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The reduction of Cr(VI) by biosynthesis iron sulfides (FeS1+x) under anoxic conditions has been studied extensively. However, the role of sulfate-reducing bacteria (SRB) when FeS1+x containing SRB removes contaminants during in situ remediation still needs further study. The secondary kinetic constant of biosynthetic FeS1+x with the presence of SRB (called BS-FeS1+x) was 1.72 times that of FeS1+x with the absence of SRB (called BNS-FeS1+x) under FeS1+x:Cr(VI) molar ratio = 10:1, indicating that SRB had a promoting effect on the removal of Cr(VI). Additionally, XPS showed that 5.7% of Cr(VI) remained in the solid phase in the BS-FeS1+x system, indicating BS-FeS1+x could not only remove Cr(VI) by reduction but also by adsorption. Meanwhile, the Cr(VI) removal efficiency of BS-FeS1+x was 100% under anoxic conditions with FeS1+x:Cr(VI) molar ratio = 1:1, which was higher than BNS-SRB (93.4%). SRB could enhance the Cr(VI) removal efficiency, which was possibly due to the constant release of S(-II) and the improvement of the stability and dispersion and the buffering effect. This discovery provided an inspiring idea of the application of biosynthetic iron sulfides to in situ remediation.

Magnetic localization technique has the advantages of millimeter-level localization accuracy, fast localization speed, and no limit-of-sight constraints. However, most studies are limited to the tracking of single or two magnets because of the low localization success rate for multiple magnets, thereby restricting its application scenarios. In this study, a novel multi-magnetic target localization method, named individual memory-based whale optimization and Levenberg-Marquardt (IMWO-LM) algorithm, is proposed to overcome the problem of low localization success rate. The IMWO algorithm adds the individual historical optimal location memory to each whale, which improves the global search ability of the population. This IMWO algorithm result is employed as the initial guess of the LM method. Afterward, the LM result is adopted as the initial guess of the LM method in the subsequent localization process. In 20 groups of 500 localizations, the average localization success rates of the particle swarm optimization-LM algorithm, whale optimization-LM algorithm, and the proposed IMWO-LM algorithm were 85.1%, 83.82%, and 98.28%, respectively. In the experiment of locating three magnetic targets simultaneously, the average position error and the average orientation error were 3.46 mm and 6.77°, respectively. Results show that this method can significantly improve the localization success rate while maintaining high localization accuracy.

Complexes formed by organic matter and clay minerals, which are active components of soil systems, play an important role in the migration and transformation of pollutants in nature. In this study, humic-acid-montmorillonite (HA-MT) and humic-acid-kaolin (HA-KL) complexes were prepared, and their structures before and after the adsorption of aniline were analyzed. The aniline adsorption-desorption characteristics of complexes with different clay minerals and varying HA contents were explored using the static adsorption-desorption equilibrium method. Compared with the pristine clay minerals, the flaky and porous structure of the complexes and the aromaticity were enhanced. The adsorption of aniline on the different clay mineral complexes was nonlinear, and the adsorption capacity increased with increasing HA content. Additionally, the adsorption capacity of HA-MT was higher than that of HA-KL. After adsorption, the specific surface area of the complexes decreased, the surfaces became more complicated, and the aromaticity decreased because aniline is primarily adsorption onto the complexes via aromatic rings. Aniline was adsorbed onto the complexes via spontaneous exothermic physical adsorption. The amount of aniline desorbed from the complexes increased with increasing HA content, and a lag in desorption was observed, with a greater lag for HA-KL than for HA-MT.

A numerical model is developed for surface crack propagation in brittle ceramic coatings, aiming at the intrinsic failure of rare-earth silicate environmental barrier coating systems (EBCs) under combustion conditions in advanced gas turbines. The main features of progressive degradation of EBCs in such conditions are captured, including selective silica vaporization in the top coat due to exposure to water vapor, diffusion path-dependent bond coat oxidation, as well as crack propagation during cyclic thermal loading. In light of these features, user-defined subroutines are implemented in finite element analysis, where surface crack growth is simulated by node separation. Numerical results are validated by existing experimental data, in terms of monosilicate layer thickening, thermal oxide growth, and fracture behaviors. The experimentally observed quasi-linear oxidation in the early stage is also elucidated. Furthermore, it is suggested that surface crack undergoes rapid propagation in the late stage of extended thermal cycling in water vapor and leads to catastrophic failure, driven by both thermal mismatch and oxide growth stresses. The latter is identified as the dominant mechanism of penetration. Based on detailed analyses of failure mechanisms, the optimization strategy of EBCs composition is proposed, balancing the trade-off between mechanical compliance and erosion resistance.

By analyzing an unprecedentedly large, longitudinal HIV-1 CRF07_BC sequence dataset collected from China in the past two decades, we sought to build CRF07_BC lengthwise transmission networks, and understand its transmission dynamics. We divided CRF07_BC into two clusters based on phylogenetic analysis and an estimation of the pairwise genetic distance at 0.7%. Of 6213 sequences, 3607 (58.1%) linked to ≥1 other sequence. CRF07_BC was divided into two clusters: 07BC_O and 07BC_N. The 07BC_O is the original CRF07_BC, circulating in people who inject drugs (PWID) and heterosexuals, predominantly in southwestern and northwestern provinces of China. The 07BC_N is a new cluster, identified mostly in men having sex with men (MSM) in the northern provinces of China. Bayesian analysis indicates that CRF07_BC has experienced two phases of exponential growth, which was first driven by 07BC_O then 07BC_N. Compared to 07BC_O, the proportion of the parameter of population transmission risk (TR) of 07BC_N has risen constantly. The power-law function analyses reveal that 07BC_N has increased over years with higher degree. In 07BC_N, only 13.16% of MSM were linked to other risk groups, but these links represent 41.45%, 54.25%, and 55.07% of links among heterosexual females, heterosexual males, and male PWID respectively. This study indicates that CRF07_BC has evolved into two clusters in China, and their distributions are distinct across risk groups and geographical regions. 07BC_N shows a greater risk of transmission, and has gradually replaced 07BC_O. Furthermore, the results show that strengthening the MSM interventions could lower the rapidity of 07BC_N transmission in all risk groups.

During lung cancer radiotherapy, tumor motion caused by respiration and heartbeat significantly affects radiotherapy efficacy. The real-time and high-precision tracking of the lung tumor during the radiotherapy process remains a big challenge, as the traditional tracking methods have disadvantages such as slow tracking speed, radiation issue, or tracking, and radiotherapy cannot be carried out at the same time. In this study, a magnetic tracking technique based on three permanent magnets was used to localize the tumor in real-time. Thus, precise lung cancer radiotherapy is achieved by adjusting the acceleration position through the magnetic tracking results. Technical verification shows that the tracked centroid accuracies of the simulated tumor based on both one- and three-dipole models were 1.38 ± 0.83 mm, where the tracked tumor diameter accuracy based on the three-dipole model was 1.51 ± 1.30 mm. The phantom experiment indicates that the centroid tracking accuracies of the simulated tumor based on both one- and three-dipole models were 0.36 ± 0.16 and 2.54 ± 1.02 mm, respectively, where the tumor diameter accuracy based on the three-dipole model was 2.15 ± 0.78 mm. Hence, this permanent-magnet-based tumor tracking technique can effectively improve the performance of robotic radiotherapy. Besides, the radiotherapy object can be further expanded from lung cancer to other cancers such as prostate cancer.

Solar-driven water evaporation is a method to make seawater sustainable by producing lower levels of greenhouse gases at present. Herein, we prepared an efficient, flexible and lightweight reduced graphene oxide (rGO)/ polyacrylonitrile (PAN) composite membrane by a simple electrospinning technology for photothermal desalination. After blending with rGO, the electrospun membrane exhibited a strong light absorption property in a wide spectral pectrum and can absorb more than 80% of the light. More importantly, the prepared rGO/PAN membrane presented advantages of good heat localization and high evaporation efficiency. When placed on a thermal barrier made by polystyrene foam, it converts 89.4% of the light into heat, allowing 1.46 kg m−2 of seawater to evaporate in an hour under one sun. Meanwhile, the rGO/PAN membrane was used as a steam generator to obtain the pure water with low ion concentration (Na+: 0.61 mg L−1, Mg2+: 0.67 mg L−1, K+: 1.71 mg L−1, and Ca2+: 0.48 mg L−1) from high salinity simulating seawater. Based on the results, the rGO/PAN membrane provides a new avenue for large-scale photothermal application in the field of seawater desalination.

Magnetic tracking approach (MTA) is mainly based on the observation of the magnetic field produced by a magnetic tracking target. A permanent magnet is usually employed as the tracking target, and a magnetic dipole model is used to estimate the magnetic field. In this article, we introduce an intuitive method to solve the magnetic tracking problem based on graph optimization. A graph is constructed to formulate the tracking problem, whose nodes correspond to the poses of the permanent magnet at different times and whose edges represent constraints derived by sensor measurements. The accuracy and robustness of MTA play a vital role in biomedical and industrial applications. However, a potential abnormal edge will appear in the graph when a magnetic sensor is disturbed by an interference source like a small magnet, which will deteriorate the localization accuracy of MTA. To improve its robustness, Huber cost function is used to reduce the weight of the abnormal edge. Finally, experiments were carried out to verify the performance of the proposed approach with and without magnetic field interference. Comparing the localization errors with the MTA based on the standard Levenberg–Marquardt algorithm, the results illustrate that the proposed approach could achieve superior localization accuracy and anti-interference ability.

Advanced gas turbines pursue efficiency improvement by employing high-temperature lightweight materials. Ceramic matrix composites are the most promising candidates for hot section components. However, they generally require environmental protections for long-term stability in harsh working conditions subjected to water vapor volatilization, accelerated oxidation, severe corrosion and erosion. To this end, environmental barrier coating systems (EBCs) have substantially progressed as an integral design element in the past two decades. As a versatile numerical method, finite element analysis has been widely applied in the investigations of EBCs from stress modeling to service life prediction. This article reviews recent advances in the numerical studies of EBCs for gas turbines, covering fundamental analyses of stress state and heat transfer, elucidations of fracture and damage mechanisms, as well as applications in service conditions. Current numerical solutions, understandings and potential directions are discussed respectively, with general remarks on technical development in the end.

Background Human immunodeficiency virus type 1 (HIV-1) clades and clusters have different epidemic patterns and phenotypic profiles. It is unclear if they also affect patients’ immune recovery (IR) in combination antiretroviral therapy (cART). Methods We conducted a cohort study on 853 patients under cART for evaluating the impacts of viral factor on host IR. We used generalized estimating equations for factors affecting CD4 recovery, Kaplan-Meier curves for probability of achieving IR, and Cox hazards model for factors influencing IR capability. Results Besides low baseline CD4 and old age, CRF01_AE and its cluster 4 were independently associated with lower CD4 cell level (P ≤ .003), slower IR (P ≤ .022), fewer patients (P < .001), and longer time achieving IR (P < .001), compared with CRF07_BC and CRF01_AE cluster 5. Higher percentage of CXCR4 (X4) viruses in the CRF01_AE and cluster 4–infected patients, compared with their respective counterparts (P < .001), accounted for the poor IR in infected patients (P < .001). Finally, we revealed that greater X4 receptor binding propensity of amino acids was exhibited in CRF01_AE clade (P < .001) and its cluster 4 (P ≤ .004). Conclusions Our study demonstrates that the CRF01_AE clade and cluster are associated with poor IR in patients under cART, which is ascribed to a high proportion of viruses with X4 tropism. HIV-1 genotyping and phenotyping should be used as a surveillance tool for patients initiating cART. CCR5 inhibitors should be used with caution in regions with high prevalence of X4 viruses.

In this study, we report a novel HIV-1 second-generation recombinant form composed of CRF01_AE and subtype B detected from a married HIV-positive male subject infected through homosexual behavior in Tianjin in northern China. The near full-length genome analyses showed that two regions of subtype B inserted into the CRF01_AE backbone with four recombinant breakpoints observed in the pol gene region. Subregion tree analyses demonstrated that the CRF01_AE regions of the recombinant were greatly clustered with the CRF01_AE subcluster 4 lineage, which was found primarily among men who have sex with men (MSM) in northern China. To the best of our knowledge, this is the first detection of a novel HIV-1 second-generation recombinant form (CRF01AE/B) in Tianjin, which indicates active transmission networks of HIV-1 infection among MSM in this region. The emergence of the novel second-generation recombinant form highlights the increasing complexity of HIV-1 epidemic among MSM population and the importance to monitor potential novel circulating recombinant forms.

Background: The role of TLR9 expressed by tumor cells in evading immune surveillance was confirmed. PD-L1 expression in tumor cells plays a key role in tumor immune escape, which is associated with poor prognosis. However, the clinical relevance of TLR9 and PD-L1 expression in angioimmunoblastic T-cell lymphoma (AITL) has not been evaluated. Materials and methods: In this study, we identified differentially expressed genes in AITL samples by bioinformatic analysis, and we first examined TLR9 and PD-L1 expression by immunohistochemical staining in patients with AITL and compared these data with clinical features and survival time. Results: It was found that the expression of PD-L1 and multiple TLRs was higher in AITL than normal T-cell samples, and TLR9 and PD-L1 expression displayed complex interactions by bioinformatic analysis. The rates of TLR9 and PD-L1 high expression were 69% and 50%, respectively. High expression of either TLR9 or PD-L1 indicated a poor survival rate for patients with AITL. Multivariate analysis further confirmed that high expression levels of TLR9 and PD-L1 were unfavorable prognostic factors for AITL. We further found inferior overall survival in AITL with clinical features of ECOG status ≥ 2, advanced-stage, elevated serum LDH levels, elevated serum β2-MG levels, and high IPI score. Conclusion: TLR9 and PD-L1 expression may be a novel predictor of prognosis for patients with AITL and may serve as potential therapeutic strategy.

To address the problem that carbon fibre reinforced polymer (CFRP) composite material is not easy to directly measure the bond strength of the CFRP-timber column interface during the process of strengthening timber column, a real-time monitoring method of CFRP-timber interface bond strength based on piezoelectric ceramic active sensing is proposed to determine the interface bond strength directly from the structural response signal. A total of 15 specimens were designed for the active monitoring test and tensile test, and the monitoring signals at different enhancement times were compared and analysed using wavelet packets, power spectral density, and short-time Fourier transform, and it was found that the amplitude and power spectral density of the signals increased as the reinforcement time increased. The mapping relationship between wavelet packet energy and bond strength is obtained, providing a more efficient and robust way of monitoring the bond strength between CFRP and timber columns during reinforcement.

Solar desalination is recognized as one of the eco-friendly and sustainable ways to alleviate the global freshwater crisis but still requires further research, especially in developing high-performance evaporators. Herein, we prepared an efficient carbon nanotubes (CNTs)@polyvinyl alcohol (PVA) nanofibrous hydrogel evaporator by electrospinning and subsequently chemical cross-linking treatment. Due to CNTs with good light absorption capacity, the evaporator exhibited an excellent light absorption capacity (90%) throughout the full spectrum range (250-2500 nm). Meanwhile, the interconnected pores from electrospinning, as well as the intermediate water in the hydrogel, ensured the prepared evaporator with a favorable evaporation rate of up to 2.16 kg m

We report in this study a novel HIV-1 second-generation recombinant form (TJIH0172) composed of CRF01_AE and CRF07_BC isolated from a married HIV-positive male subject infected through homosexual behavior in Tianjin, China. The phylogenetic analysis of the near full-length genome of TJIH0172 reveals that one region of CRF07_BC inserted into the CRF01_AE backbone with two recombinant breakpoints observed in the vpu and env gene regions, respectively. The CRF01_AE regions (the regions I and III) of the recombinant are greatly clustered with the CRF01_AE subcluster 4 lineage, which is mainly circulating among men who have sex with men (MSM) in northern China. The CRF07_BC region (II) is clustered with two sequences (JX960600 and KF250366), which were discovered in the MSM population in Liaoning Province and Beijing city in northern China, respectively. The emergence of the novel recombinant strain from a married man who has sex with men in Tianjin, China, highlights the increasing complexity of the HIV-1 epidemic between MSM and their female partners and further molecular epidemiological investigation should be taken to track married MSM and their female partners to prevent HIV transmit from HIV high-risk populations to general populations.

We have investigated and compared the influence of annealing temperature on composition and interfacial properties of AlN thin films deposited on 4H-SiC substrates by atomic layer deposition using trimethylaluminum (TMA) and ammonia as precursors at 400 °C. Those as-deposited films were annealed by rapid thermal annealing at 700 °C, 800 °C, 900 °C and 1000 °C for 1 min in N2 atmosphere, respectively. As the annealing temperature increased, the thickness of AlN films decreased and the refractive index increased due to the densification and compositional changes in the films. The roughness of films decreased as the films became denser after annealing. In addition, the deposited AlN film is not amorphous structure and the intensity of the (0002) diffraction of the AlN films enhanced in the annealed films. N-O-Al bond broke down and the intensity of Al-N bond increased with the increase of annealing temperature. Moreover, the interface between AlN and SiC was mainly a transition layer containing Al-O-Si, and the intensity of Al-O-Si was enhanced after annealing at 1000 °C. And the annealing process reduced the negative charge and the density of interface trap of the AlN annealed film in the MIS capacitor. These results provide a significant reference for AlN as a gate dielectric for SiC-based MOS devices in the future.

The transit consolidation problem considers simultaneous loading and unloading of cargo to/from containers, is an extension of capacitated vehicle routing problem. For the small batches of cargo with multiple origins and destinations, they need to be transported to the assembly point, where they are sorted and packaged again, and then re-loaded together with the local source of goods according to different destinations or different customers. The increasing importance of multimodal transportation makes it necessary to consider the efficiency of the whole process. The transit consolidation problem is also NP-hard as a capacitated vehicle routing problem and this study proposes a model to quantify the process of transit consolidation, and uses a genetic algorithm to solve this problem. Moreover, the sensitivity of the relevant parameters of the model are analysed by a case study; the average dynamic tonnage utilization ratio improves by comparing with establishing the hub, which proves the feasibility and effectiveness of the method.

The magnetic tracking system, which is based on a permanent magnet and a magnetometer array, has numerous potential applications in the biomedical and industrial area. However, its tracking accuracy drops off sharply with the increase of tracking distance because of both the interference of environmental magnetic field and sensor measurement noise. To extend the magnetic tracking range, two novel methods were proposed in this study. First, the state-of-the-art tri-axial tunnel magnetoresistance (TMR) sensors, which possess the most significant field sensitivity and signal-to-noise ratio (SNR) over other types of magnetoresistive sensors, were adopted to construct the sensor array. Second, a fusion approach was proposed for tracking range extending. The particle swarm optimization-Levenberg Marquardt (PSO-LM) method based on the magnetic dipole model was applied in the near field (i.e., near-source zone), and the prior knowledge based back propagation neural network (PKBPNN) was adopted to the far field (i.e., far-source zone). In the transition zone, these two algorithms were fused by using an adaptive sigmoid function. The trained artificial neural network (ANN) model embodied the physical model errors, the sensor installation errors, and the inherent characteristics of adopted magnetometers. Therefore, it has greater tracking performance than singly using the PSO-LM in the far-source zone. The experimental results show that the tracking errors decrease from (18.24 ± 9.37mm, 12.45 ± 3.37°) to (8.95 ± 1.74mm, 7.97 ± 2.08°) in the tracking range between 216 and 296 mm. Besides, the tracking distance is extended to 396 mm, with the position error of less than 25 mm. It can be concluded that this approach has significantly extended the tracking range of the magnetic tracking system.

Sintering is one of the key issues in the high temperature service of thermal barrier coatings (TBCs), considering the continuously increasing operation temperature of gas-turbine for higher energy efficiency. Based on the conventional processing method of air plasma spraying (APS), suspension plasma spraying (SPS) technique has been developed recently, in order to improve the strain tolerance of TBCs. This strain tolerance of plasma-sprayed TBCs is largely effected by the sintering behavior, which is presently not fully understood. In this work, evolution of mechanical properties, in terms of Young’s modulus and viscosity, is systematically investigated by in-situ three-point bending test at 1200 °C on free-standing coatings, including micro-cracked APS, segmented APS, vertically cracked SPS and columnar structured SPS TBCs and correlated to the microstructural evolution. Based on experimental results, power law relations are proposed for the sintering induced mechanical evolution, which deepen the understanding of the sintering behavior of plasma-sprayed TBCs.

WO3 nanorods were synthesized via a simple hydrothermal approach. Their microstructure and morphology were analyzed with x-ray diffraction, scanning electron microscope and x-ray photoelectron spectroscopy. The effects of reaction temperature, reaction time, and citric acid concentration, on the gas-sensing performance of WO3 nanorods were investigated. The optimized response value of WO3 sensor to ethanol gas (100 ppm) was 26.48, with a response time of 1 s under a low operating temperature (160 °C). The recovery capability and stability of the gas sensor were tested and discussed. Additionally, the working principle of WO3 sensor was proposed. In comparison to the sensors published by previous researchers, the WO3 sensor has shown great potential.

Premature failure of thermal barrier coatings (TBCs) under a temperature gradient is an overriding concern in many applications, and their mechanical parameters are essential to failure analysis. In this study, an in situ micro-indentation apparatus, including a heating module, cooling module, and micro-indentation module, was developed to study the mechanical parameters of TBCs with a temperature gradient. The upper surface of the TBC was heated by radiation to simulate high-temperature service conditions, and the bottom surface was gas-cooled. Different temperature gradients are obtained by changing the velocity of the cooling gas. The temperatures through the thickness of the TBCs were analyzed by numerical simulations and experiments. During exposure to the temperature gradient, micro-indentation tests of the TBC samples were conducted to obtain their mechanical parameters. In situ micro-indentation tests at different cooling gas flow rates (0, 20, and 40 l/min) were performed on the TBCs. The elastic modulus and stress evolution of the TBCs were extracted by analyzing the load–displacement curves at different gas velocities. The elastic modulus remains almost constant with increasing velocity while the stress difference increases.

For 13.56 MHz large-area capacitively coupled plasma (CCP) discharges, the increase of plasma enhanced chemical vapor deposition (PECVD) chamber radius to 500 mm is likely to exacerbate the impact of edge effect. In this paper, based on COMSOL Multiphysics, a two-dimensional fluid model combined with the full set of Maxwell's equations is developed and validated. Simulation results indicate that the existence of the edge effect destroys the radial plasma uniformity of large-area discharges. The decrease of the RF voltage amplitude or chamber pressure causes an improvement in plasma radial uniformity, but the plasma density reduces. Only by adjusting the process parameters, the optimization of plasma uniformity degree is not obvious and the edge effect cannot be eliminated. Furthermore, the chamber structure has a significant influence on plasma uniformity. And enlarging the electrode gap or extending the grounded electrode length could help to obtain a uniform deposition by impairing the edge effect. The experiment results show that the film uniformity is improved by optimizing. The results obtained in this work could play a useful role in weakening the edge effect and raising the plasma uniformity of large-area CCP discharge.

The effect of Ca2+ and alginate on the stability of CeO2 nanoparticles (NPs) was investigated using dynamic light scattering (DLS) and nanoparticle tracking analysis (NTA); the two methods were then compared. DLS showed rapid aggregation of CeO2 NPs in 8 mM Ca2+ solution; however, NTA showed that some primary aggregates (200–400 nm) still remained—a result that was obscured in DLS measurements. Aggregation of alginate molecules was also studied using DLS and NTA, where NTA particle concentration and video provided additional information on the alginate aggregation progress. Finally, DLS showed that in the presence of alginate, the aggregation rate and size of CeO2 NPs increased. NTA intensity measurements provided insight into a heteroaggregation and bridging mechanism. NTA particle concentration and video also showed CeO2 NPs were linked by alginate gel in high Ca2+ concentration (>4 mM). the DLS and NTA had different advantages in measuring particle size. DLS could better study the initial aggregation stage and large aggregates, while NTA could better detect small aggregates. NTA also measured particle number concentration, individual intensity, and particle motion video, which provided additional insight. Combining these two methods could help us to better understand the behavior and fate of NPs in water.

With the accelerated application of copper oxide (CuO) and zinc oxide (ZnO) nanoparticles (NPs) in commercial products, concerns about the potential impacts on the environment have been growing. Environmental behaviors of NPs are expected to significantly influence their fate and ecological risk in the aquatic environment. In this study, the environmental behaviors of two metallic NPs (CuO and ZnO NPs), including aggregation, sedimentation, and dissolution, were systematically evaluated in five representative waters (pool water, lake water, rainwater, tap water, and wastewater) with varying properties. Remarkable aggregation, sedimentation, and dissolution were observed for both metallic NPs, among which ZnO NPs exhibited greater influence. CuO (ZnO) NPs aggregated to 400 (500) nm, 500 (900) nm, and 800 (1500) nm in lake water, wastewater, and tap water, respectively. The sedimentation rates of CuO and ZnO NPs in the five waters were ranked as tap water > wastewater > lake water > pool water > rainwater. The dissolution of CuO and ZnO NPs in waters follows a first-order reaction rate model and is affected by ionic type, ionic strength (IS), and NOM (natural organic matter) concentrations. Redundancy analysis (RDA) indicated that the aggregation and sedimentation of NPs have a strong correlation, insofar as the sedimentation rates increase with increasing aggregation rates. The aggregation and dissolution of NPs have a negative correlation, insofar as the dissolution rates reduce with increasing aggregation rates. The aggregation, sedimentation, and dissolution of NPs can be influenced by ionic types, IS, and TOC in waters, among which, TOC may the dominant factor.

Sintering is one of the major failure mechanisms of air-plasma-sprayed thermal barrier coating system (APS TBCs) during high temperature service. For better sintering resistance, the TBCs with compositional gradient has been developed and fabricated by using advanced feedstocks, e.g. rare earth element-doped and nanostructured powders. Herein, a structurally graded design is put forward to counteract the effect of sintering in a convenient and economic way. Sintering induced degradations, in terms of Young’s modulus and thermal conductivity, are slower in graded porous TBCs, indicated by thermo-mechanical finite element analyses and verified by experiments. Furthermore, a new sintering resistance parameter is proposed to evaluate the sintering resistance of TBCs under experimental (isothermal) and service (thermally graded) conditions. It is shown that graded porous TBCs, with decreasing porosity from top to bottom, exhibits improved sintering resistance and overall performance for engineering application.