Constructing self‐repairing epoxy materials based on transesterification chemistry can be regarded as a potential path for practical industrial applications given on its simplicity and ease of ...processing. However, there is still a challenge to improve the slow bonding exchange process for desired healing performances. Herein, this work reports a simple and effective strategy to prepare high‐biomass‐content self‐repairing epoxy materials by introducing polyester oligomer (PEO) dicarboxylic acid as modifier into epoxidized soybean oil and itaconic acid compounds. The PEO is synthesized from glutaric anhydride and 1,4‐cyclohexanediol, as well possess a unique pentamer molecular structure. It not only endows the epoxy system with improved molecular mobility in virtue of its long‐chain structure, but also increases the number the essential ester groups of transesterification process, thus synergistically promoting bonding exchange rate for expected properties. As a result, the employment of PEO decreases the activation energy from 100 to 70 KJ/mol, as well as presents optimized self‐repairing efficiency in storage modulus and tensile strength tests compared to the control group. It may provide a new and practical way to fabricate high‐effective self‐repairing epoxy system for industrial applications.
Description of preparation of bio‐based epoxy system with desired self‐repairing performance, and the mechanism for improved self‐repairing properties.
Lidar is extensively used in the industry and mass-market. Due to its measurement accuracy and insensitivity to illumination compared to cameras. It is applied onto a broad range of applications, ...like geodetic engineering, self-driving cars or virtual reality. But the 3D Lidar with multibeam is very expensive, and the massive measurements data cannot be fully leveraged on some constrained platforms. The purpose of this paper is to explore the possibility of using cheap 2D Lidar off-the-shelf, to perform complex 3D reconstruction, moreover, the generated 3D map quality is evaluated by our proposed metrics at the end. The 3D map is constructed in two ways, one way in which the scan is performed at known positions with an external rotary axis not parallel to the intrinsic rotary axis of Lidar. The other way, in which the 2D Lidar for mapping and another 2D Lidar for localization are placed on a trolley, the trolley is pushed on the ground arbitrarily. The generated maps by different approaches are converted to octomaps uniformly before the evaluation. The similarity and difference between two maps will be evaluated by the proposed metrics thoroughly. The whole mapping system is composed of several modular components. A 3D bracket was made for assembling of the Lidar with a long range, the driver and the motor together. A cover platform made for the IMU and 2D Lidar with a shorter range but high accuracy. The software is stacked up in different ROS packages.
The Jiangmen Underground Neutrino Observatory is a neutrino experiment that incorporates 20,012 20-inch photomultiplier tubes (PMTs) and 25,600 3-inch PMTs. A dedicated system was designed to protect ...the PMTs from an implosion chain reaction underwater. As a crucial element of the protection system, over 20,000 acrylic covers were manufactured through injection molding, ensuring high dimensional precision, mechanical strength, and transparency. This paper presents the manufacturing technology, mass production process, and performance characteristics of the acrylic covers.
Lidar is extensively used in the industry and mass-market. Due to its measurement accuracy and insensitivity to illumination compared to cameras, It is applied onto a broad range of applications, ...like geodetic engineering, self driving cars or virtual reality. But the 3D Lidar with multi-beam is very expensive, and the massive measurements data can not be fully leveraged on some constrained platforms. The purpose of this paper is to explore the possibility of using cheap 2D Lidar off-the-shelf, to preform complex 3D Reconstruction, moreover, the generated 3D map quality is evaluated by our proposed metrics at the end. The 3D map is constructed in two ways, one way in which the scan is performed at known positions with an external rotary axis at another plane. The other way, in which the 2D Lidar for mapping and another 2D Lidar for localization are placed on a trolley, the trolley is pushed on the ground arbitrarily. The generated maps by different approaches are converted to octomaps uniformly before the evaluation. The similarity and difference between two maps will be evaluated by the proposed metrics thoroughly. The whole mapping system is composed of several modular components. A 3D bracket was made for assembling of the Lidar with a long range, the driver and the motor together. A cover platform made for the IMU and 2D Lidar with a shorter range but high accuracy. The software is stacked up in different ROS packages.
Groundwater contamination by sulfonamides (SAs) has aroused great concern due to their potential risks to ecosystem and public health. In this work, degradation of SAs with different substituents was ...studied via a single oxygen dominated peroxymonosulfate (PMS) activation process. Recoverable hierarchical CuO/MgO nanosheets (NSs) with highly exposure of active sites and open diffusion channels was employed as a PMS activator. The degradation behavior of sulfamethoxazole (SMX), sulfamethazine (SMZ), sulfadiazine (SDZ), sulfamerazine (SMR) and sulfathiazole (STZ) was studied via batch reactions, revealing an efficient heterogeneous oxidation process. In a fixed-bed column of the supported hierarchical CuO/MgO NSs, simultaneous degradation of the five SAs in complicated water matrix was observed with high removal efficiency, long-term stability and strong anti-interference capability toward background constituents of groundwaters. Kinetic experiments and mechanistic study elucidated PMS was activated by CuO and MgO synergically that incorporating with defective-rich MgO induced highly oxidative Cu3+. The activation of PMS over MgO was mediated by surface oxygen vacancies, while thermal feasible redox cycle of Cu3+/Cu2+ responsible for the activation of PMS over defective CuO. This study may help to understand the simultaneous degradation of different SAs in a nonradical oxidation process and provide a feasible technology for in-situ remediation of SAs-contaminated groundwater.
A feasible nonradical oxidation system based on PMS activation by recoverable CuO/MgO nanosheets was built for simultaneously degrading different sulfonamides (e.g., SMX, STZ, SMT,
SDZ and SMR) in groundwater. Defective CuO/MgO activated PMS synergistically to generate single oxygen (1O2) and then selectively degrade SAs with long-term stability. Display omitted
•Simultaneous degradation of different SAs was explored in a fixed-bed column reactor.•A feasible system of CuO/MgO was built for remediating SAs-contaminated groundwater.•The degradation of SAs followed a nonradical oxidation pathway based on 1O2.•CuO and MgO activated PMS synergistically to produce 1O2.
Nascent MnO2 colloids produced during the permanganate oxidation process is highly oxidative and appealing for eliminating emerging organic contaminants (EOCs). However, the nascent MnO2 colloids ...usually shows dense bulked structure, which blocks the availability of active sites and further enhancement of the reactivity. Herein, spherical nascent MnO2 colloids with mesoporous structure were synthesized via redox reactions between colloidal nanospheres of plant polyphenol (e.g., tannic acid) and permanganate. The mesoporous nascent MnO2 colloids shows highly exposure of active sites with abundant bulk-Mn(III) on the surface (16.2 mol%), and thus exhibits outstanding oxidation performance toward the oxidation of phenolic contaminants. Complete removal of bis-phenol A (BPA, 10 mg/L) was obtained with 1.0 mM of mesoporous nascent MnO2 colloids in 40 min at neutral pH. Mechanism study reveals that both Mn(III) and Mn(IV) contribute to the oxidation of BPA. The presence of bulk-Mn(III) on the surface greatly promotes the reactivity of the mesoporous nascent MnO2 colloids, leading to a high kinetic of 0.12 min−1 during the initial 10 min. The nascent mesoporous MnO2 colloids exhibits high selectivity toward electron rich phenolic contaminants and good performance in complicated water matrix, revealing a promising potential for further application. This work provides a distinct case for engineering novel structured nascent MnO2 colloids for efficient elimination of EOCs in water.
The novel mesoporous structure and presence of highly oxidative Mn(III) in the nascent MnO2 colloids enables efficient oxidation of EOCs. Surface Mn(III) contributes significantly to the rapid oxidation of probe contaminant (BPA) in the initial 10 min reaction. Both coupling reactions and mineralization were involved in the degradation of BPA. Display omitted
•Nascent MnO2 colloids with mesoporous structure and surface-Mn(III) was prepared.•The mesoporous structure of nascent MnO2 colloids relieved the aggregation problem.•The mesoporous nascent MnO2 colloids showed good performance toward EOC oxidation.•Surface-Mn(III) contributed significantly to the removal of emerging organic contaminants.
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