DTNF膜对煤化工HERO高盐废水的分盐实验研究

以新疆某煤化工高效反渗透（HERO）高盐废水为研究对象,测试了碟管式纳滤（DTNF）膜在70%、80%、90%回收率下的分盐效果,并择优采用高级氧化进行了纯化处理。中试结果表明,DTNF膜对HERO高盐废水有很好的分盐效果;提质后的氯化钠结晶盐纯度≥98.5%,满足GB/T 5462—2015《工业盐》精制工业干盐一级标准;硫酸钠结晶盐纯度≥98%,满足GB/T 6009—2014《工业无水硫酸钠》Ⅱ类一等品标准。     

ZnIn2S4/In(OH)3 hollow microspheres fabricated by one-step l-cysteine-mediated hydrothermal growth for enhanced hydrogen production and MB degradation

An intervening barrier for photocatalytic water decomposition and pollutant degradation is the frustratingly quick recombination of e⁻ - h⁺ pairs. Delicate design of heterojunction photocatalysts by coupling the semiconductors at nanoscale with well-matched geometrical and electronic alignments is an effective strategy to ameliorate the charge separation. Here a facile and environment-friendly l-cysteine-assisted hydrothermal process under weakly alkaline conditions is demonstrated for the first time to fabricate ZnIn₂S₄/In(OH)₃ hollow microspheres with intimate contact, which are verified by XRD, SEM, (HR)TEM, XPS, N₂ adsorption-desorption, UV–Vis DRS and photoluminescence spectra. ZnIn₂S₄/In(OH)₃ heterostructure (L-cys/Zn²⁺ = 4, molar ratio) with a band-gap of 2.50 eV, demonstrates the best photocatalytic performance for water reduction and MB degradation under visible light, outperforming its counterparts (In(OH)₃ and ZnIn₂S₄). The excellent activity of ZnIn₂S₄/In(OH)₃ heterostructure arises from the intercrossed band-edge positions as well as the unique hollow structure with large surface area and wide pore-size distribution, which are beneficial for the efficient charge migration from bulk to surface as well as at the interface between ZnIn₂S₄ and In(OH)₃. This work provides an efficient and eco-friendly strategy for one-pot synthesis of heterostructured composites with intimate contact for photocatalytic application.     

Identification of Wiener systems based on the variable forgetting factor multierror stochastic gradient and the key term separation

The identification of Wiener systems is very difficult because of the output nonlinearity and the parameter product term. To identify the Wiener system, a novel stochastic gradient algorithm based on the multierror and the key term separation is proposed. Firstly, the Wiener system is parameterized as a pseudo-linear model to avoid the products of the parameters. Secondly, a parzen window is used to estimate the probability density function of the error. Thirdly, a stochastic information gradient algorithm with the multierror is adopted to estimate the parameters. The multierror takes the place of the scalar error by the stacked error, which accelerates the algorithm greatly. Fourthly, a variable forgetting factor considering errors is integrated to further speed the algorithm up. Finally, the proposed algorithm is validated by a numerical example and an industrial case. The estimation results indicate that the proposed algorithm can obtain accurate estimates with fast convergence speed.     

Vocal production in postpartum dairy cows: Temporal organization and association with maternal and stress behaviors

Mammalian vocalizations can encode contextual information in both the spectrographic components of their individual vocal units and in their temporal organization. Here we observed 23 Holstein-Friesian dairy cows immediately after birth during interactions with their calf and when their calf was separated to the other side of a fence line. We investigated whether the vocalizations emitted in these postpartum contexts would vary temporally. We also described the maternal and stress behaviors preceding and following postpartum vocal production using kinematic diagrams and characterized call sequence structure. The kinematic diagrams highlight the disruption of maternal responses caused by calf separation and show that behavioral and vocal patterns varied according to the cows' emotional states and proximity to the calf in both contexts. During calf interactions, cows mainly produced closed-mouth calls simultaneous to licking their calf, whereas an escalation of stress responses was observed during calf separation, with the cows approaching the fence line, becoming alert to the calf, and emitting more mixed and open-mouth calls. Call sequences were similarly structured across contexts, mostly containing repetitions of a single call type, with a mean interval of 0.57 s between calls and a greater cumulative vocalization duration, attributed to an increased number of vocal units per sequence. Overall, calf separation was associated with a greater proportion of calls emitted as a sequence (inverse of single isolated calls), a shorter interval between separate call sequences, and a greater number of vocal units per sequence, compared with calf interactions. These temporal vocal features varied predictably with the high stress expression from cows during calf separation and may represent temporal modulations of emotional expression. Despite the noisy farm soundscape, empirical call type and temporal vocal features were easy to measure; thus, findings could be applied to future cattle studies wishing to analyze vocalizations for on-farm welfare assessments.     

A novel quasi-oppositional harmony search algorithm and fuzzy logic controller for frequency stabilization of an isolated hybrid power system

The intermittent wind power in isolated hybrid distributed generation (IHDG) may cause serious problems associated with frequency (f) and power (P) fluctuation. Energy storage devices such as battery, super capacitor, and superconducting magnetic energy storage (SMES) may be used to reduce these fluctuations associated with f and P. This paper presents a study of IHDG power system for improving both f and P deviation profiles with the help of SMES. The studied IHDG power system is consisted of wind turbine generator and diesel engine generator. Both f and P control problems of the studied power system model are addressed in presence or absence of SMES. Fuzzy logic based proportional–integral–derivative (PID) controller with SMES is used for the purpose of minimization of f and P deviations. The different tunable parameters of the PID controller and those of the SMES are tuned by a novel quasi-oppositional harmony search algorithm. Performance study of the IHDG power system model is carried out under different perturbation conditions. The results demonstrate minimum f and P deviations may be achieved by using the proposed fuzzy logic based PID controller along with SMES.     

某铁矿强磁尾矿反浮选回收试验研究

针对我国西部某铁矿强磁选尾矿进行了反浮选回收铁资源的试验研究, 探讨了pH值、抑制剂可溶性淀粉用量、阳离子捕收剂十二胺用量对浮选指标的影响。结果表明, 在矿浆pH=10、可溶性淀粉用量2 400 g/t、十二胺用量400 g/t条件下进行一粗一精(精选药剂用量减半)闭路反浮选, 可获得铁品位43.88%、回收率50.93%的铁精矿产品。     

Precursor self-derived Cu@TiO2 hybrid Schottky junction for enhanced solar-to-hydrogen evolution

Solar-to-hydrogen production has attracted increasing attention since it possesses great potential in alleviating energy and environmental crises to some extent. The key issue is to develop efficient photocatalysts exhibiting superior hydrogen production capability. In this work, Cu@TiO₂ hybrid (Cu nanoparticles encapsulated in TiO₂) has been successfully prepared by Cu₂O self-template reduction through solvothermal treatment in ethylene glycol-water mixed solvent. When octahedral Cu₂O is involved in the reaction system, the Cu₂O@Ti-precursor octahedral structure is first formed and subsequently the Cu@TiO₂ hybrid is prepared with the reduction of ethylene glycol (EG). The Cu@TiO₂ hybrid derived with different mass of Cu exhibits improved photocatalytic hydrogen production performance compare to pure TiO₂ and P25. Among those photocatalysts, the Cu@TiO₂-10% (the copper content is 10 wt%) shows the highest hydrogen evolution rate of 4336.7 μmol g^?1 h^?1, and it is twice as much as the pure TiO₂ and 1.9 times as much as P25, respectively. Based on the photo/electrochemical results, an efficient photo-generated electron-hole separation contributes to the enhancement of photocatalytic H₂ evolution upon the Cu@TiO₂ hybrid. When replacing octahedral Cu₂O with cubic and truncated octahedrons ones, the Cu@TiO₂ hybrid photocatalysts are also obtained and they also display superior solar-to-hydrogen evolution than pure TiO₂ and P25. It is expected this work could develop an approach to design Cu-encapsulated hybrid photocatalysts for hydrogen generation.     

Exceptional supercapacitive performance of bicontinuous carbon/MnO2 composite electrodes

A new type of porous carbon/MnO₂ composites, having bicontinuous structures, i.e., continuous channels and carbon skeletons, was prepared using a phase separation method, followed by a carbonization procedure and a subsequent redox reaction. In this work, such composite electrodes show a high specific capacitance of ca. 260?F?g^?1 at 0.5?A?g^?1 in 1?M Na₂SO₄ aqueous solution, a superior cycling stability (~80% retention after 2000 cycles) and a distinctive high-rate performance. Especially, unique bicontinuous structures endow such composites with a great specific capacitance of the constituent MnO₂ (~1100?F?g^?1), very close to the theoretical value. These excellent electrochemical behaviors may render this material a promising candidate as high-performance electrodes in supercapacitors. Therefore, our findings suggest that the strategy for constructing bicontinuous hybrid electrodes represents an exciting direction for designing next-generation supercapacitors.     

Extracting Low-Frequency Spatio-Temporal Patterns in Ambient Power System Data Using Blind Source Separation

Wide-area techniques provide a powerful tool to extract spatio-temporal patterns from high-dimensional datasets and can be used for event detection and visualization, data fusion, stability assessment, and coherency analysis. In this paper, a novel blind source separation-based approach for extracting low-frequency spatio-temporal patterns from measured ambient power system data is proposed and a spatio-temporal visualization index is also suggested. This methodology combines a nonlinear hierarchical neural network with a Blind Source Separation (BSS) technique. The neural network allows reducing noise and removing the nonlinear relations among data (preserve dynamic features of interest), while the BSS technique permits extracting spatial and temporal patterns. In addition, the proposed approach takes advantage of the latest techniques in nonlinear estimation of non-stationary time series. Finally, application examples of the proposed framework on real test cases recorded from an actual power system by Phasor Measurement Units (PMUs) are presented. The obtained results show that the temporal patterns can be used for extracting and identifying the low-frequency oscillation modes and the spatial patterns can be used for identifying modes with the most contribution in original data. Compared to other BSS approaches, the proposed method has shown to be better for the analysis of real ambient data.     

Synthesis of High‐Performance Pebax®‐1074/DD3R Mixed‐Matrix Membranes for CO2/CH4 Separation

This work deals with the incorporation of deca‐dodecasil 3 rhombohedral (DD3R) zeolite as an inorganic filler into the Pebax®‐1074‐based polymer matrix to enhance the performance of the pure polymeric membrane in CO₂/CH₄ separation. The membranes were fabricated with different concentrations of DD3R. Separation performances of the membranes were investigated at various feed pressures and temperatures. Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC) analysis of the prepared membranes were performed. In the best case, selectivity for CO₂/CH₄ separation was improved, while the permeability decreased. Membranes with 1 and 5 wt % DD3R were located in the acceptable region beyond the Robeson plot (1991) for CO₂/CH₄ gas pairs.