94 research outputs found

    MDA GAN: Adversarial-Learning-based 3-D Seismic Data Interpolation and Reconstruction for Complex Missing

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    The interpolation and reconstruction of missing traces is a crucial step in seismic data processing, moreover it is also a highly ill-posed problem, especially for complex cases such as high-ratio random discrete missing, continuous missing and missing in fault-rich or salt body surveys. These complex cases are rarely mentioned in current sparse or low-rank priorbased and deep learning-based approaches. To cope with complex missing cases, we propose Multi-Dimensional Adversarial GAN (MDA GAN), a novel 3-D GAN framework. It employs three discriminators to ensure the consistency of the reconstructed data with the original data distribution in each dimension. The feature splicing module (FSM) is designed and embedded into the generator of this framework, which automatically splices the features of the unmissing part with those of the reconstructed part (missing part), thus fully preserving the information of the unmissing part. To prevent pixel distortion in the seismic data caused by the adversarial learning process, we propose a new reconstruction loss Tanh Cross Entropy (TCE) loss to provide smoother gradients. We experimentally verified the effectiveness of the individual components of the study and then tested the method on multiple publicly available data. The method achieves reasonable reconstructions for up to 95% of random discrete missing, 100 traces of continuous missing and more complex hybrid missing. In surveys of fault-rich and salt bodies, the method can achieve promising reconstructions with up to 75% missing in each of the three directions (98.2% in total).Comment: This work has been submitted to journal for possible publication. Copyright may be transferred without notice, after which this version may no longer be accessibl

    Achieving Strong Chemical Interface and Superior Energy-Saving Capability at the Crosslinks of Rubber Composites Containing Graphene Oxide Using Thiol-Vinyl Click Chemistry

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    Rapidly developments in international transportation inevitably lead to an increase in the consumption of energy and resources. Minimizing the rolling resistance of tires in this scenario is a pressing challenge. To lower the rolling resistance of tires, enhancing the interaction between fillers and rubber molecules while improving the dispersion of fillers are required to reduce the internal mutual friction and viscous loss of rubber composites. In this study, graphene oxide (GO) was modified using γ-mercaptopropyltrimethoxysilane (MPTMS) with thiol groups. A modified GO/natural rubber (MGO/NR) masterbatch with a fine dispersion of MGO was then introduced into solution-polymerized styrene butadiene rubber (SSBR) to create an MGO/SiO2/SSBR composite. During the crosslinking process at high temperatures, a strong chemical interface interaction between the MGO and rubber molecules was formed by the thiol-vinyl click reaction. The MGO sheets also act as crosslinks to enhance the crosslinking network. The results showed that the rolling resistance of the MGO SiO2/SSBR composite was superior by 19.4% and the energy loss was reduced by 15.7% compared with that of the base SiO2/SSBR composite. Strikingly, the wear performance and wet skid resistance improved by 19% and 17.3%, respectively. These results showed a strong interface that not only improved rolling resistance performance but also contributed to balancing the “magic triangle” (the combination of wear resistance, fuel efficiency, and traction) properties of tires

    Enhanced gas barrier properties of graphene oxide/rubber composites with strong interfaces constructed by graphene oxide and sulfur

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    Constructing strong interfacial interactions and complex filler networks is crucial to establishing high gas barrier properties in rubber composites. In this research, sulfur-graphene oxide (S-GO) hybrids were prepared by in situ growth of sulfur on the surfaces of GO sheets. The S-GO hybrids were also introduced into butadiene styrene rubber (SBR) using a green method of latex compounding. Results showed that sulfur could melt and spread on the surface of the GO during the crosslinking process at high temperatures. This process prevented the aggregation of GO and resulted in a fine dispersion of GO and complex filler networks in S-GO/SBR composites. More importantly, the sulfur particles on the GO surface not only aided the crosslinking of rubber molecules, but also chemically reacted with the GO radicals generated at high temperatures. This occurred by the homolytic cleavage of oxygen-containing groups, which thereby constructed covalent interfaces between the GO and SBR molecules. Due to these strong interfaces and complex filler networks, the tensile and tear strength of S-GO/SBR composites increased by 66.2% and 26.6%, respectively, when compared with conventional GO/SBR composites. The gas permeability coefficient of S-GO/SBR composites was decreased dramatically by 50.7% and 23.3% by comparison with that of pure SBR and GO/SBR composites, respectively. The apparent improvement demonstrated that the facile and effective method used in this research may open up new opportunities for the development of multifunctional rubber crosslinking agent as well as the fabrication of rubber composites with high performance

    Insight into the effect of hospital-based prehabilitation on postoperative outcomes in patients with total knee arthroplasty: A retrospective comparative study

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    Background: Osteoarthritis (OA) has become one of the most prevalent joint diseases worldwide, leading to a growing burden of pain and disability as populations age. Although there is consistent evidence to support postoperative rehabilitation and high-intensity prehabilitation for total knee arthroplasty (TKA), the clinical outcomes of hospital-based prehabilitation remain unclear. We aimed to evaluate the effect of a hospital-based prehabilitation program on knee score (KS), function score (FS), and length of stay (LOS) among patients with knee OA after TKA. Methods: A retrospective comparative study was conducted at Renmin Hospital of Wuhan University among patients with primary knee OA. Seventy-two postopearative patients who did not undergo the prehabilitation program were included as the control group, while 68 postoperative patients who underwent the prehabilitation program were assigned to the intervention group. All patients went through the same care after TKA. The KS, FS, and pain levels were measured 5 days before surgery, immediately preceding surgery, immediately after the surgery, and at 1 week and 1 month postoperatively. LOS for each patient was recorded. Results: The new prehabilitation training program significantly improved the KS over time in the intervention group. However, no significant between-group difference was identified in the change of FS. The prehabilitation program also provided shorter LOS. Conclusions: The hospital-based prehabilitation program leads to improved recovery, as indicated by higher KS postoperatively, which may result in improved clinical outcomes of TKA

    Enhanced covalent interface, crosslinked network and gas barrier property of functionalized graphene oxide/styrene-butadiene rubber composites triggered by thiol-ene click reaction

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    The high gas barrier property of a rubber composite is of great significance for reducing the exhaust gas emissions due to tire rolling resistance and hence the contribution this factor makes to environmental protection. Enhanced covalent interfaces and crosslinked networks are crucial to the gas barrier property of rubber composites. In this research, γ-mercaptopropyltriethoxysilane (MPS) modified GO (MGO)/styrene-butadiene rubber (SBR) composites were prepared by a synergetic strategy of latex compounding method and thiol-ene click reaction. It was found that the mercapto groups in MGO reacted with the vinyl groups in SBR molecules through thiol-ene click reaction during the crosslinking process at 150 °C, thus forming strong chemical interactions at the interface in the form of GO-MPS-rubber and enhanced crosslinked networks. Meanwhile, the strong interface promoted the dispersion of MGO in SBR. The uniform dispersion of MGO, strong interface between MGO and SBR molecules and enhanced crosslinked networks resulted in improved mechanical and gas barrier properties. When filling 5 phr fillers, the tensile strength and gas barrier properties of an MGO/SBR composite improved by 19.0% and 37.5%, respectively, relative to the comparing GO/SBR composite

    Enhanced Fatigue and Durability of Carbon Black/natural rubber Composites Reinforced with Graphene Oxide and Carbon Nanotubes

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    Graphene oxide (GO) sheets and carbon nanotubes (CNTs) are of nanometer size and offer large shape factors which are beneficial in reducing crack propagation rates of composites when used in carbon black (CB) reinforced natural rubber (NR), thereby prolonging the service lives of rubber composites. In this research, CNT-CB/NR and GO-CB/NR composites were prepared by partially replacing CB with one-dimensional CNTs and two-dimensional flaky graphene oxide GO, respectively. The results showed that the complex filler dispersion in NR matrices was improved due to the isolation effect between the different fillers. The strain-induced crystallization (SIC) ability of CB/NR was effectively enhanced by the addition of both GO and CNT. The modulus at 100% strain and tear strength of the composites were also improved. More branching and deflections were observed at the crack tips of the composites and both effectively hindered crack propagation in the materials. Under uniaxial and multi-axial cyclic loading, the fatigue lives of CNT-CB/NR and GO-CB/NR composites greatly increased when compared with the fatigue lives of CB/NR composites. The GO-CB/NR composites exhibited evident advantages in respect of fatigue resistance and durability among the three composites

    Influence of graphene oxide and carbon nanotubes on the fatigue properties of silica/styrene-butadiene rubber composites under uniaxial and multiaxial cyclic loading

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    The influence of equivalent replacement of silica (SiO2) by carbon nanotubes (CNT) or graphene oxide (GO) on the microstructure, mechanical and fatigue behaviors of SiO2/styrene-butadiene rubber (SBR) composites was investigated. Results showed that the synergistic effect between CNT (or GO) and SiO2 was beneficial for the filler network and improved the mechanical properties of SBR composites. Furthermore, the introduction of CNT (or GO) led to low crack growth rates and the crack propagation tips were easy to deflection. Under multiaxial fatigue conditions, the maximum engineering stress was determined to be a reliable fatigue life predictor for SBR composites

    Lessening the hazards of Florida red tides: a common sense approach

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    © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Hoagland, P., Kirkpatrick, B., Jin, D., Kirkpatrick, G., Fleming, L. E., Ullmann, S. G., Beet, A., Hitchcock, G., Harrison, K. K., Li, Z. C., Garrison, B., Diaz, R. E., & Lovko, V. Lessening the hazards of Florida red tides: a common sense approach. Frontiers in Marine Science, 7, (2020): 538, doi:10.3389/fmars.2020.00538.In the Gulf of Mexico, especially along the southwest Florida coast, blooms of the dinoflagellate Karenia brevis are a coastal natural hazard. The organism produces a potent class of toxins, known as brevetoxins, which are released following cell lysis into ocean or estuarine waters or, upon aerosolization, into the atmosphere. When exposed to sufficient levels of brevetoxins, humans may suffer from respiratory, gastrointestinal, or neurological illnesses. The hazard has been exacerbated by the geometric growth of human populations, including both residents and tourists, along Florida’s southwest coast. Impacts to marine organisms or ecosystems also may occur, such as fish kills or deaths of protected mammals, turtles, or birds. Since the occurrence of a severe Karenia brevis bloom off the southwest Florida coast three-quarters of a century ago, there has been an ongoing debate about the best way for humans to mitigate the impacts of this hazard. Because of the importance of tourism to coastal Florida, there are incentives for businesses and governments alike to obfuscate descriptions of these blooms, leading to the social amplification of risk. We argue that policies to improve the public’s ability to understand the physical attributes of blooms, specifically risk communication policies, are to be preferred over physical, chemical, or biological controls. In particular, we argue that responses to this type of hazard must emphasize maintaining the continuity of programs of scientific research, environmental monitoring, public education, and notification. We propose a common-sense approach to risk communication, comprising a simplification of the public provision of existing sources of information to be made available on a mobile website.The research leading to these results was supported by the US National Science Foundation (NSF) under NSF Grant No. CNH 1009106. PH and DJ acknowledge the complementary support under NSF Grant No. PFI/BIC 1534054

    NMR Characterizations of the Ice Binding Surface of an Antifreeze Protein

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    Antifreeze protein (AFP) has a unique function of reducing solution freezing temperature to protect organisms from ice damage. However, its functional mechanism is not well understood. An intriguing question concerning AFP function is how the high selectivity for ice ligand is achieved in the presence of free water of much higher concentration which likely imposes a large kinetic barrier for protein-ice recognition. In this study, we explore this question by investigating the property of the ice binding surface of an antifreeze protein using NMR spectroscopy. An investigation of the temperature gradient of amide proton chemical shift and its correlation with chemical shift deviation from random coil was performed for CfAFP-501, a hyperactive insect AFP. A good correlation between the two parameters was observed for one of the two Thr rows on the ice binding surface. A significant temperature-dependent protein-solvent interaction is found to be the most probable origin for this correlation, which is consistent with a scenario of hydrophobic hydration on the ice binding surface. In accordance with this finding, rotational correlation time analyses combined with relaxation dispersion measurements reveals a weak dimer formation through ice binding surface at room temperature and a population shift of dimer to monomer at low temperature, suggesting hydrophobic effect involved in dimer formation and hence hydrophobic hydration on the ice binding surface of the protein. Our finding of hydrophobic hydration on the ice binding surface provides a test for existing simulation studies. The occurrence of hydrophobic hydration on the ice binding surface is likely unnecessary for enhancing protein-ice binding affinity which is achieved by a tight H-bonding network. Subsequently, we speculate that the hydrophobic hydration occurring on the ice binding surface plays a role in facilitating protein-ice recognition by lowering the kinetic barrier as suggested by some simulation studies
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