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Phytoremediation has been proven to be an alternative in-situ treatment technique for sulfonamide polluted wastewater. However, the fate of sulfonamides in the phytoremediation process of multiple sulfonamides coexistence is unclear. Therefore, the possibility and mechanism of phytoremediation of ten sulfonamides by different wetland plants through hydroponics were investigated in this study. The phytoremediation rates of Σsulfonamides by different wetland plants were from 44.5% to 56.9%. Mass balance analysis showed that rhizosphere biodegradation (90.2% - 92.2%) dominated the phytoremediation of Σsulfonamides, while hydrolysis (7.63% - 8.95%) and plant uptake (0.05% - 0.17%) accounted for a small proportion. It is worth mentioning that the dissipation of the target sulfonamides in the hydroponic system followed the first-order reaction kinetic model, with half-lives of 13.3 d to 53.3 d, which are close to or even lower than that of aerobic biodegradation in river water, sediment, and piggery wastewater. Six of the ten spiked sulfonamides were detected in plant samples demonstrated that the selective uptake of plants under the coexistence of multiple sulfonamides. The distribution of sulfonamides (concentrations and uptake amounts) in plant tissues followed the sequence of rootstemleaf in this study, but the distribution in stems and leaves needs further study. The uptake and rhizosphere biodegradation of Cyperus papyrus to sulfonamides are optimally resulting that its phytoremediation rate is significantly higher than other plants (p0.05), which indicates that plant species is one of the key factors affecting the phytoremediation efficiency of sulfonamides. These findings verify the feasibility of phytoremediation of sulfonamides, and provide new insights into the fate of sulfonamides in the process of phytoremediation.

Research on decentralized wastewaters deserves special focus due to the potential abundance of emerging organic pollutants including pharmaceutical and personal care products (PPCPs), which might pose serious threats to the local water bodies and even to human health. Constructed wetland (CW) is a common decentralized wastewater treatment technology, with a certain ability to eliminate PPCPs. Nonetheless, PPCPs removal in common CWs is frequently challenging, besides, the removal mechanism remains elusive. Based on our previous study, tidal flow constructed wetlands (TFCWs) is effective in nitrogen removal. Here, 3 TFCWs with different modifications (baffle, plants, both baffle and plants) were constructed to treat raw domestic sewage and specifically to evaluate the removal efficiencies and mechanism of PPCPs. 24 PPCPs including 7 antibiotics, 8 steroid hormones and 9 biocides were detected in the level of 1.10 ± 0.29 ng/L-799 ± 10.6 ng/L in the influents. Consequently, we found that modification with both baffle and plants significantly influenced the removal of PPCPs. Moreover, the highest removal rates of biocides (97.1 ± 0.29%), steroid hormones (99.8 ± 0.02%), and antibiotics (90.2 ± 1.60%) were achieved via both baffles and plants in TFCWs. Based on the mass balance analysis, microbial degradation dominated the removal of PPCPs with a percentage higher than 85.7%, followed by substrate adsorption (5.22 × 10−2–14.3%) and plant uptake (1.66 × 10−3–0.44%). Further, 16S rDNA sequencing analysis revealed that the presence of baffle and plants improve the removal efficiency of PPCPs by means of enhancing microbial diversity and changing dominant microorganisms. Moreover, Thaumarchaeota was potentially the key microorganism in the phylum level for PPCPs elimination by TFCWs through LEfSe (linear discriminant analysis (LDA) effect size) analysis. These findings provide new insights into the removal of PPCPs in CWs.

Phytoremediation has proven to be an effective in-situ treatment technique for antibiotic contamination. Due to the immature methods of extracting multi-antibiotics in different plant tissues, the antibiotic absorption and transportation mechanism in the phytoremediation process has yet to be resolved. Therefore, an improved Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) pretreatment with ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) detection method for 28 antibiotics in different plant tissues (root, stem, leaf and seed) was developed in this study. The optimized method showed satisfactory performance with recoveries for most antibiotics ranging from 70% to 130% (except sulfadoxine with 138 ± 8.84% in root, sulfameter with 68.9 ± 1.87% and sulfadoxine with 141 ± 10.0% in seed). The limits of detection (LODs) of the target compounds in root, stem, leaf and seed were 0.04 ± 0.02 ~ 2.50 ± 1.14 ng/g, 0.05 ± 0.02 ~ 1.78 ± 0.42 ng/g, 0.06 ± 0.01 ~ 2.50 ± 0.14 ng/g and 0.13 ± 0.10 ~ 3.64 ± 0.74 ng/g, respectively. This developed method was successfully applied to the determination of antibiotics in different tissues of hydroponic wetland plants exposed to antibiotics-spiked water for one-month. Sixteen of 28 spiked antibiotics were detected in plant tissue samples. Overall, of these 16 antibiotics, all were detected in root samples (from LOQ to 1478 ± 353 ng/g), eleven in stem samples (from LOQ to 425 ± 47.0 ng/g), and nine in leaf samples (from LOQ to 429 ± 84.5 ng/g). This developed analytical method provided a robust tool for the simultaneous screening and determination of antibiotics in different plant tissues.

This paper presents the experimental results and analyses of the friction and local pressure loss coefficient of a 5 × 5 rod bundle with spacer grid. Based on the experimental data, friction and local pressure loss models were assessed and the role of spacer grid was discussed. The results showed that Cheng and Todreas model could predict bare rod friction loss well, and Chun model applied for high Re but would severely underestimate grid local loss for small Re. For two-phase condition, a universal correlation was proposed for bare rod two-phase friction multiplier, and it was found that all existing models cannot predict grid local loss multiplier very well. High prediction accuracy could be obtained by combining homogenous flow model, the liquid-mixture density ratio and a modification factor as a function of the grid parameter e (axial projected area of grid strip to flow area) and void fraction.

In order to simulate the transfer of mass, momentum and energy in the gas-liquid two-phase flow system, tremendous work focused on the phenomenon, mechanisms and models for two-phase flow in different channels, such as circular pipe, rectangular channel, rod bundle and annulus. Drift-flux model is one of the widely used models for its simplicity and good accuracy, especially for the reactor safety analysis codes (RELAP5 and TRAC et al.) and sub-channel analysis code (COBRA, SILFEED and NASCA et al.). Most of the adopted drift-flux models in these codes were developed based on the void fraction measured in pipe and annulus, which were different with the actual nuclear reactor. Although some drift-flux models were developed for rod bundles, they were based on the void fraction on the whole cross-section not in subchannel in rod bundles due to the lack of effective measuring methods. A novel sub-channel impedance void meter (SCIVM) has been developed to measure the void fraction in sub-channel of 5 × 5 rod bundles, which is adopted to evaluate these existing drift-flux models for rod bundles. By comparison, the values of drift-flux parameters have large differences among different correlations, which are suggested to be reconsidered. Based on the experimental data and physical laws, Lellouche-Zolotar and Chexal-Lellouche correlations show a better performance for drift velocity. If the predicting error of void fraction is the only concerned parameter, Chen-Liu, Ishizuka-Inoue and Chexal-Lellouche correlations are recommended for averaged relative error less than 30%. More experiments are suggested to focus on the distribution parameter and drift velocity through their definition.

Traditionally, the flow regime in two phase flow in rod bundles are considered in a global sense by the visualization. However, a sub-channel flow regime is required to understand and model the two phase flow structures in rod bundles. In this work, a sub-channel impedance meter was designed to get the dynamic feature in the sub-channels, which was applied to identify the sub-channel flow regime by the fast search and finding peaks of the cumulative probability distribution functions (CPDFs) objectively. In the present study, five flow regimes, namely bubbly flow, quasi-cap bubbly flow, quasi-slug flow, cap-turbulent flow and churn-turbulent flow were defined and recognized. The sub-channel flow regimes at the same cross section were compared to each other, which show similar feature with the local flow regimes in pipe. It is possible to identify nine different global flow regime configurations by combining the corner, side and inner sub-channel flow regime at the same cross section, which was drawn in the 2D sub-channel flow regime.

In relation to development of the flow regime criteria for rod bundles, this paper provides an experimental flow regime map and compares the experimental map with the existing flow regime transition criteria for vertical rod bundles so far. An experiment of vertical adiabatic air-water flow was conducted under an atmosphere pressure conditions. The experiment facility was composed of 5×5 rod arranged on a square pitch in a square shell with 9.5 mm outside diameter and 12.6 mm pitch. A total of 242 data sets were acquired consisting of superficial gas flow rates, 0.02–8.69 m/s, and superficial liquid flow rates, 0.02–2.13 m/s. A new flow regime map was obtained and the flow regime transition model for rod bundles was validated by the measured flow regime map. A fairly good agreement with some discrepancies has been obtained between the existing flow regime transition criteria and measured flow regime maps for rod bundles.

We present the first experimental investigation of modulational instability in a layered Kerr medium. The particularly interesting and appealing feature of our configuration, consisting of alternating glass-air layers, is the piecewise-constant nature of the material properties, which allows a theoretical linear stability analysis leading to a Kronig-Penney equation whose forbidden bands correspond to the modulationally unstable regimes. We find very good quantitative agreement between theoretical, numerical, and experimental diagnostics of the modulational instability. Because of the periodicity in the evolution variable arising from the layered medium, there are multiple instability regions rather than just one as in a uniform medium.

Surface roughness and grain morphology are among the critical parameters to be monitored during IC wafer processing, because, with the shrinking device critical dimensions, such parameters become more influential in device performance and manufacturing yield. Among the surface roughness and morphology characterization tools, AFM (atomic force microscope) is unmatched in its combination of height profiling sensitivity and lateral resolution. However, the major problem with AFM is fast tip wear, the effects of which are greatest for thin films deposited in front‐end processing because of the minute surface feature sizes and high lateral resolution required for their imaging. To overcome this drawback, the major factors (tip oscillation amplitude and frequency) that influence the performance of AFM operated in the popular tapping mode were studied. The understanding of the effects of these factors allowed us to device a robust method to operate the AFM in a stable attractive tip‐to‐sample interaction regime and to ensure long time life and < 5 nm lateral resolution. This method was applied to the characterization of starting Si substrate, the influence of cleaning parameters on Si substrate and the effect of gate‐oxide thickness. The method was also used for the imaging of the morphology of polysilicon grains which showed strong dependence on the CVD processing parameters.