The practical implementation of photocatalytic hydrogen generation faces challenges due to the rapid recombination of photogenerated electron-hole pairs. This study reports the synthesis of a WSP/g- ...C3N4 S-scheme heterojunction catalyst featuring exposed hydrogen evolution active W sites, achieved through in-situ P introducing. Remarkably, the WSP/g-C3N4 catalyst exhibits a superior photocatalytic hydrogen evolution rate of 3.92 mmol h−1 g−1, surpassing g-C3N4 and attaining 112 times the performance of pristine C3N4. A series of characterization techniques and Density functional theory (DFT) reveal that WSP/C3N4 possesses the following advantages as a photocatalyst: 1) Under visible light irradiation, the distinctively ordered and well-crystallized structure generates potential differences, facilitates charge transfers, and enhances the hydrogen evolution activity. 2) The coupling between WSP and g-C3N4 interfaces effectively promotes the directional migration of photogenerated electrons. 3) The shallow bound energy level introduced near the conduction band of WSP effectively prolongs the carrier lifetime. These features collectively contribute to the improved performance of photocatalytic hydrogen evolution. These features collectively contribute to the improved performance of photocatalytic hydrogen evolution. This finding suggests new ways to create organic/inorganic heterojunction composite photocatalysts for efficient hydrogen generation.
•WSP and g-C3N4 have S-scheme charge transfer.•Interface engineering establishes a fast electron transmission path.•The performance of WSP/g-C3N4 photocatalytic hydrogen production is significantly improved, and it has high reusability.•The shallow bound energy level introduced near the conduction band of WSP effectively extends the carrier lifetime.
Laser-induced breakdown spectroscopy (LIBS) has been recognized as a significant tool for quantitative analysis of elements with its unique advantages, especially in combination with multivariate ...calibration methods. However, LIBS spectra typically include large amounts of high-dimensional data that affect the predictive accuracy of multivariate calibration based on LIBS. Feature selection, as an important preprocessing step in data mining, can improve the performance of the multivariate calibration model by eliminating the redundant and irrelevant features. In this study, a hybrid feature selection method based on V-WSP-PSO was proposed to improve the accuracy of LIBS analysis. The proposed method combines the advantages of V-WSP based filter method and particle swarm optimization (PSO) based wrapper method. The uncorrelated and redundant features were first eliminated by V-WSP method to form a simplified input subset, and then the retained features were further refined by PSO method to find a small set of features with high predictive accuracy. In order to evaluate the performance of proposed method, LIBS experiments were performed using 28 coal samples, and a nonlinear multivariate calibration method based on kernel extreme learning machine (KELM) was selected to implement the proposed hybrid feature selection method for calorific value determination of coal. Comparing the proposed method with several other feature selection methods shows that the V-WSP-PSO method is best in terms of number of selected features and predictive accuracy. Finally, 114 features were selected from full spectrum (27620 features) by V-WSP-PSO method and the best root mean square error of cross validation (RMSECV) and determination coefficient of cross validation (RCV2) were 0.4013 MJ/kg and 0.9908, root mean square error of prediction (RMSEP) and determination coefficient of prediction (RP2) were 0.3534 MJ/kg and 0.9894. The overall results demonstrate that the V-WSP-PSO method is more efficient to reduce the redundant features, calculation time and improve the model performance, and it is a good alternative for feature selection in multivariate calibration.
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•A hybrid feature selection method based on V-WSP-PSO was proposed.•The V-WSP-PSO method achieves high accuracy that is characteristic to PSO and high efficiency characteristic to V-WSP.•Compared with several other methods, the proposed method is more effective in feature subset size and predictive accuracy.•It is a promising method for feature selection in multivariate calibration.
This paper investigates the hydraulic performance and solute transport processes in waste stabilization ponds (WSPs). A numerical model comprised of Reynolds-averaged Navier–Stokes (RANS) flow ...hydrodynamic model with the standard k − ε turbulence closure coupled with the advection-diffusion solute transport model, is developed in a three-dimensional Cartesian coordinate system. The proposed numerical model is successfully validated against laboratory-scale physical modelling measurements of flow hydrodynamics and solute characteristics across trapezoidal pond geometry. The developed numerical model is adopted to run series of scenario-based simulations to investigate the effects of WSP's geometrical features and implementation of an island retrofitting on the hydraulic performance and treatment efficiency of the WSPs. Fifteen pond configurations with varying side-walls slope and island configurations are simulated. Vertical and horizontal structures of flow hydrodynamics across the pond are investigated. Solute transport processes are studied through determining residence time distribution (RTDs) curves based on numerical tracer simulations. Two deflector island configurations (parallel and rotated) are simulated to investigate their influence on enhancing the hydraulic performance of the WSP. The analysis of the numerical results indicates an overall positive impact of deflector island retrofitting on the hydraulic performance of the WSP. The side-walls slope are shown to play a key role in determining the overall performance of the WSP. For the cases with side-walls slope of 1:1, 0.5:1 and 0:1, the hydraulic efficiency of the WSP was enhanced by adding both parallel and rotated islands. However, for the cases with side-walls slope of 2:1 and 1.5:1, addition of island deflector is shown to have negative impacts on the hydraulic performance of the waste stabilization pond.
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Aiming at the problem that the wind speed data collected by wind farms are affected by many factors and easy to introduce noise information, a wind speed prediction method based on data decomposition ...of improved singular spectrum analysis (ISSA) is proposed. In this paper, the ISSA is used to decompose the wind speed sequence into a series of sub-sequences. Based on the singular spectrum analysis (SSA), the ISSA introduces the singular entropy to judge the noise components of the wind speed series and remove them. Then, the artificial neural network model is used to calculate and compare the prediction results of several data preprocessing decomposition methods using EMD, EEMD, CEEMD, ISSA and the prediction results without data preprocessing. Experimental results show that the proposed method can effectively improve the prediction accuracy of the artificial neural network, and also has higher prediction accuracy than the comparison method, which verifies the effectiveness of the ISSA.
•Macro and micro properties of WSP and WSR were investigated through swelling tests, DMA and SEM.•Storage modulus was used to measure the dynamic mechanical property of WSR and WSP.•Working ...conditions with different applied loads and salted environment were applied.•WSP presents more stable and better waterproof performance under submarine condition.
This paper investigates the waterproofing properties of two water swelling gasket materials, i.e. water-swelling rubber (WSR) and water-swelling polyurethane (WSP). Swelling tests were performed to measure the swelling ratios in both compression and free swelling states. A dynamic mechanical analyzer (DMA) was employed to measure the storage moduli under different compression pressures and in different saline environments. Scanning electron microscope (SEM) was performed to investigate the micro-damage morphology for both WSR and WSP. According to the test results, under the compression load of 1.0 MPa, the maximum axial swelling ratio (Sa) and free swelling ratio (Sw) of WSP was nearly four times and twice that of WSR, and the storage modulus E’ of WSP was three times that of WSR. Also, the micro-cracks of WSP were much less and shallow than those of WSR under the same load condition and saline environments. Thus, the WSP specimen showed better water-proof performance than the WSR specimen under the complex submarine condition.
Vegetation has been used as a means in geotechnical engineering for soil improvement and erosion control. This paper aims to present a state-of-the-art review and future prospective on soil ...improvement and reinforcement with plants, mainly from a perspective of plant mechanical effects. The mechanics of roots and root-soil composite are reviewed with regard to experiments, including root mechanical tests, direct shear tests, pullout tests and triaxial tests. Various factors influencing root reinforcement are characterized and discussed to explain root-soil interactions and related soil strengthening mechanisms. Considering cost and efficiency, extreme climates, and the conflicting mechanisms of plant growth and soil improvement, researchers have introduced nature-based water-soluble polymers (WSPs) into soil improvement to promote vegetation establishment and provide additional binding strength between soil particles. Despite the benefits, existing related researches and concepts are scarce, and there is still a significant knowledge gap in the coupling effect of WSP and plants for soil improvement. The review indicates that the combination of vegetation and WSP has the potential to create “trade-off” and “complementarity” for progressive soil improvement. Finally, new research topics in the field of soil improvement with plants are identified in the review.
Surface sensing is a critical process that promotes the transition to a biofilm lifestyle. Several surface-sensing mechanisms have been described for a range of species, most involving surface ...appendages, such as flagella and pili. Pseudomonas aeruginosa uses the Wsp chemosensory-like signal transduction pathway to sense surfaces and promote biofilm formation. The methyl-accepting chemotaxis protein WspA recognizes an unknown surface-associated signal and initiates a phosphorylation cascade that activates the diguanylate cyclase WspR. We conducted a screen for Wsp-activating compounds and found that chemicals that impact the cell envelope induce Wsp signaling, increase intracellular c-di-GMP levels, and can promote surface attachment. To isolate the Wsp system from other P. aeruginosa surface-sensing systems, we heterologously expressed it in Escherichia coli and found it sufficient for sensing surfaces and the chemicals identified in our screen. Using well-characterized reporters for different E. coli cell envelope stress responses, we then determined that Wsp sensitivity overlapped with multiple E. coli cell envelope stress-response systems. Using mutational and CRISPRi analysis, we found that misfolded proteins in the periplasm appear to be a major stimulus of the Wsp system. Finally, we show that surface attachment appears to have an immediate, observable effect on cell envelope integrity. Collectively, our results provide experimental evidence that cell envelope stress represents an important feature of surface sensing in P. aeruginosa.
The effect of ultrasonic treatment (25 kHz, 400 W, 20 ℃, 20 min) on water-soluble pectin (WSP) content and structure, and degrading enzymes in cell wall of persimmon fruit during storage was studied. ...Results indicated that after storage for 15 d, the firmness of ultrasonic-treated persimmon fruit increased by 22.43 %, and the activity of pectin degrading enzymes PG, PME, and PL decreased by 34.32 %, 8.52 %, and 17.27 % compared with the control, respectively. Additionally, ultrasonic had little effect on the WSP content, but could slightly inhibit the decrease of WSP molecular weight and branched-chain, thus delaying the degradation of WSP. By inhibiting the activity of pectin degrading enzyme, ultrasonic slowed the depolymerization of the WSP structure and maintained the stability of cell wall structure, thus improving the firmness of persimmon fruit. The results will provide a reference for revealing the mechanism of ultrasonic on fruit softening.
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•Ultrasonic treatment could maintain the firmness of persimmon fruit.•Ultrasonic treatment could slightly inhibit the structure decrease of WSP.•Ultrasonic treatment inhibited the increase of the activity of PG, PME and PL.
Waste stabilization pond (WSP) is natural technology which can be installed in centralized or semi-centralized sewerage systems for treatment of domestic and industrial wastewater, septage and ...sludge, etc. WSPs are highly efficient, simple to construct, low cost and easy to operate. It can be used as secondary or tertiary treatment unit in a treatment plant either individually or in a coupling manner. The algal-bacterial symbiosis in WSP makes it completely natural treatment process for which it becomes economic as compared to other treatment technologies in terms of its maintenance cost and energy requirement. Effluent from WSP can also be used for agricultural purpose, gardening, watering road, vehicle wash, etc. Advance technologies are being integrated for better design and efficiency of WSP, but the main challenges are the separation and removal of algal species which lead to deterioration of the water if stays long. Research is necessary to maximize algal growth yield, selection of beneficial strain and optimizing harvesting methods. This review focuses on the treatment mechanism in the pond, affecting factors, types of ponds, design equation, cost analysis.
•Factors considered in Design of Waste Stabilization Pond (WSP).•Various mechanism of pollutants removal in WSP.•Mathematical models available related to pond.•Cost analysis of stabilization pond.
Mosquitoes are vectors of many pathogens, such as malaria, dengue virus, yellow fever virus, filaria and Japanese encephalitis virus. Wolbachia are capable of inducing a wide range of reproductive ...abnormalities in their hosts, such as cytoplasmic incompatibility. Wolbachia has been proposed as a tool to modify mosquitoes that are resistant to pathogen infection as an alternative vector control strategy. This study aimed to determine natural Wolbachia infections in different mosquito species across Hainan Province, China.
Adult mosquitoes were collected using light traps, human landing catches and aspirators in five areas in Hainan Province from May 2020 to November 2021. Species were identified based on morphological characteristics, species-specific PCR and DNA barcoding of cox1 assays. Molecular classification of species and phylogenetic analyses of Wolbachia infections were conducted based on the sequences from PCR products of cox1, wsp, 16S rRNA and FtsZ gene segments.
A total of 413 female adult mosquitoes representing 15 species were identified molecularly and analyzed. Four mosquito species (Aedes albopictus, Culex quinquefasciatus, Armigeres subalbatus and Culex gelidus) were positive for Wolbachia infection. The overall Wolbachia infection rate for all mosquitoes tested in this study was 36.1% but varied among species. Wolbachia types A, B and mixed infections of A × B were detected in Ae. albopictus mosquitoes. A total of five wsp haplotypes, six FtsZ haplotypes and six 16S rRNA haplotypes were detected from Wolbachia infections. Phylogenetic tree analysis of wsp sequences classified them into three groups (type A, B and C) of Wolbachia strains compared to two groups each for FtsZ and 16S rRNA sequences. A novel type C Wolbachia strain was detected in Cx. gelidus by both single locus wsp gene and the combination of three genes.
Our study revealed the prevalence and distribution of Wolbachia in mosquitoes from Hainan Province, China. Knowledge of the prevalence and diversity of Wolbachia strains in local mosquito populations will provide part of the baseline information required for current and future Wolbachia-based vector control approaches to be conducted in Hainan Province.
