Fracture behaviour, microstructure, and performance of various layered-structured Al2O3-TiC-WC-Co composites

In this study, layered-structured Al2O3-based composites containing WC-Co, TiC, and MgO additives were prepared using hot-pressing sintering. The best comprehensive mechanical characteristics were acquired for the sample with a layer number (NLN) of 7 and thickness ratio (ηTR) of 6. Its composite exhibited a fracture toughness of 8.5 and 8.4 MPa m1/2 in the X and Z directions, respectively. Analysis of the micro characteristics of the fracture surfaces of the Al2O3-TiC-WC-Co layered composites revealed a significant enhancement in the bending strength, which could be attributed to the mixed fracture modes in the composite, including intergranular and trans-granular modes. As the displacement increased, first, the bending stress of all the composites increased gradually, after which all the samples showed abrupt elevation in stress. The enhancement in the damage resistance of Al2O3-TiC-WC-Co layered composites could be attributed to the microscopic and macroscopic crack deflection, bridging, and partial surface bonding that occurred in the layers. Finally, a new theoretical perspective was employed to discuss the mechanism of the effect of the layered structure on the toughness of the composites

Real-Time Neural Signals of Disorder and Order Perception

Order and disorder are prevalent in everyday life, yet little is known about the neural real-time processing that occurs during the perception of disorder relative to order. In the present study, from a cognitive perspective, by adopting the ERP method, we aimed to examine the elicited real-time neural signals of disorder and order perception when participants processed physical environmental and basic visual disorder and order pictures in an irrelevant red or green rectangle detection task, and we attempted to test the hypothesis of cognitive disfluency in disorder perception. Generally, we observed that at each measured time interval, the ERPs elicited by order stimuli were more positive (less negative) in amplitude than those elicited by disorder stimuli at the frontal electrodes (represented by F7/F8, FT7/FT8, Fz, and FCz), whereas at the posterior electrodes (represented by P7/P8, PO7/PO8, Pz, and POz), the opposite was true. These data reveal for the first time the neural underpinnings of disorder and order perception, extending our understanding of the nature of disorder and order. This study also contributes to the cognitive fluency literature and indirectly expands the research on disorder and order stimuli in cognitive fluency

Treatment of Landfill Leachate Using Activated Sludge Technology: A Review

Landfill leachate contains a large amount of organic matter and ammoniacal nitrogen. As such, it has become a complex and difficult issue within the water treatment industry. The activated sludge process has been found to be a good solution with low processing costs and is now therefore the core process for leachate treatment, especially for nitrogen removal. This paper describes the characteristics and treatment of leachate. Treatment of leachate using the activated sludge process includes the removal of organic matter, ammoniacal nitrogen, and total nitrogen (TN). The core method for the removal of organic matter involves anaerobic treatment supplemented with an aerobic process. Ammoniacal nitrogen is commonly removed using a conventional aerobic treatment, and advanced TN removal is achieved using endogenous denitrification or an anaerobic ammonium oxidation (ANAMMOX) process. Since biological processes are the most economical method for TN removal, a key issue is how to tap the full potential of the activated sludge process and improve TN removal from leachate. This complex issue has been identified as the focus of current scholars, as well as an important future direction for leachate research and development

Energy absorption of variable stiffness composite thin-walled tubes on axial impacting

In order to realize the engineering application of automated fiber placement for composite laminates, a method of the variable angle fiber placement was proposed to design the tube structures of variable stiffness composites based on the quadratic Bezier curve. The axial crushing responses were simulated to investigate the energy absorption characteristics of composite tubes. The results showed that the method of the variable angle fiber placement contributed to the improvement of the energy absorption effects. The maximum crushing force efficiency of the variable stiffness composite thin-walled tubes designed by the method was 49.04% which was 106.48% higher than the constant stiffness composite tube. The results could be helpful for the process of automated fiber placement and the design of the energy absorption for composite thin-walled structures

Evolution and resource potential of Permian source rocks in the southern depression of the South Yellow Sea Basin

The Permian source rocks in the southern depression of the South Yellow Sea Basin have been proved to be fair-good source rocks. Based on the analysis of recent Paleozoic oil and gas exploration and research results, the thermal evolution and hydrocarbon generation process of Permian source rocks was analyzed by selecting appropriate geological parameters and using TSM basin simulation method, and then the potential of oil and gas resources was evaluated. The research shows that the Permian source rocks distributed in Cenozoic fault depression in the southern depression experienced a two-stage hydrocarbon generation and expulsion process. The first hydrocarbon generation and expulsion occurred from the Late Triassic to the Early-Middle Jurassic and the secondary hydrocarbon generation and expulsion mainly occurred in Paleogene. However, the Permian source rocks distributed in the uplift area only experienced the first hydrocarbon generation and expulsion process. The Permian source rocks have a total resource scale of 20.76×108 t and a resource abundance of 12.2×104 t/km2, reaching a medium abundance level, which can provide a certain material basis for the formation of oil and gas fields. The secondary hydrocarbon generation resources of the Permian source rocks in the whole southern depression account for 30.4% of the total resources, but it can reach 55% in the Cenozoic fault depression. The Cenozoic fault depression with Permian source rocks and Cenozoic source rocks developed is a favorable exploration area

Optimal Estimation Retrieval of Aerosol Fine-Mode Fraction from Ground-Based Sky Light Measurements

In this paper, the feasibility of retrieving the aerosol fine-mode fraction (FMF) from ground-based sky light measurements is investigated. An inversion algorithm, based on the optimal estimation (OE) theory, is presented to retrieve FMF from single-viewing multi-spectral radiance measurements and to evaluate the impact of utilization of near-infrared (NIR) measurements at a wavelength of 1610 nm in aerosol remote sensing. Self-consistency tests based on synthetic data produced a mean relative retrieval error of 4.5%, which represented the good performance of the OE inversion algorithm. The proposed algorithm was also performed on real data taken from field experiments in Beijing during a haze pollution event. The correlation coefficients (R) for the retrieved aerosol volume fine-mode fraction (FMFv) and optical fine-mode fraction (FMFo) against AErosol RObotic NETwork (AERONET) products were 0.94 and 0.95 respectively, and the mean residual error was 4.95%. Consequently, the inversion of FMFv and FMFo could be well constrained by single-viewing multi-spectral radiance measurement. In addition, by introducing measurements of 1610 nm wavelength into the retrieval, the validation results showed a significant improvement in the R value for FMFo (from 0.89–0.94). These results confirm the high value of NIR measurements for the retrieval of coarse mode aerosols

Provenance analysis and geological significance of Paleocene in Lishui Sag, East China Sea Shelf Basin

The provenance evolution of Paleocene is a main factor controlling the sedimentary filling characteristics of the East China Sea Shelf Basin, and is of great significance in the exploration and development of petro-bearing basins. Based on the core samples of the Paleocene of the Lishui Sag, East China Sea Shelf Basin, the systematic analysis of petrological and mineralogical characteristics was carried out. Through the study of the spatial and temporal distribution of sandstone clastic components, light and heavy mineral assemblages and related parameters, the evolution of the Paleocene provenance system in the study area and its significance for the sedimentary filling of the basin were discussed. The Paleocene clastic rocks in the Lishui Sag are mainly lithic feldspar sandstone, feldspar lithic sandstone and lithic sandstone. The sandstone is mainly moderately well-sorted, and the grains are mostly subangular or subrounded, with poor overall rounding, indicating that the structural maturity and compositional maturity are relatively lower. The light mineral assemblages of the Guifeng and Lingfeng formations of Peleocene are obviously different and show zoning features in different parts of the basin. In the central and northern parts of the western subsag, there are mainly parent rock types of cycle orogenic belts, while in the south of the western subsag, there are mainly parent rock types of cycle orogenic belts and magma arc. In the eastern subsag, there are mainly parent rock types of cycle orogenic belts. The characteristics of heavy mineral assemblages in the main horizons of the Paleocene in the study area change little. The Zhejiang-Fujian uplift belt in the west and the Yandang uplift in the east are the most important provenance areas of the Lishui Sag. The Lingfeng low uplift in the center of the basin suffered serious denudation before the deposition of the lower member of the Mingyuefeng Formation, providing local provenance for the basin. The provenance system analysis showed that when the Yueguifeng and Lingfeng formations were deposited, they were in the early and peak stages of fault depression, and the intra-basin provenance area was formed by the intra-basin fault uplift. As the upper member of the Lingfeng Formation was deposited, the basin entered the late stage of fault depression, local intra-basin provenance was no longer developed, and the main provenance system was extra-basin provenance

Vitamin D protects podocytes from autoantibodies induced injury in lupus nephritis by reducing aberrant autophagy

Abstract Subject The aim of this study was to investigate whether vitamin D plays a protective role in podocyte injury induced by autoantibodies purified from the serum of patients with lupus nephritis (LN) via reducing aberrant autophagy. Methods Autophagic activities of renal tissues of patients with LN were evaluated under transmission electronic microscope (TEM). Immunoglobulin G (IgG) from patients with LN was purified to induce human podocyte injury, and the role of vitamin D in injury was observed. Podocytes were observed under TEM, autophagic activity was evaluated by western blot analysis and quantitative real-time polymerase chain reaction, and mRFP-GFP-LC3B adenovirus was infected into human podocytes in vitro. Results Significantly higher autophagic levels were observed in patients with LN (P <0.05), and apparently greater autophagic levels in podocytes were shown (P <0.05). Among different classifications of LN, class V (n = 5), III + V (n = 5), and IV + V (n = 5) gained higher autophagic levels than class III (n = 5) and IV (n = 5). Induced autophagy, which was evident by increased LC3B-II and Beclin 1 level, caused consumption of p62, more autophagosomes observed under TEM, and more LC3B dots observed under confocal microscope in the IgG group, along with decreased nephrin expression, which suggests podocyte injury. Reduction of autophagy as well as alleviated podocyte injury was observed in the IgG+ vitamin D group. Conclusion This study demonstrates that vitamin D plays a protective role in podocyte injury induced by autoantibodies from patients with LN and appears to be a novel therapy target in LN