Crabs are an indispensable component of the benthic ecosystem and represent a type of seafood that is easily obtained and frequently eaten by humans. However, little is known about microplastic (MP) ...accumulation in different tissues of crabs in important fishing areas. In this study, the abundances and characteristics of MPs in different tissues of four species of wild crabs (Portunus trituberculatus, Charybdis japonica, Dorippe japonica, and Matuta planipes) were investigated across 9 sites at three important fishing grounds (Haizhou Bay, Lvsi and Yangtze River Estuary fishing grounds) in China. Crabs from all sites were found to contain MPs, with a total detection rate of 89.34%. The MP abundance in crabs from all sites ranged from 2.00 ± 2.00 to 9.81 ± 8.08 items/individual and 0.80 ± 1.09 to 22.71 ± 24.56 items/g wet weight. The abundance of MPs exponentially increased with decreasing MP size. The MPs were dominated by fibers in terms of shape, black-gray and blue-green in terms of color and cellophane in terms of composition. MPs were found in the gills and guts of the crabs, but not in the muscles. The abundance and size of the MPs in the guts were significantly higher than those in the gills, but there was no significant difference in color or shape. In addition, crab eating patterns have a significant impact on the abundance of MPs in different species. The abundance of MPs in the saprophytic crabs was significantly higher than that in the predatory crabs. MP contamination in crabs is worthy of attention for human health and the stability of marine ecosystems.
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•Microplastics were found in the guts and gills of crabs, but not in the muscles.•The abundance and size of the MPs in the guts were significantly higher than those in the gills.•Eating pattern plays an important role in the accumulation of MP by crabs.
•A new stress invariant based isotropic ductile fracture criterion is developed.•The criterion is further extended to describe the direction dependency of ductile fracture.•A new out-of-plane shear ...specimen is proposed to study the through-thickness property of the sheet.•Hybrid experimental-numerical method is used to determine fracture strains from in-plane to out-of-plane.•The new criterion is able to predict the anisotropic fracture behaviors of a DP980 sheet with high accuracy.
Sheet metals usually exhibit varying degrees of anisotropy due to formation of texture during rolling process. The grain structures and distributions in sheet normal direction may also be different from that within the sheet plane. For example, martensite banding structures are usually observed in the middle of thickness for advanced high strength steels. The particular martensite morphology and inhomogeneous distribution will greatly affect the deformation and fracture behavior under out-of-plane direction. It is necessary to model the anisotropic fracture of sheet metals from in-plane to out-of-plane. In this work, a new stress invariant based ductile fracture criterion was developed by introducing a stress triaxiality and normalized third invariant dependent function h(η, ξ) and further extended to an anisotropic form through the linear transformation of stress tensor. Parametric study showed that the new anisotropic criterion can describe the direction dependency of ductile fracture in both strain and stress spaces. A series of in-plane fracture tests including tension with a central hole, notched tension, V-bending test, Nakajima test and in-plane shear as well as a new out-of-plane shear test were conducted to study the anisotropic fracture behavior of DP980 sheet metals over a variety of stress states. Hybrid experimental-numerical method is used to determine the fracture strains and the loading paths to fracture. The results show that slight in-plane anisotropy of fracture responses exists for this DP980 sheet, while the out-of-plane shear fracture stress is approximately 11% lower than that under the in-plane shear condition. The new anisotropic ductile fracture criterion is able to predict the anisotropic fracture behaviors of this DP980 sheet with high accuracy.
Sheet metals such as advanced high strength steels often exhibit varying degrees of anisotropy due to the existence of preferred orientation of their grain structures from the rolling process. While ...extensive research has been devoted to characterize and model anisotropic plasticity behavior over the past decades, only recently people began to tackle their anisotropic fracture behavior. The focus of these studies is almost always on the in-plane anisotropy, and ignores out-of-plane fracture behavior. The reasons are two-folds: (1). Sheet metal deformation during a stamping or crash application is mostly thought as in a plane stress state and modeled as such, so there is no need to consider out-of-plane fracture behavior; and (2). It is very challenging to develop experimental techniques to reliably measure out-of-plane fracture strengths for sheet metals with a thickness only about 1 mm. In this paper, we theorize, based on strong empirical evidence, that the fracture strength of a thin sheet metal in out-of-plane shear is inherently weaker than that under in-plane shear, analogous to the interlaminar properties of composite laminates. This weakness is responsible for the so-called “shear fracture” behavior, often observed during the stamping operations of advanced high strength steels when the sheet metal flows around a tight radius. A new double-notched shear specimen with shear plane perpendicular to the thickness direction is carefully designed and tested to accurately measure the out-of-plane shear fracture strength. Simulations are executed to validate the rationality of the out-of-plane shear specimen design. Test results of a DP980 sheet show that the out-of-plane shear fracture strength is indeed about 15% lower than that measured under the in-plane shear condition. A new anisotropic ductile fracture model based on linear transformation of stresses is proposed to account for the out-of-plane fracture strength for AHSS sheets. The model is calibrated with experimental data, and the fracture surface is compared to the isotropic Mohr-Coulomb (M-C) fracture model to illustrate its effectiveness.
•A new double notched sheet specimen for out-of-plane shear is proposed.•The experiments are constructed for the measurement of shear fracture strengths.•A model is extended to describe the fracture initiation under out-of-plane shear.•DP980 sheets are similar to the composite which exist the inherent weakness.•It provides a reasonable and reliable understanding for early fracture of AHSS.
Lithium‐oxygen batteries possess an extremely high theoretical energy density, rendering them a prime candidate for next‐generation secondary batteries. However, they still face multiple problems ...such as huge charge polarization and poor life, which lay a significant gap between laboratory research and commercial applications. In this work, we adopt 15‐crown‐5 ether (C15) as solvent to regulate the generation of discharge products in lithium‐oxygen batteries. The coronal structure endows C15 with strong affinity to Li+, firmly stabilizes the intermediate LiO2 and discharge product Li2O2. Thus, the crystalline Li2O2 is amorphized into easily decomposable amorphous products. The lithium‐oxygen batteries assembled with 0.5 M C15 electrolyte show an increased discharge capacity from 4.0 mAh cm−2 to 5.7 mAh cm−2 and a low charge overpotential of 0.88 V during the whole lifespan at 0.05 mA cm−2. The batteries with 1 M C15 electrolyte can cycle stably for 140 cycles. Furthermore, the amorphous characteristic of Li2O2 product is preserved when matched with redox mediators such as LiI, with the charge polarization further decreasing to 0.74 V over a cycle life of 190 cycles. This provides new possibilities for electrolyte design to promote Li2O2 amorphization and reduce charge overpotential in lithium‐oxygen batteries.
The coronal 15‐crown‐5 ether shows strong affinity towards Li+, which stabilizes not only the intermediate LiO2 but also the resulting product. This transforms the typical crystalline Li2O2 into an amorphous state, thereby significantly reduces the product decomposition barriers. Thus, Li‐O2 batteries shows lower charge overpotential and longer lifespan.
Abstract Lithium‐oxygen batteries possess an extremely high theoretical energy density, rendering them a prime candidate for next‐generation secondary batteries. However, they still face multiple ...problems such as huge charge polarization and poor life, which lay a significant gap between laboratory research and commercial applications. In this work, we adopt 15‐crown‐5 ether (C15) as solvent to regulate the generation of discharge products in lithium‐oxygen batteries. The coronal structure endows C15 with strong affinity to Li + , firmly stabilizes the intermediate LiO 2 and discharge product Li 2 O 2 . Thus, the crystalline Li 2 O 2 is amorphized into easily decomposable amorphous products. The lithium‐oxygen batteries assembled with 0.5 M C15 electrolyte show an increased discharge capacity from 4.0 mAh cm −2 to 5.7 mAh cm −2 and a low charge overpotential of 0.88 V during the whole lifespan at 0.05 mA cm −2 . The batteries with 1 M C15 electrolyte can cycle stably for 140 cycles. Furthermore, the amorphous characteristic of Li 2 O 2 product is preserved when matched with redox mediators such as LiI, with the charge polarization further decreasing to 0.74 V over a cycle life of 190 cycles. This provides new possibilities for electrolyte design to promote Li 2 O 2 amorphization and reduce charge overpotential in lithium‐oxygen batteries.
This paper tackles a recent challenge in identifying culprit actors, who try to hide confidential payload with steganography, among many innocent actors in social media networks. The problem is ...called steganographer detection problem and is significantly different from the traditional stego detection problem that classifies an individual object as a cover or a stego. To solve the steganographer detection problem over large-scale social media networks, this paper proposes a method that uses high-order joint features and clustering ensembles. It employs 250-D features calculated from the high-order joint matrices of Discrete Cosine Transform (DCT) coefficients of JPEG images, which indicate the dependencies of image content. Furthermore, a number of hierarchical sub-clusterings trained by the features are integrated as a clustering ensemble based on the majority voting strategy, which is used to make optimal decisions on suspicious steganographers. Experimental results show that the proposed scheme is effective and efficient in identifying potential steganographers in large-scale social media networks, and has better performance when tested against the state-of-the-art steganographic methods.
Microbial contamination and nitrite accumulation are the two major concerns in the quality control of fermented vegetables. In the present study, a lactic acid bacteria strain
ZJ316 (ZJ316) was ...inoculated during
Miq. (SSM) fermentation, and the effects of ZJ316 on the quality and bacterial community of SSM during fermentation were investigated. It was observed that ZJ316 could avoid the occurrence of the nitrite peak and maintain the nitrite content of fermented SSM at a low level. Gas chromatography-mass spectrometry (GC-MS) results suggested that ZJ316 gave good flavor to the fermented SSM. 16S rDNA sequencing showed that
was the dominant flora after ZJ316 inoculation, and the abundance of
decreased at the same time. At the level of the genus, SSM fermented by ZJ316 had a more obvious inhibitory effect on
on the 7
day compared with the naturally fermented SSM. Additionally, the effect of ZJ316-fermented SSM on gut microbiota modulation was also evaluated using an
fecal fermentation system. The results revealed that ZJ316 had a relatively subtle influence on intestinal communities with a potentially positive impact on probiotics such as
and
and a negative impact on
. Furthermore, SSM fermented by ZJ316 promoted the production of short-chain fatty acids (SCFAs) in the human intestine. These results demonstrate that
ZJ316 can be used as a good starter in the fermentation process of pickles.
The occiput-axis crossing translaminar screw (C2LAM) fixation technique can help avoid vertebral injury, while the inclusion of offset connectors can facilitate implantation. This three-dimensional ...finite element (FE) study compared the stability of C2LAM using offset connectors (C2LAM + OF) with other methods.
Occipital and cervical spine computed tomography images of a healthy 30-year-old man were selected to build the FE model. Four internal fixation instruments including occiput plate-C2 pedicle (C2P) and pars (C2Pars) screws, as well as C2LAM and C2LAM + OF were applied consecutively to the model respectively to establish four new models, which were subjected to all states of motion and physiological loads to simulate normal movement, including the four kinds of basic activities of human such as flexion, extension, lateral bending, and axial rotation. Physiological measures and comparison included the range of motion (ROM) and stress distribution in the model.
ROM between the fixation techniques was comparable, and the stability of the C2LAM + OF fixation technique was similar to that of C2P. Screw entry points, offset connectors and rods were the main stress distribution regions in the C2LAM + OF system. The mean von Mises stress of the inner wall was significantly smaller than that of the outer wall in flexion, extension, and rotation (p < 0.05); however, lateral bending was comparable, indicating a relatively small risk of damage to the inner wall.
The results of this study indicate that the C2LAM + OF fusion technique can provide sufficient stability and can be used as an alternative to C2P under special circumstances.
Abstract Lithium‐oxygen batteries possess an extremely high theoretical energy density, rendering them a prime candidate for next‐generation secondary batteries. However, they still face multiple ...problems such as huge charge polarization and poor life, which lay a significant gap between laboratory research and commercial applications. In this work, we adopt 15‐crown‐5 ether (C15) as solvent to regulate the generation of discharge products in lithium‐oxygen batteries. The coronal structure endows C15 with strong affinity to Li + , firmly stabilizes the intermediate LiO 2 and discharge product Li 2 O 2 . Thus, the crystalline Li 2 O 2 is amorphized into easily decomposable amorphous products. The lithium‐oxygen batteries assembled with 0.5 M C15 electrolyte show an increased discharge capacity from 4.0 mAh cm −2 to 5.7 mAh cm −2 and a low charge overpotential of 0.88 V during the whole lifespan at 0.05 mA cm −2 . The batteries with 1 M C15 electrolyte can cycle stably for 140 cycles. Furthermore, the amorphous characteristic of Li 2 O 2 product is preserved when matched with redox mediators such as LiI, with the charge polarization further decreasing to 0.74 V over a cycle life of 190 cycles. This provides new possibilities for electrolyte design to promote Li 2 O 2 amorphization and reduce charge overpotential in lithium‐oxygen batteries.
Lithium‐oxygen batteries possess an extremely high theoretical energy density, rendering them a prime candidate for next‐generation secondary batteries. However, they still face multiple problems ...such as huge charge polarization and poor life, which lay a significant gap between laboratory research and commercial applications. In this work, we adopt 15‐crown‐5 ether (C15) as solvent to regulate the generation of discharge products in lithium‐oxygen batteries. The coronal structure endows C15 with strong affinity to Li+, firmly stabilizes the intermediate LiO2 and discharge product Li2O2. Thus, the crystalline Li2O2 is amorphized into easily decomposable amorphous products. The lithium‐oxygen batteries assembled with 0.5 M C15 electrolyte show an increased discharge capacity from 4.0 mAh cm−2 to 5.7 mAh cm−2 and a low charge overpotential of 0.88 V during the whole lifespan at 0.05 mA cm−2. The batteries with 1 M C15 electrolyte can cycle stably for 140 cycles. Furthermore, the amorphous characteristic of Li2O2 product is preserved when matched with redox mediators such as LiI, with the charge polarization further decreasing to 0.74 V over a cycle life of 190 cycles. This provides new possibilities for electrolyte design to promote Li2O2 amorphization and reduce charge overpotential in lithium‐oxygen batteries.
The coronal 15‐crown‐5 ether shows strong affinity towards Li+, which stabilizes not only the intermediate LiO2 but also the resulting product. This transforms the typical crystalline Li2O2 into an amorphous state, thereby significantly reduces the product decomposition barriers. Thus, Li‐O2 batteries shows lower charge overpotential and longer lifespan.
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