted] • π-π conjugation led to chemical shift increase of olefin hydrogen in aro-olefin. • PAHs can cause olefin hydrogen signal to weaken or even disappear in 1H NMR test. • Measured olefin hydrogen content of Re/Asp was much lower than actual content. • Olefin structures in Re/Asp may be mainly of R─CH═CH 2 rather than R─CH═CH─R′. [ABSTRACT FROM AUTHOR]

[Display omitted] • PtPd/CN was fabricated for cyclohexane dehydrogenation at low temperatures. • Pt 0.75 Pd 0.25 /CN catalyst exhibited better catalytic activity than Pt/CN and Pd/CN. • The electronic coupling in PtPd alloy promotes catalytic performance. While Pt-based heterogeneous catalysts have been extensively studied for cyclohexane dehydrogenation, the reaction efficiency under low temperatures remains to be resolved. In this paper, ultrafine PtPd alloy nanoparticles homogeneously anchored on nitrogen-doped carbon were synthesized and applied for cyclohexane dehydrogenation. The experimental results indicate that the synergistic effect of Pt-Pd in PtPd/CN catalyst enhances the activity and durability of the catalyst in cyclohexane dehydrogenation compared with Pt/CN and Pd/CN catalysts. The as-prepared catalyst (labeled as Pt 0.75 Pd 0.25 /CN) exhibits an excellent catalytic performance with an initial TOF value of 90.07 mmol·g−1 metal ·min−1 and a 100% H 2 purity for cyclohexane dehydrogenation at 180 °C, exceeding reported values under comparable reaction conditions. Catalyst characterizations and DFT calculations reveal that the electronic coupling effect of Pd and Pt in PtPd/CN catalyst makes the d-band center of Pt active sites closer to the Fermi level, which promotes the specific adsorption/activation of cyclohexane on Pt active sites, thus improving the catalytic performance of cyclohexane dehydrogenation. Under this guidance, the synthesized PtRu/CN and PtIr/CN alloy catalysts exhibited similar enhanced activity in cyclohexane dehydrogenation. This work provides insights into the rational design of efficient and stable Pt-based bimetallic catalysts for cyclohexane dehydrogenation. [ABSTRACT FROM AUTHOR]

• The thermal reaction of residue and SARA fractions at 250–400 °C was studied. • Resins and asphaltenes produced coke at 250 °C with no coke induction period. • Asphaltenes are the sole fraction that generated reactive radicals at 250 °C. • Coking at high temperature is strongly correlated with the radical evolution. • Maltenes could suppress asphaltenes coking, serving as the immunity system. In this study, the coking propensity and reactive radical evolution of heavy residue and SARA fractions at 250–400 °C were studied to gain an insight into the coke induction process. The interactions among fractions for thermal coking were discussed. Results showed that residue started to form coke (i.e. toluene-insoluble at room temperature) at 350 °C for longer times while resins and asphaltenes have already extensively produced coke at 250 °C with no coke induction period. This indicates that the coke induction depends on the solubility gap of reactant and coke. The coking process can be fitted with the second-order and autocatalytic kinetics for residue while second-order kinetics for heavy fractions with initial coke precursor amount varying with temperature. Asphaltenes are the sole fraction that generated reactive radicals at 250 °C and responsible for the radicals of thermal residue. The explosion of reactive radicals began when the temperature exceeded 350 °C and became steady as the thermal reaction proceeded. The coke at low temperatures mainly originated from the molecules aggregation with faint radical emergence while that at high temperatures is strongly correlated with the radical evolution. The maltene subfractions could suppress the coking of asphaltenes possibly because of the physical solvation and chemical hydrogen donating behavior to cap reactive radicals. It can serve as the intrinsic immunity for coke inhibition of heavy residue during thermal partial upgrading. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The morphological characteristics of petroleum cokes differ apparently from each other. • FWHM of D 1350 is more appropriate than I D1350 / I G1580 for morphology criterion. • An explicitly Growth/Sigmoidal relationship between OTI and FWHM of D 1350 was observed. • RS could be a suitable and convenient method to quantitatively assess the morphology. Abstract A series of petroleum coke species obtained from commercial plants has been studied by polarized-light microscopy observation (PMO), scanning electron microscope (SEM), and Raman spectroscopy characterization (RS). The morphological characteristics of needle coke, shot coke, and transition coke differed apparently from each other. An explicitly close Growth/Sigmoidal relationship between parameters determined from polarized-light micrographs and Raman spectra was observed. The full width at half maxima (FWHM) of D 1350 was more appropriate than I D1350 / I G1580 for morphological correlation, and then establishing the criterion. It was shown that RS with proper spectra decomposition procedure could be a suitable and convenient method to quantitatively assess the morphology of petroleum cokes. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • SPs are composed of catalyst fragments and organic substances wrapped around them. • The outer surface of SEINS is sufficient in oxygen-containing sites. • A new structure of SPs has been proposed and verified. • The research offers a method to considerably improve clarifying efficiency. Abstract Suspended particles (SPs) were separated from an FCC Slurry Oil (SLO) via centrifugation with the aid of toluene-dilution. Further solvent extraction of SPs with CS 2 /toluene (50 V/V%) mixed solvent would generate solvent extraction insolubles (SEINS) and solubles (SES). They were sent for a series of chemical and structural characterizations, respectively, in the hope of providing clues to address issues from sedimentation and clarification processes. It was found that SPs were composed of catalyst fragments and organic substances wrapped around them, serving as a shield. The characterizations from TEM and XPS strongly suggested that the outer surface of SEINS was sufficient in oxygen-containing sites (organic functional groups and aluminosilicate), while the outer surface of SPs was not. High oxygen content and almost same nitrogen content of SES, comparable with that of asphaltenes, were detected through XPS characterization. This rationalized the strong adsorption of SES on SEINS in the form of a tedious solvent extraction process. A new structure of SPs has thus been described on the basis of these characterizations. Design sedimentation experiments verified the SPs' structure. Furthermore, the experiments offered a promising way for acquiring high clarification efficiency with rather low usage of sinking agent through solvent pretreatment. [ABSTRACT FROM AUTHOR]

MicroRNAs serve crucial functions in cancer progression by inhibiting the translation of target genes and causing mRNA degradation. However, the underlying regulatory mechanism of Let-7b in osteosarcoma (OS) has not, to the best of our knowledge, been comprehensively elucidated. The aim of the present study was to investigate the function of Let-7b in OS and clarify the regulation of insulin-like growth factor 1 receptor (IGF1R) by Let-7b. It was observed that Let-7b was significantly downregulated in OS tissues and cell lines compared with the matched adjacent non-tumorous tissues and human normal osteoblastic cell line hFOB 1.19. Overexpression of Let-7b significantly inhibited the proliferation and invasion of U2OS and SAOS-2 cells. A luciferase reporter assay validated that IGF1R was a downstream and functional target of Let-7b. Let-7b was also able to decrease the expression levels of IGF1R protein. Functional studies revealed that the antitumor effect of Let-7b was probably due to targeting and suppressing IGF1R expression. Furthermore, in OS tissues, IGF1R was identified to be significantly upregulated and negatively correlated with Let-7b levels. In conclusion, the results of the present study indicated that Let-7b suppresses OS cellular proliferation and invasion via targeting IGF1R. A novel candidate prognostic factor was identified and it is suggested that the Let-7b/IGF1R axis may represent a novel anti-metastasis therapeutic target in OS. [ABSTRACT FROM AUTHOR]

Hydrogen transfer property is of great importance in the carbonization of heavy oils. Thermal treatment under hydrogen was performed on a raw slurry oil (SO) from FCC process. The theoretical hydrogen-donating property of SO fractions before and after treatment was predicted by comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry. The hydrogen-transfer experiments using anthracene (ANT) and 9,10-dihydroanthracene (DHA) as chemical probes were carried out to determine the hydrogen transfer ability (HTA) of SO fractions, the effect of which was examined by subsequent carbonization experiments. Results show that the donatable hydrogen contents of SO fractions are increased after thermal treatment under hydrogen. A modified method for calculating the hydrogen-donating ability (HDA) of the fractions is proposed on the basis of the 1 H NMR data of the reacted mixtures derived from the hydrogen-donating experiments. The results calculated with this method are more accurate with inherent ANTs and DHAs considered. The HDA is found to be closely related to the composition of hydroaromatics in terms of the content and hydrogen-donating activity. The hydrogen-accepting ability (HAA) of the fractions is also calculated with similar method proposed accordingly, and thus the hydrogen-donating index that quantitatively describes the HTA is obtained. Thermal treatment under hydrogen improves the HTA of the fractions considering the increased HDA and decreased HAA after treatment, and also improves the morphology of derived semi-cokes as indicated by subsequent carbonization experiments. The correlation between the HTA of SO fractions and the morphology of derived semi-cokes reveals that the quality of derived cokes improves as the HTA of carbonization feedstocks improves, not necessarily in positive correlation with the HDA of SO fractions nor necessarily in negative correlation with the HAA of SO fractions. [ABSTRACT FROM AUTHOR]

Highlights • A method to evaluate the thermal stability of carbonization feedstocks is proposed. • Thermal treatment can improve the thermal stability of feedstocks. • Thermal stability of feedstocks is essential for the production of better cokes. Abstract Pretreatment of slurry oil (SO) from fluid catalytic cracking process is critical to its high value-added utilization in producing carbonaceous materials. In this study, the SO fractions before and after thermal treatment were characterized in terms of bulk property, composition, and thermal stability. A method using thermal excitation followed by spot test was proposed to evaluate the thermal stability of the fractions. The average structural information shows that the fractions after thermal treatment have shorter alkyl side chain length and are increased in aromaticity. The composition analysis reveals that the middle fraction is mainly composed of three to five-ring aromatics with short side chains, and that the content of four-ring aromatics decreases while the contents of three-ring as well as five-ring aromatics increase after thermal treatment. An increase in thermal stability of the middle fraction as well as the corresponding five narrow fractions is observed and is attributed to the conversion of reactive components in the middle fraction into residues. The carbonization experiments reveal that feedstocks with higher thermal stability tend to have better mesophase development performance. [ABSTRACT FROM AUTHOR]

In this study, catalyst particles (the main component is Al 2 O 3 –SiO 2 ) were removed from the fluid catalytic cracking slurry oil by adding a polyacrylamide flocculants (1200 μg/g) and a ammonium citrate aqueous solution weighting agent (10% by weight of the slurry oil) at 95 °C, and then settled for 18 h. The ash content which determined by the muffle stove was considered as a criteria for measuring the efficiency of sedimentation. The size and distribution of the catalyst particles, before and after sedimentation, were analyzed using a laser particle size analyzer and a light transmission microscope. The results showed that the removal efficiency could reach 95.12% when both the flocculants and weighting agent were added. However, either the flocculants or weighting agent applied individually could only obtain inferior removal efficiencies of 87.04% or 68.76%, respectively. It would be attributed to the synergistic effect between the two agents. Moreover, it was also found that the flocs were rapidly formed from original catalyst particles and the flocculants firstly. Then the weighting agent provided assistance for the sedimentation of the flocs, of which the process was identified as the control step. The sedimentation process established in the experiment might play a role in the industrial removal of catalyst particles from slurry oil in the future. [ABSTRACT FROM AUTHOR]

[Display omitted] • The olefin distributions of thermally cracked products derived from VR was investigated. • The effect of olefinic-bond-containing aromatics (OAH) on coke formation was revealed. • Evolution characteristics of OAH during thermal reaction was studied. • OAHs can form larger molecules via non-free radical reaction. The distributions of olefinic-bond-containing aromatic hydrocarbon (OAH) and the effect of OAH on coke formation during heavy oil thermal cracking have been rarely studied in the past. Here, the information of olefins in thermally cracked products derived from vacuum residue (VR) was investigated first, and then the effect of OAH on coke formation was elaborated by revealing the evolution characteristics of self/co-addition systems participated by representative OAH model compounds. The results found that OAHs were generated during VR thermal cracking, and they could participate in further reactions to promote coke formation. During thermal reaction, OAHs were more reactive for addition reactions than alkenes, and the reactivity of OAH increased roughly with the number of aromatic rings. Meanwhile, the higher concentration of OAH or the longer thermal reaction time or the higher thermal reaction temperature, the higher conversion of addition products, and the greater condensation degree of reaction products. OAHs participating in the larger structure molecule formation involves free radical addition reactions, which could occur between different OAHs as well as between OAHs and conventional aromatic molecules. More importantly, OAHs could form larger structure molecules by direct addition reaction of unsaturated double bond via non-free radical addition reaction, thus promoting fast coke formation. [ABSTRACT FROM AUTHOR]

[Display omitted] • V, Ni, and Fe in wastewater were decontaminated and crystallized into nanoparticles. • The formed V 2 O 3 , NiO, and Fe 3 O 4 could catalyze both WGSR and PAHs hydrogenation. • The WGSR was coupled into PAHs hydrogenation by providing in-situ H 2. • Metals in wastewater and PAHs in fuel could be reduced simultaneously. The developing chemical demetallization technologies of petroleum emit thousands of tons of V, Ni, and Fe into water bodies annually for just one oil refinery. For this reason, a metal-containing wastewater (MCW) treatment and reutilization technique is highly demanded to be integrated into petroleum processing. This work introduced an in-situ decontamination of V, Ni, and Fe-containing wastewater from oil refineries into catalytically active particles for polycyclic aromatic hydrocarbons (PAHs) disposal. The water–gas shift reaction (WGSR) was coupled into the reaction system by providing the in-situ H 2. In one step, 98.7 wt% of soluble metal ions were precipitated into metal oxides, and 89.6 wt% of anthracene was hydrogenated. It took only 1 h for V, Ni, and Fe ions to crystallize into nanoparticles of V 2 O 3 , NiO, and Fe 3 O 4 , which could promote both the PAHs hydrogenation and the WGSR. The hydrogenation efficiency via in-situ H 2 was 48.7 % higher than that via ex-situ H 2. With the increase of PAHs aromatic ring number, the PAHs hydrogenation via in-situ H 2 was enhanced. Therefore, this method could simultaneously effectuate the separation of heavy me tals from MCW and the disposal of noxious PAHs in fuel oils. [ABSTRACT FROM AUTHOR]

[Display omitted] • Effect of olefins on the coking propensity of residual oil (RO) was investigated. • The coking propensity of RO was higher than that of original VR. • The coking propensity linearly increased with the total olefin content of RO. • Olefinic-bond-containing Asp contributes the most to the increased coking propensity, followed by olefinic-bond-containing Re. Olefins, especially olefinic-bond-containing aromatics (OAH) may have a significant effect on the coking propensity of heavy residual oil (RO) derived from vacuum residue (VR) thermal cracking products in the further deep processing. However, this has been rarely studied in the past. In this work, the structure of RO (boiling point > 500 °C distillate) products and their SARA fractions derived from thermal cracking of VR under different conditions were systematically characterized by 1H nuclear magnetic resonance (1H NMR) and Fourier transform infrared (FT-IR) spectroscopy to investigate the occurrence pattern of olefins. The coking propensity of RO in the further processing was evaluated by thermal gravimetric (TG) and coking factor analysis, and the effect of different olefins on the coking propensity of RO in further processing was revealed. The results showed that the thermal cracking led to the occurrence of olefins, especially OAHs in resins (Re) and asphaltenes (Asp). The highest olefinic hydrogen contents of RO and its SARA fractions were detected at the thermal cracking condition of 415 °C for 40 min, which were 2.9 %, 4.0 %, 3.4 %, 2.8 %, and 2.4 %, respectively. Interestingly, RO obtained at the thermal cracking condition of 415 °C for 40 min also had the highest content of TG carbon residue (11.2 wt%) and the largest value of coking factor (5.33 %). Significantly, the TG carbon residue content and coking factor value of RO linearly increased with the total olefinic hydrogen content of RO, suggesting that the occurrence of olefins during thermal cracking significantly contributed to a greater coking propensity of RO in further deep processing. More importantly, an in-depth investigation by adding different olefin model compounds to the original VR thermal reaction system revealed that the olefinic-bond-containing aromatics in Asp may confer the greatest contribution to the increasing coking propensity of RO, followed by the olefinic-bond-containing aromatics in Re. [ABSTRACT FROM AUTHOR]

FCC decant oil was always used as the raw material for the preparation of high-value-added carbonaceous materials. There is little disagreement that the free radical mechanism induces thermal polymerization reactions between reactant molecules and intermediate species, which leads to the formation of carbonaceous mesophase in the early stage of carbonization. Olefinic hydrocarbons were recently found to be widely distributed in FCC decant oil in our previous research, and these chemically active compounds usually possess weak π-bonds in molecules and thus potentially form free radicals easily, which may impact the carbonization performance dramatically. This research investigated the effects of olefinic compounds on the preparation of needle coke from FCC decant oil, as well as the corresponding mechanism in depth combined with the evolution pattern of the intermediate species during liquid carbonization. ESR analyses were adopted to evaluate the variation of the concentration of stable free radicals. Stable free radical concentration varied greatly in diverse polymerizing systems along with the carbonization process. Olefin showed a significant effect on the stable free radical concentration during carbonization. The stable free radical concentration of the polymerizing system derived from FCC decant oil was 3.32 × 1020 spins/g when the reaction time was 4 h. But with 3 wt% addition of 2-vinylnaphthalene and squalene in FCC decant oil, the stable free radical concentration increased to 2.14 × 1021 spins/g and 1.33 × 1021 spins/g, respectively, with the same reaction time. Meanwhile, the olefins conjugated with aromatic rings shown more obvious effect on the generation of free radicals. Olefinic compounds can lead to a high generation rate of free radicals and significantly high stable free radical concentration in the polymerizing system which then promote the formation of disordered carbon materials. Besides, plenty of fine particles appeared between mesophase spheres with the addition of olefinic hydrocarbons, and then impeded the coalescence between mesophase spheres. Effect mechanism for olefin on the development of carbonaceous mesophase was proposed accordingly. In sum, the content of olefinic compounds in raw materials should be limited for reaching the requirements of the synthesis of carbon materials with superior structures, in which the content of olefinic compounds should be less than 1 wt% at least based on the research in this paper. [Display omitted] • Concentration of stable free radical varies greatly along with carbonization. • Effect of olefin on the free radical concentration is revealed for the first time. • Olefin shows great impacts on the intermediate species during carbonization. • Influence mechanism of olefin on carbonization process is proposed. • Olefin content in feedstock should be limited for high-value-added utilization. [ABSTRACT FROM AUTHOR]

[Display omitted] • A three-stage pre-treatment method for food waste (FW) adapted to incineration was proposed, and resources were recovered along with energy. • The freshwater in FW was recovered by a freeze-drying process and its availability was detected and proven. • The negative effect of the presence of lipids on the fuel properties evolution of torrefaction products was investigated. • The fuel properties and combustion performance of coal-like torrefaction products from FW were well evaluated. As of 2020, the annual generation of municipal solid waste (MSW) in China has surged to 235.12 Mt, and food waste (FW) accounts for more than 60 %. The most common treatment method is incineration, which accounts for 62.13 %. This research proposes a three-stage pretreatment method for FW that is suitable for incineration while recovering by-products and energy from the pretreatment process. The first stage is dehydration; as compared to hot air drying (HAD) processes, freeze drying (FD) exhibits a higher dehydration and oil preservation rate, allowing for the preservation of organic matter content and the recovery of freshwater resources from FW. The second stage is oil recovery; the FW extracted oil (FWEO) can be used to produce biodiesel, and this stage also helps to improve the effectiveness of the subsequent torrefaction process. The third stage improves the energy and fuel characteristics of the organic residue of FW and enhances the combustion performance by optimizing the torrefaction temperature. The solid fuel obtained at a torrefaction temperature of 350 °C shows the best combustion performance, with a solid yield of 35.76 %, a torrefaction temperature of 300 °C might be chosen to further improve the solid yield. [ABSTRACT FROM AUTHOR]

• A framework for short-term risk and economic dispatch of HTWPS considering spinning reserve is proposed. • Synchronic peak-shaving strategy is proposed to reduce hydropower fluctuation and improve hydropower peak shaving. • SR reasonable arrangement is helpful to reduce the risk and cost of the hybrid system. • The incoming water and comprehensive utilization significantly affect the risk and economy of HTWPS. The objective of the traditional dispatching model of multi-energy systems is to seek the most economical scheduling mode, while ignoring the operating risk caused by inaccurate predictions of wind and PV power. Given this, this paper proposes a framework for the short-term risk and economic dispatch of the hydro-thermal-wind-PV hybrid system (HTWPS). First, a quantile regression method and multivariate Gaussian distribution are adopted to generate wind-PV scenarios. Then, a short-term risk and economic dispatching model of the HTWPS considering spinning reserve (SR) requirements is established to minimize the operating risk and cost. Finally, a synchronic peak-shaving strategy for hydropower stations is developed to determine reasonable hydropower generation plans in model solving. The proposed framework is applied to China's Qinghai grid. The results show that: (1) As comprehensive utilization flow rises, the cost and risk drop sharply in the dry season, but almost keep unchanged in the wet season constrained by hydropower SR boundary. (2) The power abandonment risk in the dry season is high due to the low hydropower generation capacity induced by limited runoff. The power abandonment and shortage risk are mainly subject to the hydropower SR boundary in the wet season. (3) Compared with the operating mode with hydropower SR alone, the comprehensive risk decreases by 10.6%, and the comprehensive cost rises by 5.8% under the operating mode with hydro and thermal power SR (HTSR) in the dry season. The comprehensive risk decreases by 51.4%, and the comprehensive cost increases by 172.8% under HTSR in the wet season. [ABSTRACT FROM AUTHOR]

Resveratrol (Res) has drawn great interests due to its potential benefits on human health, while applications of Res in nutritional and pharmaceutical fields are limited due to its poor water solubility, low bioavailability and instability. Here in this work, an advanced anti-solvent precipitation strategy, flash nanoprecipitation (FNP), has been applied for controlled fabrication of Res-loaded nanoparticles (NPs). Specifically, solvent streams containing Res and zein (stabilizing polymers) blend with anti-solvent streams in a multi-inlet vortex mixer (MIVM), which enables fast mixing on the order of millisecond and creates kinetically trapped NPs. The efficient fabrication and effects of different control factors on the particle formation and properties have been fully explored by means of static and dynamic light scattering, TEM, fourier-transform infrared and fluorescence. The obtained NPs exhibit tunable sizes from 50 to 108 nm with narrow size distribution (PDI ∼ 0.1), enhanced drug loading content (30–57 %), improved stability and antioxidant capacity. These satisfied properties are assigned to the kinetic control of FNP, our study therefore develops a facile and alternative fabrication strategy for controlled preparation of Res-loaded NPs. [Display omitted] • Resveratrol-loaded nanoparticles with controlled size and properties has been fabricated through flash nanoprecipitation (FNP). • This strategy features rapid processing, continuous production, and available control on particle size and properties. • The obtained NPs exhibit well-tuned particle sizes (50-108 nm, PDI∼0.1), enhanced DLC (30-57 %) and antioxidant capacity. [ABSTRACT FROM AUTHOR]