bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preferential export of permafrost-derived organic matter as retrogressive thaw slumping intensifies
Authors: Bröder Lisa , Keskitalo Kirsi , Zolkos Scott , Shakil Sarah , Tank Suzanne E , Kokelj Steve V , Tesi Tommaso , Van Dongen Bart E , Haghipour Negar , Eglinton Timothy I , Vonk Jorien E 
Published: March 2021

Abstract
Enhanced warming of the Northern high latitudes has intensified thermokarst processes throughout the permafrost zone. Retrogressive thaw slumps (RTS), where thaw-driven erosion caused by ground ice melt creates terrain disturbances extending over tens of hectares, represent particularly dynamic thermokarst features. Biogeochemical transformation of the mobilized substrate may release CO2 to the atmosphere and impact downstream ecosystems, yet its fate remains unclear. The Peel Plateau in northwestern Canada hosts some of the largest RTS features in the Arctic. Here, thick deposits of Pleistocene-aged glacial tills are overlain by a thinner layer of relatively organic-rich Holocene-aged permafrost that aggraded upward following deeper thaw and soil development during the early Holocene warm period. In this study, we characterize exposed soil layers and the mobilized material by analysing sediment properties and organic matter composition in active layer, Holocene and Pleistocene permafrost, recently thawed debris deposits and fresh deposits of slump outflow from four separate RTS features. We found that organic matter content, radiocarbon age and biomarker concentrations in debris and outflow deposits from all four sites were most similar to permafrost soils, with a lesser influence of the organic-rich active layer. Lipid biomarkers suggested a significant contribution of petrogenic carbon especially in Pleistocene permafrost. Active layer samples contained abundant intrinsically labile macromolecular components (polysaccharides, lignin markers, phenolic and N-containing compounds). All other samples were dominated by degraded organic constituents. Active layer soils, although heterogeneous, also had the highest median grain sizes, whereas debris and runoff deposits consisted of finer mineral grains and were generally more homogeneous, similar to permafrost. We thus infer that both organic matter degradation and hydrodynamic sorting during transport affect the mobilized material. Determining the relative magnitude of these two processes will be crucial to better assess the role of intensifying RTS activity in CO2 release and ecosystem carbon fluxes.
Saving the world from your couch: the heterogeneous medium-run benefits of COVID-19 lockdowns on air pollution
Authors: Bonardi Jean-Philippe , Gallea Quentin , Kalanoski Dimitrija , Lalive Rafael , Madhok Raahil , Noack Frederik , Rohner Dominic , Sonno Tommaso 
Published: March 2021

Abstract
In Spring 2020, COVID-19 led to an unprecedented halt in public and economic life across the globe. In an otherwise tragic time, this provides a unique natural experiment to investigate the environmental impact of such a (temporary) ‘de-globalization’. Here, we estimate the medium-run impact of a battery of COVID-19 related lockdown measures on air quality across 162 countries, going beyond the existing short-run estimates from a limited number of countries. In doing so, we leverage a new dataset categorizing lockdown measures and tracking their implementation and release, extending to 31 August 2020. We find that domestic and international lockdown measures overall led to a decline in PM2.5 pollution by 45% and 35%, respectively. This substantial impact persists in the medium-run, even as lockdowns are lifted, there is, however, substantial heterogeneity across different types of lockdown measures, different countries, and different sources of pollution. We show that some country trajectories are much more appealing (with fewer COVID-19 casualties, less economic downturn and bigger pollution reductions) than others. Our results have important policy implications and highlight the potential to ‘build back better’ a sustainable economy where pollution can be curbed in a less economically costly way than during the COVID-19 pandemic.
A review of trends and drivers of greenhouse gas emissions by sector from 1990 to 2018
Authors: Lamb William F , Wiedmann Thomas , Pongratz Julia , Andrew Robbie , Crippa Monica , Olivier Jos G J , Wiedenhofer Dominik , Mattioli Giulio , Khourdajie Alaa Al , House Jo , Pachauri Shonali , Figueroa Maria , Saheb Yamina , Slade Raphael , Hubacek Klaus , Sun Laixiang , Ribeiro Suzana Kahn , Khennas Smail , de la Rue du Can Stephane , Chapungu Lazarus , Davis Steven J , Bashmakov Igor , Dai Hancheng , Dhakal Shobhakar , Tan Xianchun , Geng Yong , Gu Baihe , Minx Jan 
Published: March 2021

AbstractGlobal greenhouse gas (GHG) emissions can be traced to five economic sectors: energy, industry, buildings, transport and AFOLU (agriculture, forestry and other land uses). In this topical review, we synthesise the literature to explain recent trends in global and regional emissions in each of these sectors. To contextualise our review, we present estimates of GHG emissions trends by sector from 1990 to 2018, describing the major sources of emissions growth, stability and decline across ten global regions. Overall, the literature and data emphasise that progress towards reducing GHG emissions has been limited. The prominent global pattern is a continuation of underlying drivers with few signs of emerging limits to demand, nor of a deep shift towards the delivery of low and zero carbon services across sectors. We observe a moderate decarbonisation of energy systems in Europe and North America, driven by fuel switching and the increasing penetration of renewables. By contrast, in rapidly industrialising regions, fossil-based energy systems have continuously expanded, only very recently slowing down in their growth. Strong demand for materials, floor area, energy services and travel have driven emissions growth in the industry, buildings and transport sectors, particularly in Eastern Asia, Southern Asia and South-East Asia. An expansion of agriculture into carbon-dense tropical forest areas has driven recent increases in AFOLU emissions in Latin America, South-East Asia and Africa. Identifying, understanding, and tackling the most persistent and climate-damaging trends across sectors is a fundamental concern for research and policy as humanity treads deeper into the Anthropocene.
Network attack risk assessment of power grid CPS System based on attacker’s perspective
Authors: Wang Tao , Yang Tianmeng , Pan Xiao , Meng Yuan , Li Hua , Chang Peng 
Published: March 2021

Abstract
Network attack is one of the hidden dangers affecting the safe and stable operation of power system. In this paper, a potential attack path is established through association algorithm, and the selection probability of the attack path is analysed comprehensively considering the attacker’s ability, the characteristics of the attack behavior and the characteristics of the target network, and then an improved directed acyclic network attack probability attack graph is established. At the same time, the impact factors of attack action layer and attack target layer are established from the information side and the physical side, and then the incidence of the attack on the whole CPS system is analysed quantitatively, which improves the comprehensiveness and accuracy of the impact consequence analysis of network attacks. Through the above steps, the potential attack path and the risk value of the system are obtained, and the risk level of the CPS system under the current attack is determined by the fuzzy evaluation method.
Effects of different amendments on Lead and Cadmium in contaminated farmland soils around lead-zinc mines
Authors: Liu Ying , Yang Xiaomao , Zeng Hui , Zhao Zhenye , Xu Tingting , Zheng Ruibin 
Published: March 2021

Abstract
In order to provided a theoretical reference for the passive remediation of the farmland contaminated by cadmium and lead, eighteen different materials include lime kind agent, phosphate, iron oxide and clay minerals were used as the soil heavy metal passivators. Results showed that adding the passivators Ca(OH)2, sodium pyrophosphate, CaHPO4 could significantly decrease the available cadmium in soils, and the optimal concentrations were 2%, 1% and 2%, respectively. The passivators FeCl3, NaH2PO4 and CaHPO4 could significantly decrease the available lead in soils, and the optimal concentrations were 3%, 2% and 2%, respectively.
The Potentiality of Crassocephalum crepidioides for Phytoremediation of Cd Contaminated Soil under the Application of EDTA
Authors: Cheng Dandan , Liu Xixi , Zhang Hui , Zou Ziwei , Zhu Guangxu 
Published: March 2021

Abstract
Aiming to identify measures to improve the cadmium (Cd) extraction efficiency of Crassocephalum crepidioides on Cd contaminated soil, a pot experiment was conducted to investigate plant growth and Cd accumulation in Crassocephalum crepidioides enhanced by ethylenediaminetetraacetic acid (EDTA) application. The results revealed that plant growth was inhibited and biomass decreased while treated with EDTA. The application of EDTA activated Cd in soil, thus increasing the Cd concentration of leaf, stem and root of Crassocephalum crepidioides by 10%∼91%, 13%∼98%, 20∼93%, respectively. According to the Cd extraction amount by the plant, potential phytoremediation capability of Crassocephalum crepidioides in Cd contaminated soils would be enhanced effectively with application of 4 mmol⋅kg−1 EDTA, however, the environmental risks should be considered synthetically when using. This study can provide a basis for the remediation of Cd contaminated soil.
Effects of Biochar and AM Fungi on Growth, Mineral Elements and Cadmium Uptake of Mulberry under Cadmium Stress
Authors: Guo Xiongfei , Li Yunxiang 
Published: March 2021

Abstract
In order to explore the synergistic effect of biochar and arbuscular mycorrhizal (AM) fungi on plant growth under cadmium (Cd) stress, a pot experiment was conducted to investigate the effects of biochar application and AM fungal inoculation on mulberry (Morus alba) seedling growth, mineral element absorption, Cd uptake, soil pH and Cd availability under Cd contamination at 2 levels (0 and 4 mg⋅kg−1). The results showed that biochar application could increase the mycorrhizal infection rate of AM fungi. Biochar application and AM fungal inoculation alone or their combination could all increase plant height, biomass, mineral element content and soil pH, while reduce Cd bioavailability in soil and Cd uptake by mulberry seedlings. The effects of biochar application in increasing soil pH and N and K uptake were better compared with AM fungal inoculation. However, AM fungal inoculation presented better effects in promoting mulberry seedling growth, improving P, Ca and Mg absorption by mulberry seedlings, and reducing Cd availability in soil and Cd absorption by mulberry seedlings. The combination of biochar application and AM fungal inoculation obtained the best effect. Under Cd level of 4 mg⋅kg−1, the combination of biochar application and AM fungal inoculation increased plant height and N, P, K, Ca and Mg contents in mulberry leaves by 43.28%, 125.56%, 178.48%, 3.63%, 181.04% and 128.04%, respectively. While, Cd concentration in the roots, stems and leaves of mulberry seedlings decreased by 46.48%, 67.86% and 58.97%, respectively. Moreover, pH increased by 5.33%, while Cd availability in soil decreased by 69.53%. In conclusion, biochar and AM fungi alone or their combination can all reduce Cd stress, and promote plant growth and mineral element absorption. The combination of biochar and AM fungi presents the best effect. Biochar combined with AM fungi can be used as an effective measure for ecological restoration of degraded soil and agricultural production safety.
Comparative Analysis of Six Geologic Sequestration Methods
Authors: Zhao Hongmeng 
Published: March 2021

Abstract
With the extensive use of fossil fuels[1] since the advent of the industrial age, the amount of carbon dioxide emitted is also increasing dramatically, which has also led to a severe greenhouse effect[2]. The method of carbon capture and carbon sequestration[3] proposed in recent years is a good way to deal with too much carbon dioxide. However, Carbon Sequestration is a new idea without enough practice and verification, and its development is not perfect yet. This paper reviews six commonly used geological Carbon dioxide storage methods and compares the advantages and disadvantages of them. It can be concluded that hydrodynamic force sequestration is the most suitable, effective and promising method of Carbon sequestration[4]. This study aims to provide scientific suggestions and theoretical basis for the future development of carbon sequestration, and it also provides effective help and support for environmental protection.
Research on Emission Standards and Control Technology of Heavy Commercial Diesel Vehicles
Authors: Xiaomin Liu , Zhaoming Wang , Yezhen Li , Qifeng Liu 
Published: March 2021

Abstract
More than 70% of the pollutants produced by heavy commercial diesel vehicles are from exhaust, which contains a large number of harmful substances. These substances are discharged into the air with vehicle exhaust, polluting the environment. In addition, the emission height of automobile exhaust is mainly between 0.3 meters and 2 meters, which is exactly the breathing range of human body, thus posing a threat to human health. At present, China has improved the management of exhaust emission testing of heavy commercial diesel engines, and the emission standard has been gradually raised from the national V standard to the national VI standard. This paper mainly expounds the hazards of different pollutants, studies on the national emission standards and control technologies, and provides references for the related industry research.
Study and analysis of arsenic adsorption during sludge incineration
Authors: Liu Dengdeng , Ren Xiaohan 
Published: March 2021

AbstractThis paper studies the mechanism of arsenic adsorption by different adsorbents during sludge incineration. The mechanism of arsenic adsorption in the sludge incineration process was studied in a vertical furnace. The arsenic adsorption performance of CaCO3and Fe2O3at different temperatures was studied. When the temperature is 900°C, the overall adsorption performance is the best. Therefore, the arsenic adsorption performance of Al2O3, molecular sieve and its metal load at 900°C is further studied for comparison. The research results show that: the optimal adsorption temperature of CaCO3is 900°C, the optimal adsorption temperature of Fe2O3is 800°C, and the adsorption performance of CaCO3is better than Fe2O3. Ca2+: Al3+=0.5 and Fe3+: Al3+=0.4 are close to the adsorption saturation state when Al2O3adsorbs arsenic at 900°C. When the molecular sieve adsorbs arsenic at 900°C, the adsorption effect is best when the molecular sieve is 10X, Ca2+: Al3+=0.8 and Fe3+: Al3+=0.6 are close to the adsorption saturation state.
Simulation of the shear effect in the ultrasonic descaling of the heat exchanger which produces viscoelastic soft scale
Authors: Ma Tao , Wang Hehui 
Published: March 2021

Abstract
The research object of this paper is a heat exchanger that produces viscoelastic soft scale in a chemical company. The finite element software ANSYS is used to simulate and analyse the shear effect in the ultrasonic descaling process. In the research, the parameters of the Prony series model of viscoelastic materials were obtained by fitting the relaxation modulus data, then the shear stress on the interface between the scale and shell of the heat exchanger was calculated by transient dynamic method, and finally the influence of ultrasonic parameters on the shear effect strength was explored by setting multiple working conditions. The results show that the strength of shear effect increases with the increase of ultrasonic amplitude or the decrease of ultrasonic frequency, so it is advisable to use the high-amplitude and long-pulse ultrasonic wave for scale removal. The simulation method and conclusion in this paper can provide reference for ultrasonic parameter selection in descaling of heat exchange equipment.
Fenton-like reaction-induced degradation of Methylene Blue by using supermacroporous ferrimagnetic nanorings
Authors: Jiao Xibin , Li Jinghua , Wang Chaojie , Shi Jiahua , Jiao Junbo , Zhang Jianbo , Lei Qiuwei , Xiao Zhenqun , Ye Jiangxue , Guo Shouwei 
Published: March 2021

Abstract
The removal and/or degradation of methylene blue (MB) from dyestuff wastewater has attracted widespread attention. Utilization of environmental purification nanomaterials is an effective means in the field of environmental remediation, and degradation efficiency under different circumstances is always a high priority for the nanoagents. In this study, uniform supermacroporous ferrimagnetic Fe3O4 nanorings (sFe3O4-NRs) were fabricated for high-efficiency MB degradation. Typically, the sFe3O4-NRs were prepared by a convenient hydrothermal method. Subsequently, the morphology structure of the sFe3O4-NRs was characterized by scanning electron microscope (SEM), transmission electron microscope (TEM) and highresolution transmission electron microscopy (HRTEM), respectively. Next, a Fenton-like reaction-induced MB degradation was performed in the present of sFe3O4-NR nanocatalysator and hydrogen peroxide (H2O2). Meanwhile, the sFe3O4-NRs showed excellent Fenton-catalytic activity for degradation of MB in a wide range of pH (3-11). Moreover, because of the magnetic property of the sFe3O4-NRs (saturation magnetization of 34.26 emu/g), the used sFe3O4-NR could be rapidly separated from the reaction medium by using a magnet, the sFe3O4-NR resented relative high catalytic activity even after 10 times reuse. The main conclusion from this work was that the as-synthesized sFe3O4-NRs nanoagent was a type of desirable Fenton catalyst to degenerate MB from wastewater.
Study on microbial remediation of heavy metal contaminated soil
Authors: Jiaming Qin , Biguang Jiang , Xiaolong Nan , Rui Xu , Youyu He , Guoqing Jiang , Jinning Qin , Yongbin Yang , Qian Li 
Published: March 2021

Abstract
This paper studied the leaching effect of various strains on the heavy metal contaminated soil around the mining area of Dong’an County, Hunan Province. By measuring the form of heavy metals of antimony and arsenic in the soil and the concentration of heavy metals in the solution, the remediation effect of microorganisms in different pH conditions and different soil environments on the heavy metal contaminated soil was explored. The results showed that Acidithiobacillus thiooxidans(A.c) and Acidithiobacillus thiooxidans(A.t) had better leaching effect. Under the initial conditions of pH equal to 1, 10% bacteria content and 10 g/L S, the active metal components in the soil could be dissolved. The results showed that microorganism could remediate the soil contaminated with heavy metals and make the available metal components in the soil reach the safety standard.
Experimental study on deflection of recycled concrete twoway slab under concentrated load
Authors: Hu Pengjie , Fang Guangxiu , Li Zhongwei 
Published: March 2021

Abstract
In order to study the deflection calculation method of recycled concrete two-way slab under concentrated load, a full-scale model of recycled concrete two-way slab was designed, and the replacement rate of recycled coarse aggregate was 30%. Through the loading test, the failure mode of the two-way slab was observed, and the test data of the whole process curve of the deflection changing with the load value and the development of the mid-span deflection were obtained. Based on the current theoretical formula, this paper uses Origin software to simulate the deflection of recycled concrete two-way slabs under concentrated load on the basis of comparing the deflection test value and the theoretical calculation value, and proposes a correction coefficient for the two-way slab deflection calculation. For the proposed two-way plate deflection calculation correction factor, the existing test data is used to verify it. The results show that the deflection value calculated according to the method in this paper is relatively close to the test value. The research results can provide reference for follow-up experiments.
Study on formation mechanism of ground fissures induced by underground engineering construction in Chongqing area
Authors: Hu Ting , Zhang Jinhao , Li Qingshan , Wang Wei , Liu Jia 
Published: March 2021

Abstract
The geological structure of Chongqing area is complex, many small and mediumsized faults are developed in the axis of anticline fold, and there are many structural fissures in rock strata, and karst landform is developed in some areas. With the development of economy, the construction of underground engineering is increasing, which leads to the rapid decline of groundwater and construction vibration, resulting in a large number of uneven ground settlement, and the formation of ground fissures. This paper introduces the various forms of ground fissures, analyzes the formation process of uneven ground settlement area in the process of underground engineering construction, establishes the stress model of soil surface cracks based on the fracture mechanics theory of cohesive soil cracks, uses the fracture judgment of I-II composite cracks to determine whether the cracks expand or not, and uses the formula of soil cracking angle to calculate its propagation direction, and preliminarily explains the fracture mechanism of soil in the ground fissure area. It provides reference for the further study of corresponding disaster mechanism.
Study on the Migration of Manganese in the Hyporheic Zone of a Reservoir
Authors: Yingming Feng 
Published: March 2021

Abstract
In order to study the laws of the spatial change of manganese in hyporheic zone, this paper takes Reservoir A as the actual research object, and analyzes the migration and change mechanism of manganese in the hyporheic zone by means of field sampling and data collection. The results show that the manganese content in the hyporheic zone of Reservoir A is changed rapidly after impoundment, and a new hyporheic zone is formed. When the hyporheic zone is closer to the surface water of the reservoir, the manganese content will stabilize faster. In the vertical direction, the hyporheic zone has a de-oxidation effect on manganese. The de-oxidation effects on manganese during wet period and dry period are 19.2% and 13.7% respectively. Within the hyporheic zone, the change of manganese content decreases gradually; while outside the hyporheic zone, the change of manganese contents increases gradually from the top to the bottom.
Calculation Method of Deflection Recycled Concrete Two-way Composite Under Concentrated Load
Authors: Li Zhongwei , Fang Guangxiu , Hu Pengjie 
Published: March 2021

Abstract
In this experiment, a full-scale model of recycled concrete two-way laminated slab with a 30% replacement rate of recycled coarse aggregate was used. Through concentrated load loading tests, the mechanical properties of recycled concrete two-way laminated slabs were studied, it includes bearing capacity, crack distribution, stiffness and deflection. According to its stress characteristics and on the basis of the current specifications, the stiffness formula is adjusted, and the deflection value is calculated theoretically. By comparing the measured value with the theoretical calculation value, the modified formula of the deflection of recycled concrete two-way composite slab is put forward.