Cenozoic India-Asia collision driven by mantle dragging the cratonic root.

The driving force behind the Cenozoic India-Asia collision remains elusive. Using global-scale geodynamic modeling, we find that the continuous motion of the Indian plate is driven by a prominent upper-mantle flow pushing the thick Indian lithospheric root, originated from the northward rollover of the detached Neo-Tethyan slab and sinking slabs below East Asia. The maximum mantle drag occurs within the strong Indian lithosphere and is comparable in magnitude to that of slab pull (1013 N m-1). The thick cratonic root enhances both lithosphere-asthenosphere coupling and upper-plate compressional stress, thereby sustaining the topography of Tibetan Plateau. We show that the calculated resistant force from the India-Asia plate boundary is also close to that due to the gravitational potential energy of Tibetan Plateau. Here, we demonstrate that this mantle flow is key for the formation of the Tibetan Plateau and represents part of a hemispheric convergent flow pattern centered on central Asia.

The role of plume-lithosphere interaction in Hawaii-Emperor chain formation.

Paleolatitudes of volcanic rocks reveal that prominent changes in volcanic trend of the Hawaii-Emperor hotspot chain represent meridional migration of the magma source. However, models assuming latitudinal plume migration fail to explain the observed age distribution, rock composition, and erratic paleolatitude changes of the oldest Emperor seamounts. Here we use data-assimilation models to better reproduce the Hawaii-Emperor hotspot track by systematically considering plate reconstruction, plume-lithosphere interaction, and simplified melt generation and migration. Our results show that plate drag and plume-ridge interaction are both important in explaining the observed seamount ages. These shallow dynamic processes could account for 50% of the observed paleolatitude's secular reduction and erratic variations over time, where the necessary southward migration of the Hawaiian plume root is significantly less than previously thought. We conclude that plume-lithosphere interaction represents a common mechanism in affecting hotspot track, and has important implications in understanding mantle dynamics and plate reference frames.

Research progress on pretreatment technology for the analysis of amphetamine biological samples.

Sample pretreatment technology is crucial for drug analysis and detection, because the effect of sample pretreatment directly determinates the final analysis results. In recent years, with the continuous innovation of microextraction and other technologies like material preparation technologies and assistant technologies for extraction, the sample pretreatment techniques in the process of drug analysis have become more and more mature and diverse. This article takes amphetamine (AM) or methamphetamine as an example to review the recent development of pretreatment methods for AM-containing biological samples from the perspectives of extraction techniques, extraction media and auxiliary technologies. Extraction techniques are summarized with the categories of contact microextraction, separate microextraction and membrane-based microextraction for better guidance of application according to their features. Prevailing and innovative extraction media including carbon-based material, silicon-based material, metal organic framework, molecularly selective materials, supramolecular solvents and ionic liquids are reviewed. Auxiliary technologies like magnetic field, electric field, microwave, ultrasound and so on which can enhance extraction efficiency and accuracy are also reviewed. In the last, prospects of the future development of pretreatment technology for the analysis of AM biological samples are provided.

Western US intraplate deformation controlled by the complex lithospheric structure.

The western United States is one of Earth's most tectonically active regions, characterized by extensive crustal deformation through intraplate earthquakes and geodetic motion. Such intracontinental deformation is usually ascribed to plate boundary forces, lithospheric body forces, and/or viscous drag from mantle flow. However, their relative importance in driving crustal deformation remains controversial due to inconsistent assumptions on crustal and mantle structures in prior estimations. Here, we utilize a fully dynamic three-dimensional modeling framework with data assimilation to simultaneously compute lithospheric and convective mantle dynamics within the western United States. This approach allows for quantitative estimations of crustal deformation while accounting for the realistic three-dimensional lithospheric structure. Our results show the critical role of the complex lithospheric structure in governing intraplate deformation. Particularly, the interaction between the asthenospheric flow and lithospheric thickness step along the eastern boundary of the Basin and Range represents a key driving mechanism for localized crustal deformation and seismicity.

An emerging plume head interacting with the Hawaiian plume tail.

The Hawaiian-Emperor seamount chain has shown two subparallel geographical and geochemical volcanic trends, Loa and Kea, since ∼5 Ma, for which numerous models have been proposed that usually involve a single mantle plume sampling different compositional sources of the deep or shallow mantle. However, both the dramatically increased eruption rate of the Hawaiian hotspot since ∼5 Ma and the nearly simultaneous southward bending of the Hawaiian chain remain unexplained. Here, we propose a plume-plume interaction model where the compositionally depleted Kea trend represents the original Hawaiian plume tail and the relatively enriched Loa trend represents an emerging plume head southeast of the Hawaiian plume tail. Geodynamic modeling further suggests that the interaction between the existing Hawaiian plume tail and the emerging Loa plume head is responsible for the southward bending of the Hawaiian chain. We show that the arrival of the new plume head also dramatically increases the eruption rate along the hotspot track. We suggest that this double-plume scenario may also represent an important mechanism for the formation of other hotspot tracks in the Pacific plate, likely reflecting a dynamic reorganization of the lowermost mantle.

Effect of residence time during hydrothermal carbonization of biogas digestate on the combustion characteristics of hydrochar and the biogas production of process water.

The biogas digestate from anaerobic digestion of cow manure and energy crops was treated by hydrothermal carbonization (HTC) at 210 °C for 0.5 to 5 h to understand the effect of HTC residence time on the combustion characteristics of hydrochar and the biogas production of process water. The increase in HTC residence time slightly reduced the higher heating values (16.3-16.0 MJ/kg) but improved most slagging and fouling indices of the hydrochar. However, the slagging and fouling during hydrochar combustion were almost impossible to avoid. The specific methane yield of the process water was not significantly influenced by the HTC residence time. Energy assessment demonstrated that HTC for 0.5 h achieved the highest process efficiency and net energy gain when the combustion energy was obtained from hydrochar and CH4 (from process water). Therefore, the HTC condition of 210 °C, 0.5 h is suggested to valorize biogas digestate for energy production.

Towards the Properties of Different Biomass-Derived Proteins via Various Extraction Methods.

This study selected three representative protein-rich biomass-brewer's spent grain (BSG), pasture grass (PG), and cyanobacteria (Arthrospira platensis; AP) for protein extraction with different extraction methods (alkaline treatment, aqueous extraction, and subcritical water extraction). The yield, purity, molecular weight, oil-water interfacial tension, and thermal stability of the obtained proteins derived from different biomass and extraction methods were comprehensively characterized and compared. In the view of protein yield and purity, alkaline treatment was found optimal for BSG (21.4 and 60.2 wt.%, respectively) and AP (55.5 and 68.8 wt.%, respectively). With the decreased oil-water interfacial tension, the proteins from all biomass showed the potential to be emulsifier. BSG and AP protein obtained with chemical treatment presented excellent thermal stability. As a novel method, subcritical water extraction is promising in recovering protein from all three biomass with the comparable yield and purity as alkaline treatment. Furthermore, the hydrolyzed protein with lower molecular weight by subcritical water could promote its functions of foaming and emulsifying.

Hydrothermal carbonization of biogas digestate: Effect of digestate origin and process conditions.

Hydrothermal carbonization (HTC) solids were produced in a 250-ml batch reactor from three different digestates at varying temperatures (170, 190, 210, 230, and 250 °C) and 2 and 5 h reaction time. Three potential feedstocks of biogas plants were tested: organic household waste, cow manure, and energy crops. The proximate composition, elemental composition, heating values, and thermal stability of the HTC solids were characterized. The dry ash-free basis yields and carbon recovery of HTC solids decreased with increasing HTC temperature and time. The HTC solids from energy crop digestate had the highest yields (dry ash-free basis) except at the temperature of 250 °C. Increased HTC severity was found to have a positive effect on the dry basis carbon content and leads to a higher heating values (HHV) of cow manure digestate HTC solids. The preferred reaction condition for organic household waste digestate and energy crop digestate HTC solids was found to be 210 °C for 5 h, because of the highest HHV (dry basis) and the overall combustion performance was reached. Enhancing HTC temperature increased the peak intensity of functional groups of cow manure digestate HTC solids. Scanning electron microscopy imaging showed the fibrous structure of the plants from the digestates was mostly deconstructed at 250 °C-5 h. Experimental results indicated that both digestate origin and HTC condition influenced the properties of the HTC solids.

Characterisation of biochar from maize residues produced in a self-purging pyrolysis reactor.

Response surface methodology was used to optimise pyrolysis conditions to produce biochar from maize residues (cobs, husks, leaves and stalks). The aim was to obtain biochar with good potential as an additive for composting. Mathematical models were developed to explain the experimental responses of volatile matter content (VM), ash content (AC), pH and electrical conductivity (EC) to the operating parameters such as temperature, heating rate and holding time. The temperature had the most significant influence on biochar properties. AC, pH and EC significantly increased (p < 0.05) with increasing temperature, while the VM decreased. The holding time showed less effect on the responses, while the heating rate had insubstantial effect. Under the optimal conditions, the husk and leaf biochar had higher AC (11.42 and 26.55%), pH (10.96 and 11.51), and EC (12.37 and 6.79 mS/cm), but lower VM (7.38 and 8.39%) than those of cob and stalk biochar.

Effects of different biofilm carriers on biogas production during anaerobic digestion of corn straw.

This study investigated the performance of anaerobic digestion systems using four types of fibrous biofilm carriers, a polypropylene, a polyester, a polyamide, and a polyurethane fiber material. The biogas and methane production, pH, chemical oxygen demand, total solids content, volatile solids content, residual coenzyme F420, and microbial community compositions were determined during the experimental runs. Furthermore, scanning electron microscopy was employed to identify the microbial consortium and examine their attachment onto the surface of the four fibrous biofilm carriers. The polypropylene fiber system maintained the highest biogas and methane production in the reactor, which was 44.80% and 49.84% higher than that noted in the control, respectively, during the entire anaerobic fermentation cycle. Meanwhile, the polypropylene fiber system exhibited the highest TS, VS, and COD removal efficiency. The results of high-throughput sequencing indicated that the dominant species in the polypropylene fiber system were Methanoregula and Methanobacterium.