Image-based measurement of engulfment vortex to quantitatively assess micromixing efficiency in a gas–liquid stirred tank

Micromixing in reactors is typically characterized by chemical test reactions. A novel image-based measurement system of engulfment vortex (IMEV system) is developed to assess the micromixing efficiency. Over 2000 vortices were recognized from images captured under various experimental cases, and key frames for their formation, engulfment and dissipation were identified. Inspired by the engulfment model (i.e., E model), this work quantified the micromixing time and local turbulent energy dissipation rate with the vortex lifetimes. The micromixing time obtained through the IMEV method is comparable to its value estimated by the micromixing model and segregation index of the test reaction, with a deviation of less than 20%. In turbulent gas–liquid systems, bubbles play a dual role on the local micromixing due to frequent disturbance and phase interface limitation. To summarize, this work offers an alternative approach for micromixing studies and provides valuable insights into dispersed phase effects on the micromixing efficiency.     

镓基液态金属柔性应变传感器的设计优化与实验验证

为了描述传感器微通道结构对传感器输出特性的影响，本文引入传感器横纵微通道长度关系的参数横纵比，综合考虑传感器中垂直和平行于应变方向的微通道中液态金属在应变下的电阻变化规律，建立了镓基液态金属柔性应变传感器数学模型。根据建立的数学模型，优化设计并制备了5种应变传感器样品，在40%应变范围内进行实验。结果表明本文建立的数学模型可以良好地预测不同微通道结构传感器的输出，并为设计优化高灵敏度传感器提供了方向。实验测试结果表明设计的应变传感器在40%应变时的灵敏度为2.01、滞后度为5.1%,且重复性和输出稳定性较高。将设计的传感器用于手指、手肘的关节运动检测，探索了镓基液态金属柔性应变传感器在关节运动检测方面的应用。本文为镓基液态金属柔性应变传感器在可穿戴领域中的应用提供了理论支持。     

油气田管道完整性管理效益评估

为了推进油气田管道完整性管理动态效益评估技术的应用，提出了一种基于失效率的管道完整性管理动态效益评估方法，以风险对冲的形式架构完整性管理效益评估顶层框架，以标准应用为目标，划定了效益评估的适用范围，规范了总体实施步骤和操作流程，布置了数据采集方式，解析了效益评估模型和具体算法，最后根据油田目前数据情况在现场开展了该效益评估的简版应用并梳理总结了不足和改进方向。应用发现，为完全实现该完整性管理—金融联动机制，疏通数据渠道是关键，提升底层工程技术是根本。     

干热后处理前后花香型乌龙茶的品质比较

为了研发乌龙茶新产品并提升产品品质，比较分析了干热后处理前后花香型乌龙茶的生化成分和挥发性成分。结果表明：干热后处理后，聚酯型儿茶素A含量显著降低；茶黄素-3''-没食子酸酯、聚酯型儿茶素B和聚酯型儿茶素C含量显著增加；“花香”重要贡献成分二氢芳樟醇的含量在干热后处理前后差异不显著，“蜜香”风味成分2-戊基-呋喃、(E)-2-(2-戊烯基)呋喃、2-乙酰基吡咯增加。基于35种差异挥发性成分的主成分分析表明，干热后处理后，香气类型并未改变，但香气轮廓更清晰。高含量的萜醇类和酯类是的“花香”风味主要赋香成分，2-戊基-呋喃（OAV>1）对形成“蜜香”有重要贡献。综上所述：干热后处理后的乌龙茶产品滋味醇厚，花香浓郁度降低，蜜韵增加。因此，干热后处理有利于新型乌龙茶品质提升，为后续产品研发提供新思路和新方法。     

Photothermal-Enhanced Uranium Extraction from Seawater: A Biomass Solar Thermal Collector with 3D Ion-Transport Networks

Access to uranium resources is critical to the sustainable development of nuclear energy. The ocean contains abundant uranium resources, but the marine biological pollution and the low concentration of uranium make it a giant challenge to extract uranium from seawater. On the foundation of selective uranium adsorption using high uranium-affinity groups, realizing the external-field improved uranium capture without extra energy consumption is highly attractive. A solar thermal collector with 3D ion-transport networks based on environmentally friendly biomass adsorption material is reported, which contains antibacterial adsorption ligands and photothermal graphene oxide. The antibacterial ability through an easy one-step reaction and the fast mass transfer caused by photothermal conversion collaboratively improve the original adsorption capacity of the hydrogel by 46.7%, reaching 9.18 mg g⁻¹ after contact with natural seawater for 14 days. This study provides a universal strategy for the design of physical-fields-enhanced hydrogel adsorbents.     

Basic principle,progress, and prospects of coal gangue ceramic proppants

Ceramic proppants are preferred in hydraulic fracturing because of their high strength, good sphericity, and excellent acid corrosion resistance. Bauxite is the main raw material of ceramic proppants, but with the increasing depletion of bauxite resources, substitutes for bauxite need to be sought. Coal gangue is a solid waste that is rich in SiO₂ and Al₂O₃, making it a potential substitute for the preparation of ceramic proppants. The use of coal gangue to prepare ceramic proppants can reduce the cost of ceramic proppants and benefit environmental protection. Studies on using coal gangue to prepare ceramic proppants have been conducted and achieved progress, but further improvement can still be obtained. Here, the basic principle, progress, and prospects of coal gangue ceramic proppants are reviewed. First, coal gangue ceramic proppants are divided into two categories, namely, proppants prepared using coal gangue as an auxiliary material and proppants prepared using coal gangue as the main material. Second, the progress of research of coal gangue ceramic proppants is summarized from the perspective of additives, and the influence of different kinds of additives on the sintering temperature and performance of proppants is discussed. Lastly, the future prospects of coal gangue ceramic proppants are presented.     

Advances in immunoassay-based strategies for mycotoxin detection in food: From single-mode immunosensors to dual-mode immunosensors

Mycotoxin contamination in foods and other goods has become a broad issue owing to serious toxicity, tremendous threat to public safety, and terrible loss of resources. Herein, it is necessary to develop simple, sensitive, inexpensive, and rapid platforms for the detection of mycotoxins. Currently, the limitation of instrumental and chemical methods cannot be massively applied in practice. Immunoassays are considered one of the best candidates for toxin detection due to their simplicity, rapidness, and cost-effectiveness. Especially, the field of dual-mode immunosensors and corresponding assays is rapidly developing as an advanced and intersected technology. So, this review summarized the types and detection principles of single-mode immunosensors including optical and electrical immunosensors in recent years, then focused on developing dual-mode immunosensors including integrated immunosensors and combined immunosensors to detect mycotoxins, as well as the combination of dual-mode immunosensors with a portable device for point-of-care test. The remaining challenges were discussed with the aim of stimulating future development of dual-mode immunosensors to accelerate the transformation of scientific laboratory technologies into easy-to-operate and rapid detection platforms.     

PEG-based polymer coated proppants in supercritical CO2: A new approach in current fracturing protocols

Liquified carbon dioxide (CO₂) can be used in hydraulic fracturing fluids to provide nonaqueous alternatives to conventional water-based fluids as it is more environmentally benign and minimizing depletion of natural-source freshwater. However, conventional CO₂-based fluids are not sufficiently viscous to suspend proppants that are added to fracturing fluids to hold open subterranean fractures. Because of this reduced ability to suspend proppants, CO₂-based fluids have not found its niche yet as future fracturing fluids. Accordingly, a need exists for nonaqueous hydraulic fracturing fluids that adequately support and suspend proppant particles. The present study presents a green alternative of developing a poly(ethylene glycol) based polymers coated proppants which can swell in supercritical CO₂ so as to decrease the entire density of the proppant during fracturing process.