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Electrocatalytic water oxidation requires efficient catalysts to reduce the overpotential and accelerate the sluggish kinetics of oxygen formation. Here, a promising NiFeBa material was prepared by the co-electrodeposition of Ba2+ , Ni2+ , and Fe3+ as an efficient catalyst for electrocatalytic water oxidation. NiFeBa showed enhanced water oxidation performance compared with NiFe layered double hydroxide and NiFe oxide, delivering a current density of 10 mA cm-2 at an overpotential of 180 mV. Doped Ba ions played a key role in stabilizing the electrogenerated Ni3+ species, producing more octahedral Ni-O structures for lattice oxygen-based water oxidation, adjusting the catalytic mechanism, and finally leading to an enhancement of catalytic efficiency.

A molecular [Ru(bda)]-type (bda = 2,2’-bipyridine-6,6’-dicarboxylate) water oxidation catalyst with 4-vinylpyridine as the axial ligand (Complex 1) was immobilized or co-immobilized with 1-(trifluoromethyl)-4-vinylbenzene (3F) or styrene (St) blocking units on the surface of glassy carbon (GC) electrodes by electrochemical polymerization, in order to prepare the corresponding poly-1@GC, poly-1+P3F@GC, and poly-1+PSt@GC functional electrodes. Kinetic measurements of the electrode surface reaction revealed that [Ru(bda)] triggers the O–O bond formation via (1) the radical coupling interaction between the two metallo-oxyl radicals (I2M) in the homo-coupling polymer (poly-1), and (2) the water nucleophilic attack (WNA) pathway in poly-1+P3F and poly-1+PSt copolymers. The comparison of the three electrodes revealed that the second coordination sphere of the water oxidation catalysts plays vital roles in stabilizing their reaction intermediates, tuning the O–O bond formation pathways and improving the water oxidation reaction kinetics without changing the first coordination structures.

Seawater oxygen evolution is one of the promising energy conversion technologies for large-scale renewable energy storage. It requires efficient catalysts to accelerate the oxygen evolution reactio...

Bismuth vanadate (BiVO4) is one of the most fascinating building blocks for the design and assembly of highly efficient artificial photosynthesis devices for solar water splitting. Our recent report has shown that borate treated BiVO4 (B-BiVO4) results in an improved water oxidation performance. In this study, further improvement of both the photoelectrochemical (PEC) activity and stability of B-BiVO4 was successfully achieved by introducing NiFeV LDHs as an oxygen evolution catalyst and interfacial hole transporter. Benefiting from the synergistic effect of co-catalyst and borate pretreatment, the as-prepared NiFeV/B-BiVO4 exhibited a high photocurrent density of 4.6 mA cm−2 at 1.23 VRHE and an outstanding onset potential of ∼0.2 VRHE with good long-term stability. More importantly, NiFeV was found to play a pivotal role in the critically efficient suppression of charge combination on the BiVO4 surface and acceleration of charge transfer rather than a mere electrocatalyst for water oxidation.

The objective of the study is to recognise whether epoxy resin or polyurethane internal linings of ductile iron (DI) pipes create visibly smaller head loss in flow than cement mortar linings. Some data reported by the Ductile Iron Pipes Research Association (DIPRA) was used in the calculations. Only the data from hydraulic tests performed no later than 30 years after the placing of the mortar lining were considered. The average values of the Hazen–Williams roughness coefficients C for each of the internal pipe diameters were calculated, and single experimental data neglected. Two different approaches were taken for interpreting the DIPRA experimental results and omitting the fact that the flow rates during these tests are unknown. The Hazen–Williams roughness coefficients C were used in both for computing the friction factor f from the Moody chart for three values of flow rate: being equal to the optimal value for a given diameter, and then by 50% larger and 50% smaller than this value. Next, the computed friction factors were compared with the values predicted from the Moody chart for smooth pipes. In the first approach, the friction factors f were computed using the Epanet2 software, and in the second approach, a general equation for calculating f from known C and flow parameters was applied. Both approaches resulted in friction factors f very close to those for smooth pipes for the whole range of Q. In conclusion, more smooth plastic linings of DI pipes do not result in a significantly more visible saving of energy for pumping.

Adverse effects in the measured gamma spectrum caused by radioactive statistical fluctuations, gamma ray scattering, and electronic noise can be reduced by energy spectrum denoising. Wavelet threshold denoising can be used to perform multi-scale and multi-resolution analysis on noisy signals with small root mean square errors and high signal-to-noise ratios. However, in traditional wavelet threshold denoising methods, there are signal oscillations in hard threshold denoising and constant deviations in soft threshold denoising. An improved wavelet threshold calculation method and threshold processing function are proposed in this paper. The improved threshold calculation method takes into account the influence of the number of wavelet decomposition layers and reduces the deviation caused by the inaccuracy of the threshold. The improved threshold processing function can be continuously guided, which solves the discontinuity of the traditional hard threshold function, avoids the constant deviation caused by the traditional soft threshold method. The examples show that the proposed method can accurately denoise and preserves the characteristic signals well in the gamma energy spectrum.

The characteristics of dissolved organic matter (DOM) that formed during the aerobic and anaerobic incubation of drinking water treatment sludge stored at different temperatures (5 °C, 20 °C, 40 °C) for long periods (7, 14, and 21 days) were investigated. Anaerobic incubation at high temperatures with prolonged storage was found to result in higher organic content than aerobic incubation (3.6–6.8 times at 40 °C). The high temperatures caused changes in the DOM fractions, with humic-like substances mainly formed in aerobic incubation and protein-like substances in anaerobic incubation. Results showed that the fluorescence intensity of humic-like and protein-like substances increased by 45% and 22%, respectively, at the end of the anaerobic incubation period. The UV-absorbing DOM constituents in aerobic incubation had lower molecular weights and were more heterogeneous than those in anaerobic incubation.

This research focuses on characterizing the dissolved organic matter found at water treatment plants with closed systems. Recycled water generated as a by-product of water treatment is added to raw water in those systems. The dissolved organic matter in the raw water was found to be higher in summer than in winter, but the water treatment process was able to produce purified water of the similar quality in both seasons. The recycled water contained mostly low molecular weight and protein-like substances, and this composition was different from that of the raw water, which mainly contained humic-like substances. The recycled water did not influence the concentration of humic-like substances or the molecular weight distribution in the influent water.

In precision agriculture, suitable soil moisture and nutrient levels are important for crop production. Therefore, studying the spatial variability in soil moisture and nutrient, and their impact on crop yield is essential. In this study, spatial variability in soil mechanical composition, bulk density, water content and nutrient content in north China along with its impact on crop yield is investigated. Results show that soil mechanical composition and bulk density respectively exhibited moderate and weak spatial variation at the 0–80 cm soil depth. Soil moisture and NH4+-N contents at the 0–80 cm soil depth showed moderate spatial variation, while soil NO3−-N content showed a moderate spatial variation from the seedling stage to the filling stage and a strong spatial variation from the milk-riping stage to the maturing stage. The maximum attainable yield was achieved under the optimum soil moisture, NH4+-N, or NO3−-N contents for the whole growth period and each growth stage. At high soil water condition, both soil NH4+-N and NO3−-N contents were found to be significantly different between the high and low yield areas, while at low soil water condition, only soil NO3−-N content affected the crop yield significantly. At either low or high soil NO3−-N level, soil NH4+-N content in high-producing areas was significantly lower than that in low-producing areas. Excess fertilization was found in the experimental area. This study can provide a scientific basis for developing appropriate crop irrigation and fertilization management practices to obtain high yield.

Developing cost-effective photocathodes that show desirable performance for use in commercial photoelectrochemical water splitting devices remains a fundamental and practical challenge. Sb2Se3 semiconductors satisfy most of the demands expected for an ideal highly efficient photocathode, including favorable cost and optoelectronic properties. Herein, we have demonstrated outstanding photoelectrodes using a noble-metal-free catalyst, namely, a MoSx-decorated low-cost Sb2Se3/In2S3 heterojunction, as the photocathode. This enabled a maximum photocurrent density of up to −27 mA cm−2 (0 V vs. RHE, 100 mW cm−2, AM 1.5G filter) with a remarkable half solar-to-hydrogen conversion efficiency (STH) of 2.6%, obtained via decreasing charge recombination and accelerating charge transfer through morphological optimization of the In2S3 layer.

There is a universal trend toward a data-driven smart grid, which aims to realize two-way communication of energy flow and data flow between various agents across power generation side, transmission&distribution side, electricity retailors and end users. However, the low frequency electrical measurement data accumulated over a long period of time is insignificant for intelligent agents. This paper presents a machine learning method for reconstructing the low frequency electrical measurement data in smart grid. Firstly, the electrical measurement data is converted into electrical images, and then the low frequency electrical measurement data is reconstructed into high frequency electrical measurement data by generative adversarial network to improve the training stability, Wasserstein distance is introduced into the reconstruction mechanism. In addition, by designing the deep residual network based generator, the deep convolutional network based discriminator as well as the perception loss function, the reconstruction accuracy and the high-frequency detail reduction ability are improved. The proposed method is tested on three publicly available datasets and compared with the traditional data reconstruction method, justifying that this method not only can restore high-frequency details with less error, but also can be generalized to different datasets at one location and to datasets at different locations with satisfactory accuracy.

Aiming at the problem of coordinating system economy, security and control performance in secondary frequency regulation of the power grid, a sectional automatic generation control (AGC) dispatch framework is proposed. The dispatch of AGC is classified as three sections with the sectional dispatch method. Besides, a hierarchical multi-agent deep deterministic policy gradient (HMA-DDPG) algorithm is proposed for the framework in this paper. This algorithm, considering economy and security of the system in AGC dispatch, can ensure the control performance of AGC. Furthermore, through simulation, the control effect of the sectional dispatch method and several AGC dispatch methods on the Guangdong province power grid system and the IEEE 39 bus system is compared. The result shows that the best effect can be achieved with the sectional dispatch method.

Mineral flotation processes are controlled by monitoring the grade of the present minerals. The economy of the flotation process can be significantly improved by on-line analysis of minerals in a slurry. However, online and quantitative mineral identification of slurries is challenging. Industrial developers are demanding novel ideas enabling differentiation between minerals with similar elemental contents, such as scheelite and fluorite or gangue minerals, since they have different flotation properties. The primary focus of this research is the measurement of mineral contents from the elemental concentrations acquired by an on-stream slurry analyser based on X-ray fluorescence (XRF) and near-infrared spectroscopy (NIR). In this work, the samples in the test were obtained from a tungsten dressing plant. It is vital to master the mineral grade for controlling the flotation plant. The XRF parameters were optimised by Monte Carlo simulation, and the XRF and NIR data fusion was discussed. A multivariate statistical method called the least squares support vector machine (LS-SVM) was employed to perform the element-to-mineral conversion. The results show that such data integrations enable on-stream and quantitative identification of slurry mineral contents, especially for scheelite, wolframite, fluorite and calcite, which are essential minerals in tungsten ore beneficiation. This technique can lead to many benefits, such as rapid control of concentrate quality, enhanced recovery and savings in money, time, energy and workforce.

In the current electrical load profile analysis, considering the shortage of traditional methods on the typical load profile extraction of single consumers and the load profile feature extraction, this paper proposes an approach based on time series data mining. Firstly, this method reduces the dimension of the load profile of a single consumer based on the Piecewise Aggregate Approximation(PAA), and re-expresses the load profile of the consumer over a period based on the Symbolic Aggregate approXimation(SAX), representing the consumer’s load profile with a symbolic string to extract the typical load profile. Then, combined with the load characteristic indices and time series-based features, the typical load profiles of different consumers are clustered based on the K-means algorithm to analyze the power consumption behaviors. Finally, this paper performs a case analysis with a UCI test data set, and the results show that the proposed approach can excavate typical power consumption behaviors of consumers and improve the electrical load profile analysis efficiency and the clustering quality.

Coking wastewater (CWW) contains high contents of phenols and other toxic and refractory compounds including polycyclic aromatic hydrocarbons (PAHs) with the most carcinogenic benzo[a]pyrene (BaP) among them. The mechanism of PAHs/BaP degradation in activated sludge of CWW treatment with phenol as co-substrate was studied. For characterizing the structure and functions of microbial community associated with BaP degradation with phenol as co-substrate, high-throughput MiSeq sequencing was used to examine the 16S rRNA genes of microbiology, revealing noticeable shifts in CWW activated sludge bacterial populations. Major genera involved in anaerobic degradation were Tissierella_Soehngenia, Diaphorobacter and Geobacter, whereas in aerobic degradation Rhodanobacter, Dyella and Thauera prevailed. BaP degradation with phenol as co-substrate induced bacterial diversification in CWW activated sludge in opposite trends when anaerobic and aerobic conditions were applied. In order to predict the microbial community functional profiling, a bioinformatics software package of phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt) was run to find that some dominant genera enriched in the BaP pathway may own the ability to degrade PAHs/BaP. Further experiments should focus on testing the dominant genera in BaP degradation at different oxygen levels.

The plant bioassay is the most reliable and efficiently used bioassay in genotoxicity biomonitoring of industrial wastes as it confirms the detection of different endpoints such as cytotoxicity, genotoxicity and mutagenicity using Allium cepa, Vicia faba, Tradescantia spp. etc. An array of such methods using living organisms are available to test the level and variation of toxicity caused by polluting factors. Various research studies have monitored the toxicity of industrial effluents/waste and indicated the cytotoxic, genotoxic and mutagenic nature which can pollute the total environment. Chemical tests may be less accurate and less reliable when compared to biological methods for the purpose of toxicity monitoring of natural resources. The present review investigated the genotoxicity of industrial effluents and wastes by using plant based systems. They are also safe to handle and do not require sophisticated instruments thus providing a sustainable monitoring system to growing problem of environmental pollution.

Zircaloy-4 with 200 wppm hydrogen was irradiated with 3 MeV Fe11+ ions and the microstructural evolution of δ-hydride precipitation under ion irradiation was investigated. TEM observation of unirradiated sample shows the needle-like δ-hydride and the orientation relationship between α-Zr matrix and δ-hydride is (0002)α//(1 1 ¯ 1)δ, [2 1 ¯ 1 ¯ 0]α//[011]δ. After ion irradiation, both and -type dislocation loops were observed in α-Zr matrix. Some circular structures with obviously different contrast from the α-Zr matrix were observed in the irradiated Zircaloy-4-200 wppm H samples. The circular structures were identified as δ-hydrides with an fcc structure by indexing the FFT patterns of HRTEM images. There is an orientation relationship of (01 1 ¯ 1 ¯ )α//(200)δ, [01 1 ¯ 2]α//[011]δ between the circular δ-hydride and α-Zr. The formation of circular δ-hydride is related with ion irradiation and the formation process is explained by the hydrogen trapping mechanism.

The transient components in the early weak fault vibration signals of rolling bearings are easily obscured by intense background noise and cannot be detected quickly. Based on the sparse representation principle, an artificial bee colony (ABC) optimization sparsity method of the Laplace wavelet dictionary is proposed to realize the transient characteristic components in the signal extraction. Sparse decomposition with Orthogonal Matching Pursuit (OMP) algorithm is a signal adaptive decomposition algorithm, and it is one of the effective methods for weak feature extraction under strong noise background. Aiming to select and construct an over-complete dictionary for the sparse representation of rolling bearing fault vibration signals, based on the analysis of fault signals' characteristics, an improved Laplace wavelet atomic library was constructed. For solving extensive calculation and low efficiency of the orthogonal matching pursuit algorithm, this paper combines the ABC algorithm's fast operation characteristics to select the improved Laplace wavelet atom that best matches the fault through the inner product operation, thereby improving the calculation efficiency. Experiments show that the method has a proper matching with the early weak fault signals of rolling bearings and can adequately characterize fault information and judge the fault type more accurately.

The heuristic algorithm has been commonly used in solving the shortest path optimization problem. Recently, the ant colony algorithm is a bionic algorithm with decent performance. This paper proposed an improved ant colony algorithm with weighted penalty strategy to shorten path searching distance. Firstly, the grid method is used to transform the target area into a two-dimensional environment model, and the traditional ant colony algorithm is used to plan the path on the grid environment model. Secondly, shortest path obtained by Dijkstra algorithm is compared with that of the ant colony algorithm to validate its effectiveness. Finally, a weighted penalty strategy is proposed and implemented within ant colony algorithm. The advantage of this proposed algorithm enables the ant colony search to set higher priority on those close to the optimal path, and set lower priority on the undesired path. The weighted strategy has been simulated in MATLAB and it is demonstrated the distance of the optimal path is shorten effectively compared to traditional ant colony algorithm.

This paper introduces a new type of deformable aerial robot, which is based on our redesigned vector vehicle, using the new vector vehicle as a single unit for free combination in the air, different combinations will produce different characteristics to meet various requirements. For example, the horizontal combination of vehicle can make the combined robot one more degree of freedom, and through some special combination methods, the combined robot can speed up and increase the degree of freedom. In the further algorithm research on problem for the free combination of multiple vector vehicles in the air, the first issue is to establish the mathematical model of the vector vehicle group after the free splicing in the air, which is obtained through the communication between the magnet contacts on the vehicles. Second, in order to obtain the geometric center of the newly constructed robot, the coordinate system is constructed with the mother machine as the center. Third, we use Newton-Euler equation to model the new combination of robot. The real-time mathematical model of any number and combination of vehicles can be obtained by using this method, which has important applications in the splicing and separation of vehicle.

Stochastic resonance (SR) is a signal processing method that uses noise to enhance the energy of weak signals. This feature makes it show great potential application value in various fields. Moreover, the memory effect on the past state in time also allows SR to achieve better application and development in the fractional order system. Currently, most of the solutions to fractional SR systems use block diagram simulation methods which are based on the Simulink environment. The simulation solution method solves the system model by putting the fractional calculus into the complex frequency domain, but the complicated calculation and low efficiency make it unable to be conveniently applied to engineering practice. Therefore, this paper proposes a numerical solution method based on predictive correction approach for this problem, and the effectiveness of the proposed method is verified through simulation experiments.

In the study of trajectory tracking of the quadrotor UAV, there exists two major problems: external interference and tracking estimation error. Based on the extended state observer (ESO), a unilateral no-overshoot fast convergence model with Novel Prescribed Performance Control (NPPC) mechanism is proposed in this paper. Firstly, the quadrotor UAV is transformed into an external loop position and an inner loop attitude control system. A novel error transform function is proposed for the limitation that the former prescribed performance control scheme cannot achieve rapid convergence of the system state. Secondly, the controllers are designed by the position subsystem and the attitude subsystem, according to the backstepping method and the ESO are designed to estimate external interference. Finally, it is combined with dynamic surface control to realize the trajectory tracking of the UAV under the external interference. Several simulations based on this proposed model have been performed and the results show that the designed controllers can make the quadrotor from any initial state reach the steady one according to the specified convergence time and have better convergence than Traditional Prescribed Performance Control (TPPC).

In the X-Ray fluorescence (XRF) analysis, valid characteristic peaks of elements are often superimposed on low-frequency backgrounds, which harm the qualitative and quantitative analysis of elements. Therefore, background deduction is an essential part of spectral pre-processing. To address the above issue, this paper proposes a new method for background deduction which combines iterative adaptive window-based wavelet transform (IAWWT) with iterative Gaussian convolution filtering (IGCF). To verify the validity of the proposed algorithm in this paper, XRF spectra of 59 soil standards are obtained. Firstly, background deduction is performed on the spectra by using IDWT, IAWWT, IGCF, and the method proposed in this paper. Secondly, the peak areas of Cr, Mn, and Cu in the spectra are linearly fitted to the true contents of the samples. The results show that the proposed method can effectively deduct the background, and the goodness of fit ( R2 ) of Cr, Mn, and Cu is better than the other three methods after background deduction. Among them, R2 of Cr increases to 0.99, R2 of Mn increases to 0.96, and R2 of Cu increases to 0.97.

For an ideal pulse pileup situation, this paper establishes a triangle-trapezoid dual-channel shaping algorithm by analyzing the correlation between trapezoid and triangle shaping results. In this model, the effective pulses in many pulse pileup situations are preserved, which greatly improves the count rate of the pulse spectra. In this paper, the pulse acquisition process is modeled in MATLAB. The input of the model is the negative exponential decay pulses obtained by discrete direct sampling of the actual spectra, and the effectiveness of the optimization algorithm is verified by inputting different levels of pulse pileup signals. The results show that the improved triangle-trapezoid dual-channel shaping algorithm can more accurately retain the effective pulse values under pulse pileup, improve the count rate of the spectra, and ultimately improve the resolution of the pulse spectra.

Drinking water treatment sludge (DWTS) is a waste by-product from water treatment plants where aluminum and iron salts are the most commonly used coagulants. DWTS was reused to investigate the effects of DWTS on the digestion liquid quality and microorganism activity of excess activated sludge (EAS). DWTS with four suspended solid (SS) concentrations (0%, 2%, 5% and 10%) was added to EAS which was sampled during aerobic and anaerobic digestion processes, then batch tests were carried out which followed the coagulation-flocculation process. It was found that DWTS can improve total dissolved nitrogen (TDN) and dissolved phosphorus (DP) removal efficiencies for anaerobic EAS. The highest removal efficiency of TDN (29.97%) as well as DP (55.38%) was observed when DWTS dosage was SS = 10%. The release of dissolved organic matter (DOM) by DWTS could increase dissolved organic carbon (DOC) concentration and lead to the accumulation of non-biodegradable humic acid-like substance in aerobic and anaerobic digestion liquid. The dehydrogenase activity (DHA) values of anaerobic EAS were higher than aerobic EAS. DWTS could reduce DHA for both EAS. These results indicate that potential risk of release of DOM should be considered when reusing DWTS in future research.

Layered nickel-iron oxide/hydroxide nanosheets have proven to be the most efficient catalyst for the water oxidation reaction. Introducing structural defects to the nanosheets is a particularly attractive method for increasing the number of active sites and tailoring the intrinsic electronic properties. Herein, defects were introduced on Ni-Fe nanosheets through sequentially electrodoping and dedoping the surface of the material with tetramethylammonium ions. The as-prepared defect-rich Ni-Fe nanosheets showed an enhanced catalytic performance for the oxygen evolution reaction (OER) compared with conventional NiFe layered double hydroxides (LDHs), exhibiting an overpotential of only 172 mV at the current density of 10 mA cm-2 . The relationship between pH and OER activity indicated that the lattice oxygens participated in the catalytic OER process as active sites. This work provides new insights into the understanding of the structure-activity relationship of layered materials and helps to develop new methods to implement defects on such frameworks aided by organic molecules.

N-type silicon is a kind of semiconductor with a narrow band gap that has been reported as an outstanding light-harvesting material for photoelectrochemical (PEC) reactions. Decorating a thin catalyst layer on the n-type silicon surface can provide a direct and effective route toward PEC water oxidation. However, most of catalyst immobilization methods for reported n-type silicon photoanodes have been based on energetically demanding, time-consuming, and high-cost processes. Herein, a high-performance NiFeP alloy (NiFeP)-decorated n-type micro-pyramid silicon array (n-Si) photoanode (NiFeP/n-Si) was prepared by a fast and low-cost electroless deposition method for light-driven water oxidation reaction. The saturated photocurrent density of NiFeP/n-Si can reach up to ∼40 mA cm-2, and a photocurrent density of 15.5 mA cm-2 can be achieved at 1.23 VRHE under light illumination (100 mW cm-2, AM1.5 filter), which is one of the most promising silicon-based photoanodes to date. The kinetic studies showed that the NiFeP on the silicon photoanodes could significantly decrease the interfacial charge recombination between the n-type silicon surface and electrolyte.

Transformerless grid-connected inverters are of great industrial value in photovoltaic power generation. However, the direct current (DC) induced into the inverter’s output degrades the power quality of the grid. Recently, a back-propagation neural work proportional−integral−derivative (BP-PID) scheme has proven helpful in solving this problem. However, this scheme can be improved by reducing the suppressing time and overshoot. A genetic algorithm (GA)-based DC current minimization scheme, namely the genetic-algorithm-based BP-PID (GA-BP-PID) scheme, was established in this study. In this scheme, GA was used off-line to optimize the initial weights within the BP neural network. Subsequently, the optimal weight was applied to the online DC current suppression process. Compared with the BP-PID scheme, the proposed scheme can reduce the suppressing time by 59% and restrain the overshoot. A prototype of the proposed scheme was implemented and tested on experimental hardware as a proof of concept. The results of the scheme were verified using a three-phase inverter experiment. The novel GA-PB-PID scheme proposed in this study was proven efficient in reducing the suppressing time and overshoot.

As the proportion of flexible load resources in smart grids continues to rise, resulting in increasingly complex grid structures, significant changes in grid characteristics, and increased risks to grid operation and control, it will be difficult to intelligently regulate the grid solely by relying on traditional resource regulation methods, and the dispatchable space for traditional resources will become smaller and smaller. To this end, this paper conducts an exploratory investigation on the modeling techniques for flexible loads participation in smart grid dispatching. First, a classification of the flexible loads involved in grid regulation is made. Secondly, according to the flexible load classification, the modeling techniques of different classes of flexible loads are reviewed and studied; then, the flexible load dispatching modes for different operating states and different control tasks, and under different control methods are discussed deeply. Moreover, the technological economics and feasibility of these different flexible load dispatching modes are compared. Finally, an outlook and conclusion are made.

As the world’s largest consumer of coal, China is now facing serious pollution of atmospheric polycyclic aromatic hydrocarbons (PAHs) produced by coal utilization processes, i.e., coal-related PAHs, which should be of concern for relevant policy-makers. Based on the interrelationships among coal-related PAHs emission, coal consumption and socio-economic development, this study applied a coupled method of system dynamics (SD) and geographic information system (GIS) to successfully model the spatiotemporal changing processes of coal-related PAHs emission reduction in China’s 31 provinces. In these models, four different policies including industry structure adjustment, energy consumption structure adjustment, industrial emission control and household emission control were quantitatively designed to evaluate the emission reduction differences from national and provincial perspectives. And then, cluster analysis was used to identify the provinces with similar policy effects. The results indicated that, without any policy stimulation, atmospheric coal-related PAHs emission in China would maintain a gradual growth trend. The implementation of energy consumption structure adjustment had better national emission reduction effect than the other three policies, while not all provinces could succeed in emission reduction when the four policies were implemented, respectively. Besides, the different policy effects among provinces resulted from their development discrepancies in industry structure, energy structure and emission source characteristics. Therefore, to simultaneously realize the maximum national emission reduction effect and the integrated emission reduction for different provinces, all provinces should take energy consumption structure adjustment as the guiding policy and consider their targeted policies as supplementary. In short, the coupled SD-GIS method can be used to comprehensively analyze the spatiotemporal variations of unconventional atmospheric pollutants and the specific impacts of pollution control policies, which will provide a theoretical basis for local governments to reasonably direct the coordinated development of regional economy, energy structure and environmental quality.

In order to solve the placement problem of three kinds of feeder terminal units (FTU) in the distribution network, this paper proposes a novel mathematical model. The model considers economic cost and electricity supply reliability from the perspective of life cycle cost. The reliability algorithm in this model is established for the distribution network configured with centralized feeder automation. Different evaluation indices of reliability and the importance of several kinds of customers are also considered in this model. Aiming at the reliability evaluation in this model, this paper puts forward the reliability analysis method for the distribution network with three kinds of FTUs. In view of the difficulty to express the reliability of distribution network in a formula with decision variables, and the non-deterministic polynomial hard (NP-hard) nature of this model, a variety of intelligent algorithms are applied to solve the model. The feasibility and effectiveness of the model and methods for FTUs placement optimization problem are verified by a case study of the Roy Billinton test system (RBTS) Bus 5 system.

First-row transition metal-based catalysts have been developed for the oxygen evolution reaction (OER) during the past years, however, such catalysts typically operate at overpotentials (η) significantly above thermodynamic requirements. Here, we report an iron/nickel terephthalate coordination polymer on nickel form (NiFeCP/NF) as catalyst for OER, in which both coordinated and uncoordinated carboxylates were maintained after electrolysis. NiFeCP/NF exhibits outstanding electro-catalytic OER activity with a low overpotential of 188 mV at 10 mA cm−2 in 1.0 KOH, with a small Tafel slope and excellent stability. The pH-independent OER activity of NiFeCP/NF on the reversible hydrogen electrode scale suggests that a concerted proton-coupled electron transfer (c-PET) process is the rate-determining step (RDS) during water oxidation. Deuterium kinetic isotope effects, proton inventory studies and atom-proton-transfer measurements indicate that the uncoordinated carboxylates are serving as the proton transfer relays, with a similar function as amino acid residues in photosystem II (PSII), accelerating the proton-transfer rate., Proton-coupled electron transfer (PCET) process is very important for water oxidation catalysis. Here, the authors introduced uncoordinated carboxylate in the second-coordination-sphere of Ni-Fe coordination polymer catalyst as an internal base to promote the water oxidation kinetics by such PCET process.

A simple and low-cost fabrication method is needed to obtain effective and robust heterogeneous catalysts for the oxygen evolution reaction (OER). In this study, an electrocatalyst FeNiOx Hy with a hierarchical structure is synthesized on nickel foam by a simple fabrication method through anion exchange from a metal phosphate to a metal hydroxide. The as-fabricated FeNiOx Hy electrode requires overpotentials of 206 and 234 mV to deliver current densities of 10 and 50 mA cm-2 , respectively. The catalytic performance of FeNiOx Hy is superior to that of most previously reported FeNi-based catalysts, including NiFe layered double hydroxide. The catalyst also shows good long-term durability at a current density of 50 mA cm-2 over 50 h with no activity decay under 1 m KOH. By comparison to the directly electrodeposited FeNi hydroxide in morphology and electrochemical properties, the improved activity of the catalyst could be mainly attributed to an enhancement of its intrinsic activity, which was caused by the anion exchange of phosphate to (oxy)hydroxide. Further studies by cyclic voltammetry indicated a stronger interaction between Ni and Fe from the negative shift of the oxidation peak of Ni2+ /Ni3+ in comparison with reported FeNiOx Hy , which promoted the generation of active Ni3+ species more easily. This work may provide a new approach to the simple preparation of effective and robust OER catalysts by anion exchange.

Better understanding the responses of riverbed sediment bacteria to heavy metals is a key for considering using riverbed sediment bacterial community as an indicator of river water contamination by heavy metals. For this, integrated evaluation based on bacterial density, activity and community structure through incubation experiments under well-controlled conditions is necessary to obtain more closely relevant findings that are difficult to achieve through field studies. The findings may also include those that can serve as new evidence to clarify contrary findings reported in previous studies. In this study, sequencing batch incubation experiments were performed using sediment suspensions from three rivers with catchment of different land covers and uses. The effects of four metals (Pb, Cr, Cd and Cu) were investigated by spiking them separately under three different concentration levels. Glucose was added once every day as the carbon source throughout the whole incubation lasted for 30 days. The changing trends of the density of general and heterotrophic bacteria showed clearly that the responses of sediment bacteria to Cu were obviously stronger, followed by that to Cd; whereas, the responses to Pb and Cr were not apparent. For incubation with Cu, a short-term inhibition effect appeared in the initial 3 days and was then followed by a long-term promotion effect reflected by obvious increases of bacterial density against control. In regard of bacterial activity evaluated based on the first-order consumption rate for glucose, a trend of decreases was revealed. The results of PCR-DGGE and sequence analysis of extracted 16S rDNA further suggested there were bacterial species that had strong tolerance against the metal and could grow readily to become new dominating ones. The existence of such bacterial species was inferred as the reason leading to the observed increases of bacterial density during incubation with the metal.

Summary Research on the storage of solar energy in terms of hydrogen or carbon-based fuels by using sunlight to split water or to reduce CO 2 , respectively, has gained significant attention in recent years. Among reported water-splitting systems, one approach has focused on hybrid systems with molecular catalysts or molecular light-harvesting systems that are combined with nanostructured materials. In this perspective we summarize recent developments in operation and fabrication strategies for various water-splitting devices constructed from electrodes (electrochemical cells) or photoelectrodes (photoelectrochemical cells) using molecular engineering. We also provide insights into the factors that influence device efficiency and stability, and provide guidelines for future fabrication strategies for more advanced devices.

Thermoelectric generation (TEG) system is designed to recover waste heat generated in industrial production and daily life with disadvantage of low power generation efficiency. Since non-uniform temperature distribution (NTD) easily gives rise to multiple local maximum power points (LMPPs) for centralized TEG systems, conventional maximum power point tracking (MPPT) methods is likely to lead to a low-quality LMPP. Hence, a novel adaptive rapid neural optimization (ARNO) approach is proposed to capture maximum power point (MPP). Particularly, generalized regression neural network (GRNN) is devoted to construct a proper mapping between control input of duty cycle and power output of TEG system, thus ARNO can implement an efficient search for MPP. In order to reduce possible instability caused by manual tuning, Bayesian optimization (BO) is adopted to adaptively select optimal parameters of GRNN. Compared to conventional MPPT methods, four simulations are carried out to verify the feasibility and advantages of ARNO, start-up experiment, step temperature variation, stochastic change of temperature, and sensitivity analysis included. Further, dSpace platform based hardware-in-the-loop experiments are performed to verify the feasibility of the proposed method.

Microbial fuel cell (MFC) is commonly used for easily biodegradable substances, yet its application for high strength phenolic wastewater treatment remains a challenge. This study incorporates lignite activated coke (LAC) into MFC to alleviate the inhibition of phenol and facilitate power generation of MFC. The power generation and phenol degradation in both LAC-MFC and control MFC were investigated at phenol concentrations of 500 mg/L, 700 mg/L and 1000 mg/L. The results showed that the maximum power density in LAC-MFC was maintained in the range of 252.3–278.7 mW/m2 when the phenol concentration increased from 500 mg/L to 1000 mg/L, whereas it was decreased from 246.5 mW/m2 to 167.5 mW/m2 in control-MFC. This corresponds to a high phenol removal of 89.4% to 94.5% in LAC-MFC but a significant decrease from 80.7% to 50.8% in control MFC. The inhibition coefficient (Ki) calculated from Haldane inhibition model decreased by 24.3% in LAC-MFC compare with control MFC, suggesting that the stress of high concentrations of phenol on MFC was largely relieved. In addition, the phenol degradation intermediate products of 2-hydroxymuconic semialdehyde, 4-hydroxybenzoic acid, 4-hydroxy-3-methylbenzoic acid were apparently lower in LAC-MFC than control MFC, indicating that the biodegradation of phenol was enhanced in LAC-MFC. High-throughput sequencing analysis revealed that Pseudomonas, Desulfuromonas, and Hydrogenophaga might be associated with phenol degradation and power generation in LAC-MFC. Because of its effectiveness in alleviating the toxic effects of phenol, LAC packing is a promising MFC technology for high strength phenolic wastewater treatment.

The adsorption characteristics of natural organic matter (NOM) were investigated on the basis of fluorescence excitation emission matrix (EEM) by using four different coal-based activated carbons (ACs). For each AC, batch adsorption isotherms were analyzed using a modified Freundlich isotherm model on the basis of the fluorescence intensity of three major fluorescence peaks appeared in the fluorescence EEM reported to be reflective of the humic acid-like (P1), fulvic acid-like (P2) and aromatic protein-like (P3) substances, respectively, together with the well-used overall quality indices of dissolved organic carbon (DOC) and ultraviolet absorbance at the wavelength of 260 nm (UV260). It was found that, for all five quality indices, the adsorption capacity differed with the ACs used, and the modified Freundlich isotherm constant K estimated for P1, P2 and P3 was in close correlation with that of the total organic matter evaluated by DOC. Moreover, no matter which AC was concerned, the magnitude of the estimated K and the removal rate over a broader range of AC dose for P3 were apparently smaller than those for P1 and P2, suggesting the adsorbability of aromatic protein-like substances was lower than that of the humic acid-like and fulvic acid-like substances. The dependency of the adsorption capacity of NOM on the volume of pores in some specific size ranges of the ACs was also revealed.

It is difficult – though important – to assess the necessary allocation of increasingly scarce water resources and yield estimation, by determining the exact amount of evapotranspiration ( ET ) and the partitioning of ET into transpiration ( T ) through the stomata of plants and evaporation ( E ) from the soil. An accurate and effective method for ET partitioning and estimation is, therefore, desirable. This paper aims to evaluate the performance of two main models for ET partitioning and estimation in terms of feasibility and accuracy: the AquaCrop (Version 4.0) model, and the SIMDualKc model. Field experiments were carried out between 2011 and 2015 in an arid region of Northwest China on two sites using full and deficit irrigation under plastic film-mulch, with the ET of maize for seed production and its partitioning components ( T and E ) being strictly measured by using the eddy covariance (EC) system or the sap flow system and micro-lysimeter cylinders. Subsequently, part of the measured data was used to calibrate the two models, so that the calibrated models could then be used to assess whether the agreement between simulation and measurement had proved successful, thus validating the models, or not. The results showed that the two models performed well with regard to their simulation of ET and T under full irrigation conditions. Under deficit irrigation conditions, the ET and T values simulated by the AquaCrop model were much closer to the actual measurement when compared with the results simulated by the SIMDualKc model. This was particularly the case when the soil was re-watered after a period of long-term water stress. For the simulated E , however, both models generated data that were distant from the actual measurements taken under full or deficit irrigation conditions using plastic film-mulch, although when the SIMDualKc model simulated E data, it came closer to the measurement than did the AquaCrop model. The comparison of two models in terms of their accuracy and feasibility based on the data analysis is discussed.

The effect of mixed feeding of anaerobically cultured waste activated sludge (WAS) on electricity generation of MFC from solid potato waste was investigated by focusing on the major expected role of WAS as an accelerator for hydrolysis of solid potato and a side concurrent role as additional substrate besides solid potato. Columbic efficiency was significantly enhanced from 6.1 to 31.1% when the cultured WAS was mixed at the ratio of 1:4. This effect was associated with the accelerated hydrolysis rate from 0.056 to 0.089 day −1 due to the involvement of bacteria from the WAS. The final utilization of the feedstocks (evaluated by COD Cr ) varied within 39.5–89.6%, following the order of potato > mixture of potato & WAS/inactivated WAS > inactivated WAS > WAS. Stable isotope ratio (δ 13 C) analysis indicated that, for the mixed feedstocks, WAS was more easily digested than potato, making the mass fractions of potato and WAS remaining after treatment different from those before treatment.

The use of cobalt porphyrin complexes as efficient and cost-effective molecular catalysts for water oxidation has been investigated previously. However, by combining a set of analytical techniques (electrochemistry, ultraviolet–visible spectroscopy (UV–vis), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and synchrotron-based photoelectron spectroscopy (SOXPES and HAXPES)), we have demonstrated that three different cobalt porphyrins, deposited on FTO glasses, decompose promptly into a thin film of CoOx on the surface of the electrode during water oxidation under certain conditions (borate buffer pH 9.2). It is presumed that the film is composed of CoO, only detectable by SOXPES, as conventional techniques are ineffective. This newly formed film has a high turnover frequency (TOF), while the high transparency of the CoOx-based electrode is very promising for future application in photoelectrochemical cells.

One of the grand challenges for developing scalable and sustainable hydrogen producing systems is the lack of efficient and robust earth-abundant element based catalysts for the hydrogen evolution reaction (HER). Herein, a hierarchically structured Ni–Co–P film was fabricated via a gas templating electro-deposition method. This film exhibits remarkably high catalytic performance for the HER in 1 M KOH with respective current densities of −10 and −500 mA cm−2 at the overpotentials of −30 and −185 mV with a Tafel slope of 41 mV dec−1. A controlled potential electrolysis experiment demonstrates that the as-prepared Ni–Co–P film is an efficient and robust catalyst with a faradaic efficiency close to 100%. Systematic characterization suggests that the unique hierarchical structure and the mutual participation of nano-sized Ni/Co based components are responsible for the high HER catalytic activity.

Remote sensing provides an effective way for the estimation of regional evapotranspiration, therefore, a reliable scaling-up method from instantaneous evapotranspiration (ET) to daily ET is of great importance. In this paper, five commonly used scaling-up methods estimating daily ET from hourly latent heat measurements were compared under different energy and crop growing conditions. Field data collected during the whole growing season at 1.0 h intervals by eddy covariance system in North China were used. Evaporative fraction (EF), reference evaporative fraction (Kc), crop coefficient (modified-Kc) and surface resistance (rc) varied slightly during the daytime, which gave a solid theoretical basis for the scaling-up methods based on the constant value of these parameters. In most cases, the EF and Kc methods performed better than the others, the relative bias from 9:00–16:00 for the two methods ranged from −11.2% to 5.9% and −6.6% to 4.8%, respectively. The EF method was applicable when surface energy was limited, when Rn was less than 50 W m−2; the average modified coefficient of efficiency of EF method during the daytime from 9 am to 5 pm was 0.68, which is around twice that of the second best method. The Kc and the modified-Kc methods were applicable when surface energy was relatively large. The performance of the five methods didn't seem sensitive to variation of leaf area. Overall, the Kc and EF methods performed better, especially between 11:00 and 15:00. The results of this paper could be useful for optimisation of ET models.

New star-shaped and efficient hole-transporting materials based on a 1,1′-bi-2-naphthol central core for perovskite solar cells are developed via facile synthesis. The 1,1′-bi-2-naphthol is first applied into the field of perovskite solar cells. The 2,7-carbazole-bis(4-methoxy-phenyl)-amine and 3,6-carbazole-bis(4-methoxy-phenyl)-amine are used as end groups. A reference compound based on a 3,3′-biphenyl core is prepared as well. The new materials have suitable highest occupied molecular orbital levels to match well with the valence band of CH3NH3PbI3, and they all exhibit a glass transition temperature higher than 160 °C. A device fabricated by hole-transporting materials based on 1,1′-bi-2-naphthol and 2,7-carbazole-bis(4-methoxy-phenyl)-amine in conjunction with a carbon counter electrode achieves the highest power conversion efficiency of 8.38% under the illumination of 100 mW cm−2, which is comparable to that fabricated by commercial spiro-OMeTAD (8.73%). Dark current, IPCE and IMVS measurements are also discussed. The introduction of 2,7-carbazole-bis(4-methoxy-phenyl)-amine onto the 1,1′-bi-2-naphthol central core tends to enhance Jsc of a device, and 3,6-carbazole-bis(4-methoxy-phenyl)-amine improves Voc. This work provides a new series of hole-transporting materials to fabricate economic and efficient perovskite solar cells.

Benzothiadiazole (BTZ)-based dyes incorporating dithieno[3,2- b :2′,3′- d ]pyrrole (DTP) π-linker has been synthesized for fabricating efficient dye-sensitized solar cells (DSSCs). A reference dye with ethylenedioxythiophene (EDOT) π-linker has also been prepared. The introduction of DTP broadens absorption, provides a more planar skeleton, and reduces HOMO and LUMO energy gap. IMVS and EIS measurements are used to investigate interfacial electron transfer processes of device. Dyes incorporating DTP exhibit more effective inhibition of charge recombination and more conducive to electron injection than the reference dye with EDOT. Therefore, much higher efficiency is obtained in device fabricated by DTP-based dyes, and the best performance achieves a power conversion efficiency of 8.14% by using Co-phen based electrolyte. In contrast, device based on the reference dye reaches 5.22% at most. IPCE characterizations and the effect of Co-bpy and I − /I 3 − redox couple are also discussed. The DTP moiety is a good candidate for the design of BTZ-based sensitizers used in DSSCs.

The characteristics of natural organic matter (NOM) released to water from a soil environment were investigated based on the release potential and the quality indexes of SUVA, fluorescence EEM and molecular weight distribution using eight forest and agricultural soils collected from a representative river catchment (Kani River catchment in Gifu, Japan). The content of organic matter (OM) and its release potential to water differed obviously with type of soil origin, in the following order: vegetable field (VF) < paddy field (PF) < broadleaf forest (BF) < coniferous forest (CF) and VF < PF < CF < BF, respectively. For the released NOM, SUVA under different pH conditions decreased in the following order: neutral condition [3.6-24.0 m-1/(mg/L)] > basic condition [3.5-8.0 m-1/(mg/L)] > acidic condition [2.5-3.0 m-1/(mg/L)]. Humic acids (P1), fulvic acids (P2) and protein-like substances (P3) were the main components of the NOM released under neutral condition. The proportion of P1 and P2 released from the forest soils was lower than that from the agricultural soils. Marked differences in UV-absorbing constituents of NOM between forest and agricultural soils were found in the peak with a molecular weight of about 9800 g/mol identified as PSS (polystyrene sulfonate).

The effect of varying the ratio of cooked to uncooked potato in the performance of microbial fuel cell (MFC) treating common potato waste was investigated. Four MFCs were fed with a ratio of cooked (boiled) to uncooked (i.e. waste) potato of 0, 48.7, 67.3 and 85.6%. Respectively, the columbic efficiency was estimated as 53.5, 70.5, 92.7 and 71.1%, indicating significantly enhanced electricity generation and waste degradation at an initial feedstock mixing ratio of 2/3 cooked to 1/3 uncooked potato. The hydrolysis rate parameter (estimated using a first-order sequential hydrolysis and degradation model) increased from 0.061 to 0.191 day − 1 as cooked potato was added which increased electricity generation efficiency from 24.6 to 278.9 mA/m 2 /d and shortened the startup time for maximum current density from 25 to 5 days. The potato slurries' chemical oxygen demand (COD) decreased by 86.6, 83.9, 84.1 and 86.3%, respectively, indicating no relationship exists between the fraction of boiled potato and the amount of COD reduction.

Heavy metals are toxic to microorganisms at specific concentrations and can have a serious effect on the efficiency of biological wastewater treatment plants. The wastewater treatment performance and bacterial communities of activated sludge were investigated at different heavy metal concentrations (0.1–10 mg L−1 for Cd(II), Pb(II) and 1–100 mg L−1 for Cu(II)) in a well-controlled semi-continuous reactor in 30 d period. Glucose was added once every 8 h as the carbon source throughout the experiment. The heavy metal toxicity was related to chemical oxygen demand (COD), total organic carbon (TOC), three-dimensional fluorescence excitation-emission matrix (EEM) spectroscopy, bacterial activity and community composition. The first-order consumption rate for glucose showed that the activity was decreasing in comparison to the control. The COD removal efficiency was also decreased from 87% to 26% in all the reactors under different heavy metal concentrations treatment. The PCR-DGGE and sequencing results revealed that the bacterial diversity showed evident variations under heavy metal stress owing to the potential toxicity of heavy metals. At the genus level, Pedobacter steynii and Flavobacterium, were only tolerant to Cu(II) at 100 mg L−1, while Rhodanobacter thiooxydans resisted to all heavy metal concentrations except Cu(II) 100 mg L−1. Cluster analysis and Principal component analysis (PCA) revealed that the microbial community in Cu(II) was different from the sludge samples treated with Cd(II) and Pb(II) concentrations. The study indicated that it is necessary to identify the metal tolerant species of bacteria for maintaining good performance of biological wastewater treatment plants.

It is well known that path planning has always been an important study area for intelligent ships, especially for unmanned surface vehicles (USVs). Therefore, it is necessary to study the path-planning algorithm for USVs. As one of the basic algorithms for USV path planning, the rapidly-exploring random tree (RRT) is popular due to its simple structure, high speed and ease of modification. However, it also has some obvious drawbacks and problems. Designed to perfect defects of the basic RRT and improve the performance of USVs, an enhanced algorithm of path planning is proposed in this study, called the adaptive hybrid dynamic stepsize and target attractive force-RRT(AHDSTAF-RRT). The ability to pass through a narrow area and the forward speed in open areas of USVs are improved by adopting the AHDSTAF-RRT in comparison to the basic RRT algorithm. The improved algorithm is also applied to an actual gulf map for simulation experiments, and the experimental data is collected and organized. Simulation experiments show that the proposed AHDSTAF-RRT in this paper outperforms several existing RRT algorithms, both in terms of path length and calculating speed.

Conventional phase-shift controlled dual active bridge (DAB) converters which operate in discontinuous current mode (DCM) are hard to realize the zero-voltage switching (ZVS) due to the light load. This paper proposed an efficiency improvement method for the DAB converter with fix-frequency hybrid discontinue current mode (HDCM). By adopting the HDCM control method, synchronous rectification and wide load range ZVS of switching devices are realized simultaneously without changing the components of the conventional DAB power stage in DCM. Besides, to further improve the conversion ratio and efficiency, the voltage-doubled rectification (VDR) is adopted. The HDCM implementation method with a digital signal processor (DSP) is proposed. A 200W laboratory prototype is designed to validate the correctness of HDCM. Compared to the conventional DAB converter which operates in DCM, experimental results demonstrate that the efficiency was increased 1.2% at 10% rated load.