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The enhancement of aerodynamic performance of airfoil using Gurney flap was demonstrated and due to its effects of lift increasing and stall suppression on airfoil, Gurney flap has positively functioned in a wide range of engineering. Though there had been numerous scholars who aroused wide concern on geometric parameters of Gurney flap for airfoil, the investigation of geometric design of Gurney flap for straight-bladed vertical axis wind turbine is absent. In current research, a comprehensive numerical study on the effect of geometric parameters of Gurney flap on performance enhancement of straight-bladed vertical axis wind turbine. Before a validation between numerical results and experimental data was carried out, a novel mathematical model of resistance torque of struts was put forward to increase the reliability of numerical model. The results show that the Gurney flap can remarkably promote the aerodynamic performance of vertical axis wind turbine with a decreased rotational velocity. The maximum improvement can reach up to 21.32%. In upstream area, Gurney flap can considerably increase the blade tangential force. Short-Gurney-flap blade can effective weaken the deficiency of aerodynamic loss in downstream area. The 0.75%-chord-length height is most appropriate for the straight-bladed vertical axis wind turbine in this paper. The aerodynamic load with Gurney flap is not sensitive to width. The design with 0.12%-chord-length width is the most suitable value through analyzing the power coefficient curve.

Single-atom catalysts (SACs) have been applied in various fields as they display extremely high utilization efficiency of catalytic sites. A majority of SACs prepared by high-temperature calcination suffer from poor water dispersion and lose of labelling groups. Herein cobalt SACs (CSACs) were synthesized with a solvothermal method by adopting hybridized MOFs Fe

In this study, two dual-anode assembled microbial desalination cells (DA-MDCs) composed of two anodes, one cathode and two membrane stacks were constructed, with a hollow fiber membrane (HFM) module coupling into the cathode to filtrate suspended solids and microbes. Enriched domestic wastewater treatment performance of the DA-MDC system under different hydraulic retention time (HRT) was investigated in detail. When HRT sequentially decreased from 10 h, 8 h, 6 h to 4 h, the conductivity in diluent effluent kept stable at first, but increased 519% at 4 h compared with 6 h. Nevertheless, the chemical oxygen demand, total nitrogen and total phosphorus in the effluent met the wastewater discharge standards in China at all HRTs. Additionally, transmembrane pressure of the HFM modules increased sharply when HRT changed from 6 h to 4 h. Therefore, HRT 6 h was selected as the optimal condition. Under such short HRT, the system realized wastewater treatment capacity of 10 L/d, surpassing all bio-cathode microbial desalination cell systems aiming to realize efficient treatment of domestic wastewater. Additionally, the salt removal rate of 0.215 g/h was more than two times compared with most similar systems. Finally, stratified microbial community structures in the cathodes of the system were found. This gave evidence on the efficient catholyte recirculation which might facilitate nitrogen removal from wastewater.

Adsorption behavior of thiadiazole derivatives, 2,5-bis(ethyldisulfanyl)-1,3,4-thiadiazole (DTA), dimercapto-1,3,4-thiadiazole (DMDT) as anticorrosion additives at copper oxide surface were studied by first-principles calculations, weight loss, electrochemical and surface characterization techniques. The adsorption energies calculated by density functional theory (DFT) were less than 0.3 eV, DTA and DMDT physically adsorbed on the copper surface and cannot replace the oxygen atom at the top site of the Cu O slab models. The predicted physically interaction of the corrosion inhibitor on the copper surface, which was basically consistent with the results of XPS analysis and surface microtopography. It was shown that in the presence of DTA and DMDT adsorbed on copper surface depress the reaction rate of anodic dissolution and cathodic hydrogen evolution and obey Langmuir isotherm. Surface findings indicated the inhibitor film formed at copper surface can block corrosion and improve hydrophobicity.

In this study, nitrobenzene was degraded using ozone/persulfate oxidation process in a rotating packed bed with semi-batch operation. NB degradation efficiencies by only using ozone or persulfate in the oxidation system were at 69.44% and 27.14%, respectively, whereas O3/Na2S2O8 system achieved degradation efficiency at 90.59% in 30 min. It was discovered that degradation efficiency of nitrobenzene was significantly affected by initial pH, high gravity factor, addition amount of persulfate or ozone, and it achieved the highest value when pH at 10, high gravity factor at 40, and initially respective concentrations of extra added persulfate and ozone at 2.5 mmol·L − 1 and 60 mg·L − 1. The production of hydroxyl radicals (·OH) and sulfate radicals (SO4·−) was directly identified in electron paramagnetic resonance tests and indirectly through capturing tests, and three ways of oxidation were determined including direct oxidation by O3, indirect oxidation by ·OH and SO4·−, within which ·OH played a significant role in oxidation process. This study also used gas chromatography-mass spectrometry to detect the intermediates in the oxidation process, and two degradation pathways were inferred based on intermediate analysis.

Solar energy can share with a big percentage in solving in the environmental pollution and energy crisis in China. For the most application of solar energy, an accurate information of solar radiation amount received by a horizontal surface is the first step. In this study, nine-day of the year based models are calibrated and evaluated to estimate the daily global solar radiation (DGSR) on a horizontal surface using long-term data of 84 stations all over China. After dividing China into five solar climatic zones, the highest performance model for each zone is chosen to be a general day of the year based models and then calibrate and evaluated at each solar zone. Based on statistical indicator; the root mean square error (RMSE), the mean absolute bias error (MABE), coefficient of determination (R2) and the correlation coefficient (r) and the uncertainty based on a 95% confidence level (U95) and Taylor diagram, results show that the models perform best in the solar zones that receive a high amount of solar radiation and the performance decreases with decreasing of the daily solar radiation incidence. The hybrid sine and cosine wave day of the year based models exhibit the best performance, model D7 is the best for zone I and model D8 for zones II and IV. For zones II and V, the Gaussian form model (D3 model) and the 4th order polynomial model (D4 model) yield high performance, respectively. Whereas, the two Gaussian form model is the worth performance for all zones. The developed general day of the year based models for each zone in this study can be used with high accuracy to estimate the (DGSR) on a horizontal surface in areas where there is no data or the data is missing all over China.

In this paper, a silicon optical waveguide with high light coupling efficiency and large misalignment tolerance between the silicon waveguide and the laser diode is presented. The silicon optical passive device is designed as a multi-branch structure based upon the silicon on insulator (SOI) platform, which is like a power splitter used in turn. The laser diode is mounted at the end of the multi-branch SOI waveguide structure by flip-chip bonding process. Theoretically, by optimizing the silicon waveguide structure, more than 52% light power of the semiconductor laser diode is coupled into the multi-branch waveguide and a mismatch of 20 μ m in a specific direction only leads to a decrease of 5% in the coupling efficiency. Experimentally, a 37.5% coupling efficiency is obtained from an integrated unit consisting of a single mode laser and the multi-branch waveguide by using a normal precision flip-chip bonder. The special multi-branch waveguide structure is reported for the first time.

The decomposition kinetics of aqueous ozone in a rotating packed bed (RPB) at 18 ± 2 °C and in the pH range 3.0–11.0 was firstly investigated. The decomposition rate of ozone increased with increasing pH value and rotor speed. Moreover, a reaction kinetic model for ozone decomposition in RPB was developed, which can be applied for an extended range of pHs from acidic to alkaline operating conditions. It was deduced that ozone decomposition was based on pseudo-first-order kinetics with respect to the ozone concentration. The degree of the chain reaction between ozone molecule and hydroxyl ion in RPB was found higher than that in batch reactor. Furthermore, experiments showed that NO3−, Cl−, HCO3− and CO32− ions could promote the self-decomposition of ozone to some extent and the promotion effect of CO32− ion was the largest.

Anaerobic osmotic membrane bioreactor (AnOMBR) attracted attention due to high quality effluent production with low energy demand, and draw solute has significant effect on the system performance. However, the mutual relationship between draw solute-induced salinity accumulation and microbial community had many unknown questions to be solved. This study purpose was to construct two AnOMBR to compare the impact of draw solutes of NaCl and MgCl2 on the dynamic change of microbial ecology and membrane fouling. The result indicated that the draw solute of MgCl2 caused less salinity and more membrane biofouling than that of the draw solute NaCl. Multiple microbiological analysis methods were applied to discover keystone species related to the conductivity change and membrane fouling, especially for the MgCl2-AnOMBR system. It was found that draw solute NaCl could benefit the growth of Proteobacteria to become the most abundant phylum to affect the membrane fouling, while Mg2+ introduction could stimulate the growth of NS9, Hydrogenphilaceae and Pedosphaeraceae to potentially cause the biofouling. Furthermore, phylogenetic molecular ecological networks (pMENs) deeply analyzed the microbial structure difference under Na+ and Mg2+ introduction, and indicated that the family Lentimicrobiaceae and Candidatus_Kaiserbacteria were the keystone species in NaCl-AnOMBR, while two genus Anaerolinea and SWB02, and two families Saprospiraceae and NS9 were discovered to have key effect in MgCl2-AnOMBR due to their strong extracellular polymeric substances (EPS) production ability for survival of other microorganisms. This study was significant to give microbial targets under the impact of various draw solutes, as the reference for the engineers to further investigate how to improve the microbial structure to enhance AnOMBR performance and inhibit the membrane biofouling.

Based on the improved effect of synthetic jet (SJ) on airfoil aerodynamic characteristics and the configuration characteristics of dual synthesis jets actuator (DSJ), the effects of DSJ actuators arranged at the trailing edge on the aerodynamic efficiency of straight-blade vertical axis wind turbine (SB-VAWT) were studied. By comparing with the experimental results, the accuracy of the numerical simulation results of clean SB-VAWT power coefficient is verified. In order to consider the control effect of the arrangement, the actuation frequency and the momentum coefficient, the Unsteady Reynolds-Averaged Navier-Stokes (URANS) and the SST k-ω turbulence model were used to simulate the SB-VAWT with different types and parameters. The simulation results show that the three arrangement modes of the trailing edge DSJ actuator proposed in this paper can effectively improve the power capacity of VAWT. Among them, Juxtaposition-type is the best. Through periodic “blowing” and “sucking”, the trailing edge vortex is induced to fall off in advance and delay the occurrence of stall. When λ = 2.05, f = 360 Hz, Cμ = 1.975 × 10−2, the power coefficient can be increased by 58.87%.

Surfactants are often used to elute the contaminants from soils in order to remediate the polluted soils. However, the heterogeneity of minerals and organic matters with soil particle size may result in adsorption and precipitation of surfactants and affect the distribution of petroleum hydrocarbons (PHCs). In this work, spiked soil samples and surfactant mixture consisting of Tween 80 (TW80) and sodium dodecyl sulfate were prepared. Results showed that the silt-clay-mixture held the high retention capacity of PHCs, and 30% total petroleum hydrocarbons (TPHs) was retained in the soil fraction of '125 μm' (high concentration), while 70% TPHs (low concentration) was retained in the soil fraction of '125 μm'. TW80 was highly adsorbed on the montmorillonite and aluminosilicates of the soil, and the adsorption of TW80 in surfactant mixture could be relieved at mass ratio of 1:1. This study provides a novel strategy in the elution removal of PHCs from the contaminated soils, in which with the separation of soil particles by the size of 125 μm before elution, as high as 80% PHCs could be eluted from the soil by surfactant mixture.

The degradation and mineralization of aniline (AN) using ozone combined with Fenton reagent (O3/Fenton) in a rotating packed bed (RPB) was proposed in this study, and the process (RPB-O3/Fenton) was compared with conventional O3/Fenton in a stirred tank reactor (STR-O3/Fenton) or single ozonation in an RPB (RPB-O3). Effects of high gravity factor, H2O2 dosage, H2O2 dosing method and initial pH on the AN mineralization efficiency were investigated in the RPB-O3/Fenton process. In addition, the behavior of Fe(II) was monitored at different H2O2 dosing methods and pH values. Finally, the optimal operation conditions were determined with high gravity factor of 100, initial pH of 5, Fe(II) concentration of 0.8 mmol·L− 1 and H2O2 dosage of 2.5 ml. Under these conditions, for aniline wastewater at the volume of 1 L and concentration of 200 mg·L− 1, a fast and thorough decay of AN was conducted in 10 min, and the TOC removal efficiency reached 89% in 60 min. The main intermediates of p-benzoquinone, nitrobenzene, maleic acid and oxalic acid were identified by liquid chromatography/mass spectroscopy (LC/MS), and the degradation pathways of AN in RPB-O3/Fenton system were proposed based on experimental evidence. It could be envisioned that high-gravity technology combined with O3/Fenton processes would be promising in the rapid and efficient mineralization of wastewater.

A liquid-liquid extraction of nitrobenzene (NB) in impinging stream-rotating packed bed (IS-RPB) was proposed using cyclohexane as an extractant, presented for its improvement of micromixing and mass transfer performance. The effects of pH, phase ratio (the flow rate of organic phase/aqueous phase) and rotating speed of IS-RPB on removal efficiency and extraction stage efficiency of NB were investigated experimentally in IS-RPB. The experimental result showed that the removal rate of NB reached 94.93%, and extraction stage efficiency was 99.99% in IS-RPB, respectively, under the following experimental conditions including: a pH of 6.4, a temperature of 25 °C, a phase ratio of 1:1, a liquid flow rate of 50 L/h, a rotating speed for IS-RPB of 400 r/min, and an initial impinging velocity of 7.88 m/s. Besides, IS, RPB and IS-RPB were compared based on the removal rate of NB and extraction stage efficiency in the same experimental conditions. Compared with other mixing devices, IS-RPB has better extraction stage efficiency and shorter extraction time than other extraction devices, proving that high gravity technology can be utilized to effectively improve the extraction stage efficiency and has a good application prospect.

Liver fibrosis is a persistent pathological repair of chronic liver injury, which is characterized by excessive deposition of collagen-dominated extracellular matrix (ECM). It is well known that hepatic fibrosis can be reversed in the absence of etiology. Studies have shown that long non-coding RNA (Lnc RNA) maternally expressed gene3 (MEG3) has strong effects on the activation of hepatic stellata cells (HSCs). However, the function of MEG3 in the reversal of liver fibrosis has not been studied. In this experiment, we studied the content expression, function, and part of the potential mechanism of MEG3 in reversing liver fibrosis. In in vivo and in vitro models, we found that MEG3 was down-regulated during the formation of liver fibrosis, while it was up-regulated during the reversal of liver fibrosis. Then, it was found that the silencing of MEG3 could gradually restore the activity of the inactivated LX-2 cells, Overexpression of MEG3 can inhibit the activation of LX-2 cells, accelerate the reversal of liver fibrosis. Through catRAPID analysis, it was found that NLR family CARD domain containing 5 (NLRC5) may be a target of MEG3. We found that, after MEG3 silencing, NLRC5 expression was upregulated in LX-2 cells in the reverse phase, while, after MEG3 overexpression, NLRC5 expression was decreased. Further, we verified that MEG3 can target NLRC5 through RNA pull down experiment. Therefore, MEG3 may inhibit the activation of hepatic stellate cells by targeting NLRC5, thus accelerating the reversal of hepatic fibrosis.

Yellow drum (Nibea albiflora), a commercially important fish species in the coastal regions of southeast China, suffers greatly from attacks from bacteria, viruses, and parasites. To uncover their immune responses, the yellow drums were artificially challenged with the pathogenic Vibrio harveyi, and genome-wide association study (GWAS) was performed to identify the associated SNPs and genetic loci for disease resistance trait. Sequence analysis in 197 susceptible and 148 resistant fish identified 23 significantly associated SNPs and 8 candidate genes distributed in chromosome 14. The estimated proportion of phenotypic variance explained (PVE) by SNPs ranged from 10.64% to 13.68%. The discovery of sphingosine kinase (SPHK), CACNA1H, and MGAT5B harboring or within the flanking region of trait-associated SNPs may account for the underlying antibacterial mechanism in yellow drum. These results provide molecular basis for prevention of disease spread and a reference for genetic breeding in fish aquaculture.

Natural organic acids can reduce Cr(VI) to Cr(III) in soil and aquatic environments, but that reductive reaction is too slow for practical application in a Cr(VI) removal process. In this study, we prepared ceramsite particles (CPs) and used them in a citric acid-based Cr(VI) reduction process to analyze their catalytic functions and find their optimal reduction conditions under increasing pH and with and without light. CPs increased the apparent reduction rate constants from 16.35 at pH = 2.6 to 44.85 mg L−1 d−1, and increasing pH decreased the CPs’ catalytic effect. Light positively influenced the reduction rate, which more than doubled under illumination compared to the rate in the dark. We identified soluble Fe(III), that had dissolved from CPs in the reaction solution, as the catalyst for Cr(VI) reduction by citric acid. Under light, soluble Fe(III) complexed with citric acid, and those initiated complexes yielded Fe(II)-citrate and reductive organic radicals that promote Cr(VI) reduction. In the dark, Fe(III)-citrate combined with Cr(VI) to form ring complexes that were responsible for rapid Cr(VI) reduction. Our results reveal how CPs containing soluble Fe(III) can efficiently promote Cr(VI) reduction by organic matter in an aqueous solution.

Biohythane is alternative fuel to replace fossil fuel for car combustion, and biohythane generation could be potential pathway for energy recovery from wastewater treatment. Microbial electrolysis cell (MEC) is electrochemical technique to convert waste to methane and hydrogen gas for biohythane generation, but the feasibility and stability of MEC needs further investigation to assure sustainable energy recovery. System configuration is paramount factor for electrochemical reaction and mass transfer, and this study was to investigate the configuration impact (single vs dual chamber) of MEC for biohythane generation rate and stability. This study showed that dual-chamber MEC could separate methane and hydrogen gas production in the anode and cathode, and combined both together to produce biohythane. To reduce ohmic resistance for higher current, cation exchange membrane (CEM) was removed from dual-chamber to single-chamber MEC. However, free hydrogen diffusion was allowed in the single chamber since CEM was removed. The diffused hydrogen and substrate towards the cathode would favor the methanogen growth, and thus the hydrogen was consumed to reduce the biohythane generation and energy recovery efficiency (i.e., 7.5 × 10−3 reduced to 5.7 × 10−3 kWh kg−1 degraded COD day−1 after converting dual-chamber to single-chamber MEC). Absolute abundance of methanogen in single-chamber MEC was greatly boosted, as Methanosarcina and Methanobacteriale on the anode surface, increased by 132% and 243%, respectively, while the original dual-chamber MEC could maintain Geobacter growth for high current generation. This is the keystone study to demonstrate the importance of dual-chamber MEC for the feasibility and stability for the biohythane generation, building up the foundation to use electrochemical device to convert the organic waste to the alternative biohythane.

To explore the adsorption behaviour of high pressure carbon dioxide (HPCD) in protein, shrimp surimi was made into a cylinder, a radial adsorption prototype was established, and the adsorption mass of HPCD in shrimp surimi was measured using a adsorption instrument with a magnetic suspension balance. The adsorption mass measured directly by the instrument was the excess adsorption mass of CO2 in shrimp surimi and not the actual adsorption mass. The excess adsorption mass was corrected to the absolute adsorption mass. The absolute adsorption mass more accurately represented the CO2 adsorption capacity of shrimp surimi. Under isothermal conditions, the absolute specific adsorption increased and reached a maximum near the critical point (7.38 MPa) of CO2 and gradually decreased and stabilised with the increase in pressure. Under isobaric conditions, the absolute specific adsorption decreased with increasing temperature. Maximal absolute specific adsorption ranged from 46.99 to 99.49 cm3/g at 35–60 °C.

The emulsified behaviors in the process of preparing methanol-diesel emulsified fuel are investigated by the application of an impinging stream-rotating packed bed (IS-RPB). The emulsified processes are composed of the combinations of initial emulsification of impinging stream process, intensified emulsification of IS-RPB and perfect emulsification of back-splashing and atomization to complete the entire emulsified process through the analysis of force posed on all fluid particles in IS-RPB. The existence of the three emulsified processes is proved using the computational fluid dynamics (CFD) simulations. The turbulent kinetic energy and velocity vector of the three emulsified processes using the CFD simulations were analyzed logically, which proved the existence of the three emulsified processes. Based on the analysis and CFD simulations, the properties of stabilization, dispersion, micro-mixing and power consumption performance were compared under the IS-RPB and high speed stirrer, which further prove the practicability and advancement of this technology for methanol-diesel emulsified fuel.

Bioelectrochemical systems (BES) can recover ammonia from wastewater driven by electricity generation. However, energy consumption of such an approach has not been well evaluated. In this study, the effects of several key operating factors including catholyte aeration rate, external voltage, and external resistance on both ammonia recovery and energy consumption were systematically investigated. A mathematical model developed for ammonia removal/recovery in BES was applied to help interpret the experimental results. It was found that a high aeration rate in the catholyte could facilitate ammonia recovery. An aeration rate of 100 mL min −1 resulted in the lowest energy consumption of 4.9 kWh kg −1 N recovery among the tested aeration rates. A low external resistance facilitated the ammonia recovery via higher current generation, while a moderate external voltage (e.g., 0.5 V) helped to achieve low energy consumption. The highest ammonia recovery rate of 7.1 g N m −2 d −1 was obtained with energy consumption of 5.7 kWh kg −1 N recovery. Therefore, there is a trade-off between energy consumption and ammonia recovery.

Biohythane is a renewable energy fuel composed of methane and hydrogen gas at a certain ratio. Microbial electrolysis cells (MECs) have been employed to produce biohythane but the composition of the produced gas is not well controlled. Herein, an innovative MEC system was developed at a large scale of 19 L to investigate biohythane production affected by operational factors. The goal was to understand the interaction between operation and performance towards the development of effective strategies for controlling biohythane composition. To achieve this goal, the performance of this MEC system was studied by varying the key operational factors including anolyte recirculation rate, external resistance, and hydraulic residence time (HRT). It was found that the optimized operational condition for this MEC system included the anolyte recirculation rate of 800 mL min −1 , external resistance of 1 Ω, and HRT of 24 h. This condition led to the biohythane production of 0.64 ± 0.06 L day −1 with 16.5% H 2 proportion and positive net energy recovery of 1.52 ± 0.19 kW h day −1 . The ANOVA test indicated that the anolyte recirculation rate significantly impacted the methane production rate while the external resistance strongly affected the proportion of hydrogen gas in biohythane. HRT had a minor effect on the biohythane composition but could significantly influence organic removal rate. This is the first study that attempted to use operational factors to control biohythane composition, and its results will provide important implications to formulate control strategies for biohythane production and to scale up MEC systems towards practical applications.

Dense-phase carbon dioxide (DPCD) can induce myosin denaturation and aggregation and result in the formation of a gel. To explore the mechanism that DPCD induce myosin the formation of gels, molecular dynamics simulations were used to investigate the effects of DPCD on the structural properties of the myosin heavy chain (MHC, GenBank Accession No: BAM65721.1 ) from Litopenaeus vannamei. In addition, the interaction between the MHC and CO2 was explored under the coupling of pressure and temperature. To facilitate a better understanding and comparison, the structure of MHC was simulated in water at 0.1 MPa and 50 °C (called the myosin-water system, MWS) and in water and DPCD at 25 MPa and 50 °C (called the myosin-water-DPCD system, MWDS). The analysis of the root-mean-square deviation (RMSD) and root-mean-square fluctuation (RMSF) revealed that the conformation of the MHC in both MWDS and MWS changed significantly relative to its initial structure. Moreover, the results of the solvent-accessible surface area demonstrated that the MHC structure changes from a compact arrangement to a looser arrangement in both MWDS and MWS. Finally, the results from investigations into the secondary structures showed that the α-helix content of the MHC decreased, whereas the β-turn and random coil content increased. Greater overall structural variations of the MHC were observed in MWDS than those observed in MWS. DPCD exerts a substantial effect on the MHC structure because of its hydrogen bonding, electrostatic repulsion and hydrophobic interactions with the MHC.

A novel process based on an impinging stream-rotating packed bed (IS-RPB) was proposed for preparing nanoscale zero-valent iron (NZVI) and degrading nitrobenzene (NB) simultaneously. The obtained NZVI particles were characterized by scanning electron microscopy (SEM), high-resolution transmission electron microscopy experiments (HRTEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The experimental results showed that the NB removal efficiency increased with the augment of liquid flow rate and initial reactant concentrations. The NZVI prepared with Fe2+ as an iron source had high reactive activity and its removal efficiency of NB could be maintained at a high level in acidic or a weakly basic condition (pH

Mathematical modeling is an important tool to investigate the performance of microbial fuel cell (MFC) towards its optimized design. To overcome the shortcoming of traditional MFC models, an ensemble model is developed through integrating both engineering model and statistical analytics for the extrapolation scenarios in this study. Such an ensemble model can reduce laboring effort in parameter calibration and require fewer measurement data to achieve comparable accuracy to traditional statistical model under both the normal and extreme operation regions. Based on different weight between current generation and organic removal efficiency, the ensemble model can give recommended input factor settings to achieve the best current generation and organic removal efficiency. The model predicts a set of optimal design factors for the present tubular MFCs including the anode flow rate of 3.47 mL min −1 , organic concentration of 0.71 g L −1 , and catholyte pumping flow rate of 14.74 mL min −1 to achieve the peak current at 39.2 mA. To maintain 100% organic removal efficiency, the anode flow rate and organic concentration should be controlled lower than 1.04 mL min −1 and 0.22 g L −1 , respectively. The developed ensemble model can be potentially modified to model other types of MFCs or bioelectrochemical systems.

Integration of algae and cyanobacteria with microbial fuel cell bioelectrochemical systems (BES) can significantly improve energy recovery and nutrient remediation in wastewater treatment. One innovative option is an integrated photobioelectrochemical system (IPB). Algae can contribute to BES function as an organic feedstock to support bacterial growth, by assisting anode bacteria to generate electricity, by providing oxygen from photosynthesis as a cathode electron acceptor, and by removing N and P from effluent water. However, critical interactions among bacteria-algae communities are poorly understood and practical questions such as light and pH conditions and taxa selection need more research to optimize microbial interactions and promote IPB function. Only a few ‘lab weed’ algal and cyanobacterial taxa have been tried in IPB systems but algae offer additional metabolic flexibility such as mixotrophy, to further process organic carbon, and nutrient hyperaccumulation, which have yet to be examined for potential in wastewater IPB treatment systems. This review aims to serve as a guide for wastewater bioenergy engineers to address challenges in IPB systems, and identifies a need for more collaboration between algal biologists and engineers to optimize algal-microbial community collaboration and work towards improved sustainability of wastewater treatment.

High gravity (Higee) has gained a great attention owing to its advantages of highly efficient mass transfer, energy saving and cost reduction. Higee technology has been studied extensively to improve mass transfer in the treatment of various wastewaters. Understanding the general theory and current status of the Higee-enhanced wastewater treatment will help with advancing this technology towards further development. In this review, the recent status of Higee development, various Higee configurations, working mechanisms of Higee technology in wastewater treatment have been introduced. The integration of Higee with other treatment technologies were described in detail, including coupling Higee with oxidants, electrolysis, advanced oxidation processes (AOPs), stripping, ozonation, electrochemical processes, photocatalytic oxidation, adsorption, or extraction. The effects of operating factors on the Higee coupled treatment systems were discussed with respect to the treatment efficiency, cost and facility. To move Higee technology towards practical applications, there is a need for improving the understanding of fundamental theories, investigation of residence time distribution, and more pilot studies of treating actual wastewater. The Higee-enhanced wastewater treatment can be promising to assist the conventional treatment with saving operational cost and improving treatment performance.

An integrated photo-bioelectrochemical (IPB) system is innovative through integrating microbial fuel cells (MFCs) with algal bioreactors for simultaneous organics degradation, nutrient removal, and bioenergy production. A mathematical model has been developed for simulating and understanding the performance of the IPB system. The model inputs include influent COD (chemical oxygen demand), NH4+-N, total phosphorus, external resistance and flow rate, while the outputs include the biomass growth, COD degradation, nutrient removal, and electricity generation. The determination of unknown model parameters was assisted with sensitivity analysis. Satisfactory model fitting and validation was achieved, with low root-mean-square error of 5.6% and 0.2%, respectively, for biomass concentration and current generation under varied COD input. The simulated results suggested that the organic input and flow rate had more significant impacts on the growth of algal biomass than other input factors, while COD, flow rate and external resistance were of importance for current generation. The optimal condition for improving this particular IPB system was predicted to have a COD concentration above 150 mg L−1 and the flow rate at 0.1 mL min−1. This IPB model is the first attempt of the kind for the optimization of an integrated bioprocess of electrochemical reactions and algal growth.

Efficient oil–water separation plays a vital role in treating large amounts of industrial wastewater. However, current traditional separation methods are entwined with problems such as low efficiency and poor operability. Herein, we reported a nanofiber based on electrospinning and electrospray technology and spraying microspheres on the surface of a fiber mat for efficient oil–water separation. Owing to the electrostatic repulsion among the microspheres, the surface of the developed membrane had a honeycomb-like through-hole structure and super-high oil–water separation efficiency and oil flux. After 10 cycles, the membrane showed good separation efficiency and flux. This innovative work may provide a new idea and method for the design of biomimetic biopolymers, with broad application prospects in the field of oil–water separation.

Forward osmosis (FO) is a promising technology for water treatment, but its fouling mechanisms are poorly understood compared to other membrane-based processes. This study focuses on combined fouling caused by alginate (SA) and TiO2 nanoparticles, which serve as representative organic and inorganic foulants, respectively. The results show that the co-presence of TiO2 can effectively mitigate membrane fouling by SA under vas feed chemistries (Ca2+ concentrations). The negative charge of the SA foulants increased in the presence of TiO2, alleviating SA aggregation due to electrostatic and steric stabilization. The behavior and mechanisms of membrane fouling were characterized by attenuated total reflection-Fourier transformation infrared spectroscopy (ATR-FTIR) coupled with isothermal titration calorimetry (ITC) and atomic force microscopy (AFM) at the molecular level. Combined SA-TiO2 had a lower binding affinity to Ca2+ than single SA, which was spontaneously exothermic and dominated by electrostatic interaction to reduce membrane fouling. This study provides new insight into the mechanisms of nanoparticles-mediated organic fouling in the FO process. It also demonstrates that an integrated ATR-FTIR/ITC/AFM approach can provide useful information for understanding other complicated interactions between inorganic and organic foulants.

Electrode material is a key component in microbial fuel cells (MFCs), and exploring cost-effective electrode materials will greatly help with MFC development, especially the scaling up. In this study, a commercially available material – nickel-coated carbon fiber (Ni-CF) has been investigated as an alternative cathode electrode material to carbon cloth (CC). Both three-electrode cell and MFC tests are carried to examine electrochemical performance and actual electricity generation of the prepared cathode electrodes. It is found that Ni-CF exhibited higher current generation in linear sweep voltammetry (LSV) and lower resistance in electrochemical impedance spectroscopy (EIS) tests than those of CC and CF. When being coated with AC, Ni-CF has the highest actual loading amount among the tested materials. As a result, AC/Ni-CF leads to lower charge transfer resistance (95.1 Ω) and higher current density (8.07 mA m−2) than AC/CC (115.3 Ω and 3.40 mA m−2). In the MFC test, the cathode using AC/Ni-CF results in the maximum power density of 6.50 W m−3, higher than AC/CC at 4.29 W m−3. This high power output gives cost efficiency of AC/Ni-CF at 299.0 mW $−1, nearly twice that of AC/CC (151.7 mW $−1). The initial AC coating amount of 4 g is found to be the optimal amount to achieve optimally actual AC loading amount on the cathode electrode with balanced catalytic ability and (possible) oxygen transfer. Those results encourage further investigation of Ni-CF for MFC applications towards improved performance and cost efficiency.

Detailed investigation was performed on the effect of the rotating stall and surge on the fatigue failure mechanisms of the axial compressor first stage rotor blades. The static stress distribution of the blades was analysed using three dimensional (3D) finite element method (FEM). The critical fracture stress was calculated using the linear elastic fracture mechanics. Fractographic observation revealed different fatigue fracture modes corresponding to the different fatigue loads. Results demonstrated that during operation two kinds of fatigue loads can occur which are tension-torsion fatigue and bending fatigue. The tension-torsion fatigue stems from the periodic tension-torsion stress induced by the surge, while the bending fatigue load is caused by the rotating stall.

We report on ultra-short pulse single-section mode-locked lasers emitting at 1.55 μm, based on self-assembled InAs/InGaAsP/InP quantum dot active regions grown by metal-organic vapor phase epitaxy (MOVPE). For a 1.5-mm-long Fabry-Perot laser, mode-locking at a repetition rate of 29.8 GHz with pulse duration of 855 fs is obtained without any external pulse compression techniques. The mode-beating exhibits a narrow RF linewidth less than 30 kHz, and a wide frequency tuning range up to 73 MHz can be achieved by simply changing the injection current. Moreover, a higher repetition rate of 55.6 GHz and the transform limited Gaussian-pulse with the 707 fs pulse duration are achieved from a device with a shorter cavity length of 0.8 mm.

InAs/InAsSb superlattices were grown on (0 0 1) GaSb substrates by metal organic chemical vapor deposition for potential applications as mid-infrared optoelectronic devices. X-ray diffraction, transmission electron microscopy, photoluminescence emission and spectral photoconductivity were used to characterize the grown structures. Generally, photoluminescence emission measurements of InAs/InAsSb superlattices were performed over the temperature range from 11 K to 300 K. The Varshni and Bose–Einstein parameters were determined. Low-temperature photoluminescence measurements showed peaks at 3–5 μm, while photoconductance results showed strong spectral response up to room temperature, when the photoresponse onset was extended to 5.5 μm. The photoluminescence emission band covers the CO 2 absorption peak making it suitable for application in CO 2 detection.

InAs/InAsSb superlattices were grown on (001) GaSb substrates by metal organic chemical vapor deposition for potential applications as mid-infrared optoelectronic devices. Atomic force microscopy, X-ray diffraction, transmission electron microscopy and photoluminescence emission were used to characterize the grown structures. The photoluminescence emissions from InAs/InAsSb superlattices were performed over the temperature range from 11 K to 300 K. The Varshni and Bose-Einstein parameters determined for energy gap were extracted from the photoluminescence spectra by the fitting procedures. The mid-infrared InAs/InAsSb superlattices showed a temperature change of 0.32 meV/K. The value is smaller than that of HgCdTe and InSb, making them more desirable for high operating temperature infrared devices.

An integrated photo-bioelectrochemical system (IPB) for wastewater treatment combines a microbial fuel cell with an algal bioreactor, eliminating requirements for aeration, promoting electricity generation, remediating nutrients and producing algal biomass for conversion into biofuel or other bioproducts. To examine strategies for improving IPB functions of electrochemical output and nutrient removal efficiency, this study tested effects of cathode bacterial inoculation and nitrogen loading on cathode microbial community and IPB performance. IPB cathodes were inoculated with the green alga Chlorella vulgaris, in combination with nitrite-oxidizing bacteria (NOB) Nitrobacter winogradskyi, and/or ammonium-oxidizing bacteria (AOB) Nitrosomonas europaea. IPB performance was examined before and after nitrifying bacteria inoculations and under three ammonium loading concentrations in the wastewater medium. Bacterial communities in the cathode suspension and biofilm were examined by 16S rRNA gene sequence analysis. Relative to the algae only control, cathode inoculation with NOB and/or AOB improved net nutrient removal, but resulted in reduced dissolved oxygen availability, which impaired electricity generation. Higher ammonium loading increased electricity production and nutrient removal, possibly by overcoming algal-bacterial competition. Inoculation with nitrifying bacteria resulted in minor changes to total bacterial composition and AOB or NOB comprised3% of total sequences after 1 month. Community composition changed more dramatically following increase in ammonium-N concentration from 40 to 80 mg L