Coagulation of Colloidal Particles With Ferrate(Vi)

Coagulation and chemical oxidation have long been recognized as two major mechanisms of ferrate(vi) (i.e. FeO42-, an oxyanion containing Fe(vi)) in its environmental applications. Although ferrate(vi) oxidation of various contaminants has been extensively studied, few efforts were made to appreciate the mechanisms and behaviors of ferrate(vi)-driven coagulation in water. In this study, coagulation of colloidal kaolin particles with ferrate(vi) in simulated natural water was investigated under the conditions related to drinking water treatment (initial turbidity 25.00 NTU, 0.0-9.0 mg L-1 Fe(vi), pH 7.5, and 0.50-10.00 mg L-1 DOC). Fe(iii) produced from Fe(vi) reduction initiated in situ coagulation. Lower minimum effective iron doses (MEIDs) were observed for Fe(vi) coagulation than for direct Fe(iii) coagulation at pH 6.5 and 7.5 (DOC = 2.00 mg L-1), at which the colloids were captured by iron precipitates principally via sweep coagulation. A citrate-ascorbate iron extraction method was used to reveal that Fe(vi) resultant flocs were composed of both amorphous and crystalline iron with an amorphous to crystalline Fe ratio of approximately 2.3-:1.0 (pH 7.5, 3.0 mg L-1 Fe(vi), and 2.00 mg L-1 DOC). Ferrate(vi) oxidation transformed natural organic matter (NOM) preferentially into more hydrophilic compounds, which have lower affinity with colloids and thus are less adsorbed on colloids to produce a less negatively charged surface. Therefore, ferrate(vi) oxidation potentially promoted the aggregation of colloids through the alleviation of electrostatic repulsion. However, NOM at a high concentration (8.00-10.00 mg L-1 DOC in this study) could prevent the agglomeration of small iron oxide particles through the formation of a negatively charged NOM coating via adsorption, thereby preventing the growth of flocs. Ferrate(vi) coagulation, when combined with ferrate(vi) oxidation, provides a more viable treatment option to address multiple water pollution in raw water, e.g. the presence of colloidal algal cells and dissolved algal toxins in water during a harmful algal bloom. The dual treatment mechanisms enable a very effective treatment design with an economical physical footprint for supporting a sustainable municipal drinking water supply

Load Transfer Path Search and Its Evaluation between Networks in Consideration of the Mobile Energy Storage of Electric Vehicles

Load transfer is an important way of restoring a power supply after equipment failure or maintenance. However, current methods ignore cooperation between networks and users, and they also fail to take into account the vehicle-to-grid (V2G) potential of electric vehicles (EVs). In this paper, a load transfer scheme between transmission and distribution networks is proposed, considering the mobile energy storage capacities of electric vehicles. First, the mobility characteristic and the available discharge capacity of EVs are analyzed on the basis of the parking generation rate. Then, the breadth-first algorithm is used to search the load transfer paths within and between stations, and an edge matching method is proposed to realize the conversion between networks with different voltage levels. Lastly, the optimal combination weighting method was adopted to combine subjective and objective index weights and to evaluate power supply paths. The effectiveness of the proposed scheme is validated in a case composed of an IEEE 30-node network and an IEEE 57-node network, with four typical scenarios

Fringe projection profilometry method with high efficiency, precision, and convenience:theoretical analysis and development

Fringe projector profilometry (FPP) is an important three-dimensional (3D) measurement technique, especially when high precision and speed are required. Thus, theoretical interrogation is critical to provide deep understanding and possible improvement of FPP. By dividing an FPP measurement process into four steps (system calibration, phase measurement, pixel correspondence, and 3D reconstruction), we give theoretical analysis on the entire process except for the extensively studied calibration step. Our study indeed reveals a series of important system properties, to the best of our knowledge, for the first time: (i) in phase measurement, the optimal and worst fringe angles are proven perpendicular and parallel to epipolar line, respectively, and can be considered as system parameters and can be directly made available during traditional calibration, highlighting the significance of the epipolar line; (ii) in correspondence, when two sets of fringes with different fringe orientations are projected, the highest correspondence precision can be achieved with arbitrary orientations as long as these two orientations are perpendicular to each other; (iii) in reconstruction, a higher reconstruction precision is given by the 4-equation methods, while we notice that the 3-equation methods are almost dominatingly used in literature. Based on these theoretical results, we propose a novel FPP measurement method which (i) only projects one set of fringes with optimal fringe angle to explicitly work together with the epipolar line for precise pixel correspondence; (ii) for the first time, the optimal fringe angle is determined directly from the calibration parameters, instead of being measured; (iii) uses 4 equations for precise 3D reconstruction but we can remove one equation which is equivalent to an epipolar line, making it the first algorithm that can use 3-equation solution to achieve 4-equation precision. Our method is efficient (only one set of fringe patterns is required in projection and the speed is doubled in reconstruction), precise (in both pixel correspondence and 3D reconstruction), and convenient (the computable optimal fringe angle and a closed-form 3-equation solution). We also believe that our work is insightful in revealing fundamental FPP properties, provides a more reasonable measurement for practice, and thus is beneficial to further FPP studies.Ministry of Education (MOE)Published versionFunding: Ministry of Education - Singapore (MOE-T2EP20220-0008); Youth Innovation Promotion Association of the Chinese Academy of Sciences (2019221); National Natural Science Foundation of China (11903036, 1803037, 61805243, 62127901); Bureau of International Cooperation, Chinese Academy of Sciences (181722KYSB20180015); Key Research Program of Frontier Science, Chinese Academy of Sciences (QYZDJ-SSW-JSC038)

Identifying Submarine Engineering Geologic Hazards in a Potential Gas Hydrate Target Area on the Southern Continental Margin of the South China Sea

The southern continental margin-slope area of the South China Sea is a complex passive continental margin with diverse tectonic structures and movements. This area is rich in gas hydrate resources and is also an area with a high incidence of potential geological hazards. Identifying and understanding the potential submarine geological hazards in this area is very important for disaster prevention and management during the future exploration and development of marine resources. In this paper, five types of potentially hazardous geological bodies are identified in the research area through high-precision two-dimensional seismic processing and interpretation, including submarine mounds, pockmarks, mass transport deposits, submarine collapses and faults. At the same time, the seismic reflection characteristics and the changes in its morphology and surrounding strata are described. In addition to the causes of geological hazards in this region and their influence on exploration and development, the research prospects of geological hazards in this region are also suggested. Special tectonic and sedimentary conditions, fluid activities and hydrate decomposition may be the conditions for geological hazards in this region, which pose a significant threat to the exploration and development of seabed resources and marine engineering construction in this region. Not only does our conclusion provide useful data for the development and utilization of gas hydrate, but it also presents theoretical suggestions for reducing geological hazards in the development process

Electrical Properties of Li⁺-Doped Potassium Sodium Niobate Coating Prepared by Supersonic Plasma Spraying

The current work aims to compare the effects of systematic A-site substitutions on the electrical properties of potassium sodium niobate (KNN)-based coating. The A-site elements were replaced by Li+ to form (K0.4675Na0.4675Li0.065) NbO3 (KNLN). The pure KNN coating and the Li+-doped potassium sodium niobate (KNLN) coating with dense morphology and single perovskite structure were successfully prepared by supersonic plasma spraying, and the phase composition, microscopic morphology and electrical properties of the two coatings were compared and analyzed in detail by XRD, XPS, three-dimensional morphology and SEM on an Agilent 4294A (Santa Clara, CA, USA) and FE-5000 wide-range ferroelectric performance tester. The results show that: as the polarization voltage increases, the pure KNN coating is flatter and fuller, but the leakage current is large. The KNLN coating has a relatively long hysteresis loop and is easily polarized. The domain deflection responds faster to the external electric field, and the resistance of the domain wall motion to the external electric field is small. The dielectric constant of KNLN coating is 375, which is much higher than that of the pure KNN coating with 125, and the dielectric loss is stable at 0.01, which is lower than that of pure KNN coating at 0.1–0.35. This is because Li+ doping has successfully constructed a polycrystalline phase boundary in which O-T phases coexist, and has higher dielectric properties, piezoelectric properties and ferroelectric properties. At the same time, due to the high-temperature acceleration process in supersonic plasma spraying, the violent volatilization of the alkaline elements Li+, Na+ and K+ leads to the presence of oxygen vacancies and part of Nb4+ in the coating, which seriously affects the electrical properties of the coating

Electrical Properties of Li+-Doped Potassium Sodium Niobate Coating Prepared by Supersonic Plasma Spraying

The current work aims to compare the effects of systematic A-site substitutions on the electrical properties of potassium sodium niobate (KNN)-based coating. The A-site elements were replaced by Li+ to form (K0.4675Na0.4675Li0.065) NbO3 (KNLN). The pure KNN coating and the Li+-doped potassium sodium niobate (KNLN) coating with dense morphology and single perovskite structure were successfully prepared by supersonic plasma spraying, and the phase composition, microscopic morphology and electrical properties of the two coatings were compared and analyzed in detail by XRD, XPS, three-dimensional morphology and SEM on an Agilent 4294A (Santa Clara, CA, USA) and FE-5000 wide-range ferroelectric performance tester. The results show that: as the polarization voltage increases, the pure KNN coating is flatter and fuller, but the leakage current is large. The KNLN coating has a relatively long hysteresis loop and is easily polarized. The domain deflection responds faster to the external electric field, and the resistance of the domain wall motion to the external electric field is small. The dielectric constant of KNLN coating is 375, which is much higher than that of the pure KNN coating with 125, and the dielectric loss is stable at 0.01, which is lower than that of pure KNN coating at 0.1–0.35. This is because Li+ doping has successfully constructed a polycrystalline phase boundary in which O-T phases coexist, and has higher dielectric properties, piezoelectric properties and ferroelectric properties. At the same time, due to the high-temperature acceleration process in supersonic plasma spraying, the violent volatilization of the alkaline elements Li+, Na+ and K+ leads to the presence of oxygen vacancies and part of Nb4+ in the coating, which seriously affects the electrical properties of the coating

Trimethylamine N-Oxide (TMAO) Inducing Endothelial Injury: UPLC-MS/MS-Based Quantification and the Activation of Cathepsin B-Mediated NLRP3 Inflammasome

TMAO is a new risk biomarker for cardiovascular disease. With trimethylammonium as its main chemical skeleton, TMAO is structurally similar to many endogenous metabolites, such as acetylcholine, carnitine, phosphorylcholine, etc. The mechanism of TMAO on the pathological process of CVD is still unclear. In this study, the quantitative analysis of plasma TMAO is conducted, and the contribution of Cathepsin B and NLRP3 inflammasome during the process of TMAO-induced endothelial injury was proposed and investigated at animal and cellular levels. Immunofluorescence assay was applied to represent the protein expression of Cathepsin B and NLRP3 inflammasome located at endothelial cells. The results showed that TMAO could disrupt endothelial cells permeability to induce endothelial injury, meanwhile, TMAO could increase NLRP3 inflammasome activation and promote the activity and expression of Cathepsin B in vitro and in vivo, whereas inhibition of NLRP3 inflammasome activation by MCC950 could protect the endothelial cells from TMAO associated endothelial injury via Cathepsin B. The study reveals that TMAO can cause endothelial injury via Cathepsin B-dependent NLRP3 inflammasome, and inhibition of Cathepsin B and NLRP3 inflammasome can reduce the TMAO-induced damage. The results provide new insight into the role of TMAO in CVD, which can be a potential therapeutic target for disease treatment and drug design

Study of the Mechanical Properties and Thermal Control Performance of Plasma-Sprayed Alumina Coating on Aluminum Alloy Surface

Thermal control coating is an important means of ensuring that a spacecraft remains operational at high temperatures. Due to limitations regarding preparation technology and material properties, the mechanical properties of the conventional thermal control coatings still need to be improved. To solve this problem, nanostructured alumina coatings (NCs) and conventional alumina coatings (CCs) were prepared using plasma-spraying technology. The microscopic morphology, phase structure, hardness, and thermal control properties (solar absorptance (αs) and emissivity (ε)) of the nanostructured alumina coatings were investigated and compared with those of conventional alumina coatings. The results show that the NC has a higher hardness value (1168.8 HV) and that its reflectivity exceeds 75% in the wavelength range of 446–1586 nm, while a high degree of emissivity of 0.863–0.87 is still maintained at 300–393 K. Furthermore, the results show that these highly reflective properties are related to the phase composition and internal micromorphology of the NC, whereby the solar absorption of the coating is reduced due to the increase in the alpha phase content (21.4%), the high porosity (5.21%) and the nanoparticles favoring the internal scattering. All these properties can improve the performance of this CC coating with low solar absorptance (αs) and high emissivity (ε)