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In order to improve the stability of the multi-hydro-turbine governing system with sharing one penstock (MGSSP) during operation, an intelligent CPSOGSA-based mixed H 2 / H ∞ robust controller with an integrator is proposed. The excellent control performance of the H 2 / H ∞ robust controller is used to stabilize the system. Firstly, the mathematical model of the MGSSP is derived from the transfer function. Secondly, the robust controller is designed based on the linear matrix inequality (LMI), considered the optimal and robust performance. The modified hybrid PSOGSA with chaotic maps algorithm (CPSOGSA) is also introduced in the design process to ensure the controller is optimal. The designed robust controller is simple in structure, low in order, and easy to implement. Simulation experiments show that the CPSOGSA can complete the optimization of the controller with less than ten iterations. The designed robust controller can stabilize the system in less than 10 s for different operating conditions. The robust controller enables the controlled object to exhibit better dynamic performance than the conventional controller. The research results can provide a reference for the control application of the extended operation of the hydro-turbine governing system (HTGS). [ABSTRACT FROM AUTHOR]

Due to the stochastic grid loads and intermittent renewable energy sources in today's power grid, hydro-generator and grid system stability is increasingly dependent on the hydro-turbine governing system (HTGS). For the HTGS with external disturbances and system uncertainties, an intelligent nonlinear robust controller (INRC) based on state-dynamic-measurement feedback linearization (SDMFL) is proposed to enhance the HTGS's control performance in this paper. This strategy establishes a dynamic output function including actuator displacement, generator rotor angle, and turbine parameters. The relationship between dynamic output and control input is derived based on this function to establish the corresponding linear state-space model. Then, the mixed H 2 / H ∞ robust controller based on the linear model is designed to suppress the effects of external disturbances and system uncertainties on the system performance. In addition, the controller performance is optimized by levy flight and chaos theory-based gravitational search algorithm (LCGSA), resulting in the INRC. Simulations are performed in MATLAB, and the results are compared with the nonlinear robust controller (NRC) and PID controller. The results show that the proposed controller INRC improves the control performance of nonlinear HTGS with smaller overshoot and shorter adjustment time in all cases. • Design of nonlinear robust controller based on SDMFL method for HTGS. • Application of LCGSA algorithm for optimal tuning of NRC parameters. • Damping the speed oscillations against large fluctuations in grid power. • Excellent damping efficiency, especially, low overshoot, steady-state error, and settling time. • Study of robustness of HTGS against variations of system parameters. [ABSTRACT FROM AUTHOR]

Mesoporous metal-based materials (MMBMs) have received unprecedented attention in catalysis, sensing, and energy storage and conversion owing to their unique electronic structures, uniform mesopore size and high specific surface area. In the last decade, great progress has been made in the design and application of MMBMs; in particular, many novel assembly engineering methods and strategies based on amphiphilic block copolymers as structure-directing agents have also been developed for the "bottom-up" construction of a variety of MMBMs. Development of MMBMs is therefore of significant importance from both academic and practical points of view. In this review, we provide a systematic elaboration of the molecular assembly methods and strategies for MMBMs, such as tuning the driving force between amphiphilic block copolymers and various precursors (i.e., metal salts, nanoparticles/clusters and polyoxometalates) for pore characteristics and physicochemical properties. The structure–performance relationship of MMBMs (e.g., pore size, surface area, crystallinity and crystal structure) based on various spectroscopy analysis techniques and density functional theory (DFT) calculation is discussed and the influence of the surface/interfacial properties of MMBMs (e.g., active surfaces, heterojunctions, binding sites and acid–base properties) in various applications is also included. The prospect of accurately designing functional mesoporous materials and future research directions in the field of MMBMs is pointed out in this review, and it will open a new avenue for the inorganic–organic assembly in various fields. [ABSTRACT FROM AUTHOR]

Cotton-like graphitic carbon nitride @ layered double hydroxides nanocomposites (g-C 3 N 4 @Ni-Mg-Al-LDH) was fabricated using lamellar g-C 3 N 4 and rod-like Ni-Mg-Al-LDH as monomer molecules by one-step hydrothermal synthesis strategy, and it exhibited superior adsorption performance to U(VI) from wastewater based on strong synergistic effects among metal–oxygen functional groups (Mg O, Al O and Ni O) and free-metal functional groups (O C O, C O C, C O, C C and NH 2 / NH /= N ). The adsorption of U(VI) on g-C 3 N 4 @Ni-Mg-Al-LDH was controlled by outer-sphere surface complexation or ion exchange, which was evidenced with batch adsorption experiments and SEM, EDS, elemental mapping, FT-IR, XRD and XPS characterizations. Moreover, the maximum adsorption capacity of U(VI) on g-C 3 N 4 @Ni-Mg-Al-LDH (99.7 mg·g −1 ) was approximately 1.5 times higher than that of U(VI) on Ni-Mg-Al-LDH (59.8 mg·g −1 ) and approximately 3.0 times higher than that of U(VI) on g-C 3 N 4 (31.1 mg·g −1 ) at 298.15 K, and a multilayer adsorption was existed in a low concentration of UO 2 2+ , while a monolayer adsorption was appeared in a high concentration of UO 2 2+ . The results also showed that the adsorption reaction of U(VI) was a typical endothermic and spontaneous process because of ΔH θ > 0, ΔS θ > 0 and ΔG θ < 0. Thus, it can provide new highlights to improve the physicochemical properties of low-efficiency adsorbents based on synergistic effect through polymerization reaction, and it can be selected as superior synthetic route for the synthesis of excellent adsorbents in environmental remediation. [ABSTRACT FROM AUTHOR]

Because a single monitoring index cannot fully reflect the overall operating status of the hydropower unit, a comprehensive state evaluation model for hydropower units based on the analytic hierarchy process (AHP) and the Gaussian threshold improved fuzzy evaluation is proposed. First, the unit equipment was divided into a hierarchical system, and a three-tier structure system (target layer-project layer-index layer) of the unit was constructed, and the weight of each component in the system was determined by the comprehensive weighting method. Secondly, according to the characteristics of the normal distribution of the historical health data of the unit, the upper and lower limits of the index were determined based on the Gaussian threshold principle, the real-time monitoring index degradation degree was calculated according to the index limit, and the degradation degree was applied to the fuzzy evaluation model to obtain the fuzzy judgment matrix. The result of assessment was divided into four sections: good, qualified, vigilant, and abnormal. Finally, combined with the unit hierarchical structure system, the weighted calculation of the fuzzy judgment matrix of each indicator, the overall fuzzy judgment matrix of the upper-level indicators of the unit was obtained, and the operating status of the unit was judged according to the matrix. Taking a real power plant unit as an example, the model was verified, and compared with other evaluation methods, the effectiveness and advantages of the proposed method were verified. In addition, the method proposed in this paper effectively solved the problems of index weighting and index limit determination in the existing model of unit condition evaluation. [ABSTRACT FROM AUTHOR]

With the development of internet of things and artificial intelligence electronics, metal oxide semiconductor (MOS)‐based sensing materials have attracted increasing attention from both fundamental research and practical applications. MOS materials possess intrinsic physicochemical properties, tunable compositions, and electronic structure, and are particularly suitable for integration and miniaturization in developing chemiresistive gas sensors. During sensing processes, the dynamic gas–solid interface interactions play crucial roles in improving sensors' performance, and most studies emphasize the gas–MOS chemical reactions. Herein, from a new view angle focusing more on physical gas–solid interactions during gas sensing, basic theory overview and latest progress for the dynamic process of gas molecules including adsorption, desorption, and diffusion, are systematically summarized and elucidated. The unique electronic sensing mechanisms are also discussed from various aspects including molecular interaction models, gas diffusion mechanism, and interfacial reaction behaviors, where structure–activity relationship and diffusion behavior are overviewed in detail. Especially, the surface adsorption–desorption dynamics are discussed and evaluated, and their potential effects on sensing performance are elucidated from the gas–solid interfacial regulation perspective. Finally, the prospect for further research directions in improving gas dynamic processes in MOS gas sensors is discussed, aiming to supplement the approaches for the development of high‐performance MOS gas sensors. [ABSTRACT FROM AUTHOR]

[Display omitted] A 1.5 μm-thick amorphous SnO 2 interlayer is deposited via a facile and scalable sol-gel method to achieve improved wettability of garnet-type electrolyte with Li metal. • Amorphous SnO 2 interlayer is deposited on LLZTO by low-cost sol–gel method. • The Li/LLZTO interface resistance is significantly reduced from 1470 Ω cm2 to 38 Ω cm2. • The Li/SnO 2 -LLZTO-SnO 2 /Li symmetric cell stably cycled for 800 h. Garnet-type electrolytes (LLZO) have received increasing attention due to their high ion conductivity and good compatibility with Li anode. However, LLZO-based solid state batteries are hindered by the poor interface contact between Li metal and electrolytes. To this end, a 1.5 μm-thick amorphous SnO 2 layer has been deposited ontogarnet pellet via facile sol–gel method to improve its wettability with Li metal. By introducing the layer, the Li/LLZTO interface resistance is reduced from 1470 Ω cm2 to 38 Ω cm2. The Li/LLZTO/Li symmetric cell shows good cycling performance at 0.1 mA cm−2 for over 800 h. [ABSTRACT FROM AUTHOR]

Long-term rotary tillage leads to thinning of the soil layer and low nitrogen use efficiency of crops, resulting in a decrease in crop yield and quality. Therefore, a new alternative method to improve nitrogen use efficiency of crops needs to be found urgently. Here, we analyzed the effects of a new smash ridge tillage method combined with reduced nitrogen application on tobacco growth and development, and nitrogen use efficiency and its economic benefits. The results showed that, compared with conventional tillage and nitrogen application of 180 kg N ha−1, smash ridge tillage and a 30% reduction in nitrogen rate resulted in greater root length density, more primary lateral roots and greater rooting depth in the subsoil. It is also beneficial to maintain a high level of biomass and nitrogen accumulation in the later growth period, increasing the output value of tobacco by CNY 1588.35 ha−1 and reducing the cost by CNY 974.1 ha−1 on average in two years. In conclusion, our study highlights the economic benefits of smash ridge tillage and nitrogen reduction for tobacco growth and development, and considers them an effective method for improving agricultural productivity and nitrogen use efficiency. [ABSTRACT FROM AUTHOR]

The hydraulic turbine governing system (HTGS) is a complex nonlinear system that regulates the rotational speed and power of a hydro-generator set. In this work, an incremental form of an HTGS nonlinear model was established and the Takagi–Sugeno (T-S) fuzzy linearization and mixed H2/H∞ robust control theory was applied to the design of an HTGS controller. A T-S fuzzy H2/H∞ controller for an HTGS based on modified hybrid particle swarm optimization and gravitational search algorithm integrated with chaotic maps (CPSOGSA) is proposed in this paper. The T-S fuzzy model of an HTGS that integrates multiple-state space equations was established by linearizing numerous equilibrium points. The linear matrix inequality (LMI) toolbox in MATLAB was used to solve the mixed H2/H∞ feedback coefficients using the CPSOGSA intelligent algorithm to optimize the weighting matrix in the process so that each mixed H2/H∞ feedback coefficients in the fuzzy control were optimized under the constraints to improve the performance of the controller. The simulation results show that this method allows the HTGS to perform well in suppressing system frequency deviations. In addition, the robustness of the method to system parameter variations is also verified. [ABSTRACT FROM AUTHOR]

To achieve optimal control under all operating conditions for hydropower units, an intelligent robust controller (NSFLIRC) is proposed based on a novel state space equation and state-dynamic-measurement feedback linearization. Firstly, a nonlinear hydro-turbine regulation system (HTRS) model is constructed and a novel high-order state space equation model of HTRS is derived considering system tracking deviation. Then, the robust control for HTRS is achieved by combining the novel high-order state space equation and H ∞ control. Furthermore, the slime mold algorithm (SMA) is improved by incorporating hybrid chaotic mapping functions, Levy flight, and a nonlinear weight coefficient. The intelligent optimization of H ∞ controller parameters is realized using the improved SMA (ISMA). Finally, a nonlinear HTRS simulation platform is constructed to verify the performance of the proposed NSFLIRC. The simulation results show that when the overshoot is within a reasonable range, using NSFLIRC can respectively reduce the average values of adjusting time, rising time, overshoot, and power inversion by 46.6 %, 29.06 %, and 52.56 % comparing to the traditional PID controller under six typical operating conditions; also, the NSFLIRC has low sensitivity to changes in system parameters and most operating conditions, and has strong robustness under conventional load changes and extreme three-phase short circuit conditions. • A high-precision nonlinear simulation platform of the hydraulic turbine regulation system is built. • A novel state equation of the hydraulic turbine regulation system is introduced. • The robust control strategy for hydropower units is realized under the power control mode. • The slime mold algorithm is optimized and applied. • The designed robust controller is verified under normal conditions and extreme three-phase short circuit conditions. [ABSTRACT FROM AUTHOR]

Achieving convenient, sensitive, low‐cost, and non‐contact detection of trace addictive drugs is a challenging problem. Herein, a novel ionically conductive metal‐organic framework (IC‐MOFs) is designed through a controlled interface assembly strategy. The active metal anions are incorporated into the layered MOFs with a porous structure, forming charge carriers that served as effective adsorption/binding sites for N‐methylphenethylamine (MPEA), a crucial simulator of addictive drugs. The in situ integrated Zn3(HHTP)2‐MOF sensor device designed in this study demonstrated real‐time detection of sub‐ppb level MPEA at room temperature, with an exceptionally low theoretical detection limit of 20 ppt. The overall sensing performance of this sensor surpassed all previously reported chemical sensors for detecting methamphetamine. The Zn3(HHTP)2‐MOF sensor exhibited outstanding selectivity, rapid response time (ca. 5 s), excellent long‐term stability, amenable miniaturization, and device consistency. The device successfully passed dual 85 test (500 h at 85 °C and 85% of humidity), which is rarely report previously. Density functional theoretical calculations (DFT) and spectral characterization confirmed that the prominent selectivity of Zn3(HHTP)2‐MOF toward MPEA is attributed to the strong binding ability. The general and straightforward strategy provides brand‐new route to exploiting smart sensors for drug prevention and surveillance. [ABSTRACT FROM AUTHOR]

Titania‐based materials have aroused great attention in energy conversion and photocatalytic degradation, but they suffer from the drawbacks of fast electron–hole recombination and narrow light‐adsorption range. Here, a series of heterojunction mesoporous TiO2/g‐C3N4 (mTiO2/g‐C3N4) composites with improved light‐adsorption capacity and efficient light‐capturing property are designed through a novel solid–liquid interface induced co‐assembly strategy and controlling the interface property of g‐C3N4. Through introducing Pt precursor during the synthesis, ultrasmall Pt nanoparticles are in situ generated in the mTiO2/g‐C3N4 composites, forming mesoporous Pt@TiO2/g‐C3N4 (mPt @ TiO2/g‐C3N4‐4.0) with abundant surface active sites, and huge heterojunction interfaces. The obtained mPt @ TiO2/g‐C3N4‐4.0 photocatalysts have narrow band gap (≈2.96 eV) and superior performance in promoting separation of photogenerated charge carriers. They show ultrahigh photocurrent density (≈8.3 µA cm−2) that is five times higher than that of mTiO2/g‐C3N4‐4.0 (≈1.6 µA cm−2) due to the effective charge separation between the semiconductors and Pt nanoparticles, as well as the synergistic effect at heterojunction interfaces. In addition, mPt @ TiO2/g‐C3N4 photocatalysts show excellent performance in photodegradation of rhodamine B with fast decomposition rate within 8 min. These results foresee the wide‐range applications of the composite photocatalysts potential candidates for solar‐to‐fuel conversion and environmental remediation. Ordered mesoporous crystalline Pt@TiO2/g‐C3N4 heterojunction catalyst based on hydrophilic–hydrophobic/surface‐charge controllable strategy presents excellent photodegradation efficiency for rhodamine B and photocurrent density. The heterojunction exhibits prominent light absorption capacity (200–700 nm) and electron–hole separation ability (band gap ≈2.96 eV), which opens a door for constructing highly efficient heterogeneous catalysts with uniform mesoporous structure. [ABSTRACT FROM AUTHOR]

Abstract Colloidal delivery systems are widely used in the food industry to enhance the dispersibility, stability, efficacy, or bioavailability. However, when exposed to the high temperature, delivery systems are often prone to degradation, which limits its application in thermal processing. In this paper, the effects of thermal processing on the performance of traditional protein-based or starch-based delivery systems are firstly described, including the molecular structure changes of proteins, starches or lipids, and the degradation of embedded substances. These effects are unfavorable to the application of the delivery system in thermal processing. Then, strategies of improving the heat resistance of food grade colloid delivery system and their use in frying, baking and cooking food are mainly introduced. The heat resistance of the delivery system can be improved by a variety of strategies, including the development of new heat-resistant materials, the addition of heat-resistant coatings to the surface of delivery systems, the cross-linking of proteins or starches using cross-linking agents, the design of particle structures, the use of physical means such as ultrasound, or the optimization of the ingredient formula. These strategies will help to expand the application of heat-resistant delivery systems so that they can be used in real thermal processing. [ABSTRACT FROM AUTHOR]

Hierarchical silicon dioxide-@-layered double hydroxide (SiO 2 @LDH) nanocomposites were synthesized by a facile in situ co-precipitation method, and characterized by XRD, FESEM, FT-IR and XPS in detail. The sorption of uranium (U(VI)) and methyl orange (MO) on SiO 2 @LDH were investigated as a function of pH, ionic strength, contact time and temperature. The results indicated that the sorption of U(VI) and MO were strongly dependent on pH, and weakly dependent on ionic strength, demonstrating that the interaction of U(VI) was mainly dominated by inner-sphere surface complexation and the sorption of MO was mainly attributed to electrostatic attraction due to the high removal efficiency (∼98% within 4 h for U(VI) ions, and ∼92% within 10 min for MO). The kinetics sorption of U(VI) and MO both followed the pseudo-second-order model well, suggesting that the sorption processes were chemical sorption. The sorption isotherms of U(VI) and MO on SiO 2 @LDH were well fitted by the Langmuir model, and the maximum sorption capacities of SiO 2 @LDH were calculated to be 303.1 mg·g −1 for U(VI) and 166.1 mg·g −1 for MO. The thermodynamic parameters revealed that the sorption of U(VI) and MO was spontaneous process. Integrating the experimental result analysis, the hierarchical SiO 2 @LDH may be a promising material for the efficient elimination of radionuclides and dyes from aqueous solutions in natural environmental pollution cleanup. [ABSTRACT FROM AUTHOR]

Graphical abstract Layered MoS 2 /rGO composites were synthesized successfully and exhibited superior adsorption efficiency for Pb(II) (384.16 mg g−1) through electrostatic interactions and surface complexation for environmental remidiation. Abstract In this work, a facile method was adopted to synthesize molybdenum disulfide/reduced graphene oxide (MoS 2 /rGO) composites through an l -cysteine-assisted hydrothermal technique. The as-prepared MoS 2 /rGO composites were firstly applied as adsorbents for efficient elimination of Pb(II) ions. Batch adsorption experiments showed that the adsorption of Pb(II) on MoS 2 /rGO followed pseudo-second-order kinetic model well. The adsorption of Pb(II) was intensely pH-dependent, ionic strength-dependent at pH < 9.0 and ionic strength-independent at pH > 9.0. The presence of humic acid (HA) enhanced Pb(II) adsorption obviously. The MoS 2 /rGO composites exhibited excellent adsorption capacity of 384.16 mg g−1 at pH 5.0 and T = 298.15 K, which was superior to MoS 2 (279.93 mg g−1) and many other adsorbents. The thermodynamic parameters suggested that the adsorption process of Pb(II) on MoS 2 /rGO composites was spontaneous (Δ G θ < 0) and endothermic (Δ H θ > 0). The interaction of Pb(II) and MoS 2 /rGO was mainly dominated by electrostatic attraction and surface complexation between Pb(II) and oxygen-containing functional groups of MoS 2 /rGO. This work highlighted the application of MoS 2 /rGO as novel and promising materials in the efficient elimination of Pb(II) from contaminated water and industrial effluents in environmental pollution management. [ABSTRACT FROM AUTHOR]

Herein the novel natural bimetallic oxides of perovskite oxides (CaTiO x ) and calcium aluminum oxides (CaAlO x ) were fabricated by one-step calcination-oxidation process under air conditions and were characterized using zeta potential, FT-IR, SEM, TEM, XRD, and XPS techniques. Porous and cotton-shaped irregular surface morphologies of CaTiO x and CaAlO x could provide excellent active sites and large specific surface area for the removal of U(VI) from wastewater. Based on FT-IR, XRD and XPS analyses, the enrichment of U(VI) was attributed to the abundant adsorption sites (e.g., M-O groups) of CaTiO x and CaAlO x . The consequences demonstrated that the sorption of U(VI) on CaTiO x and CaAlO x were strongly dependent on pH and weakly dependent on ionic strength at pH < 4.0, while strongly dependent on pH and ionic strength at pH > 4.0. The accordance of sorption kinetic data with the pseudo-second order model suggested that the sorption reaction was multi-stage controlled chemical process. The sorption isotherms of U(VI) can be satisfactorily simulated by the Langmuir model and the maximum monolayer sorption capacities of U(VI) were 241.71 mg·g −1 on CaTiO x and 258.29 mg·g −1 on CaAlO x at 298.15 K. In addition, the thermodynamic results pointed out that the sorption reaction was spontaneous and endothermic process. The sorption mechanism was interpreted as surface complexation and electrostatic interactions. The results demonstrated that CaTiO x and CaAlO x could be widely used as promising and cost-effective materials for the treatment of U(VI) of aqueous solutions in environmental management and pollution prevention and cure. [ABSTRACT FROM AUTHOR]

With the emerging of the Internet of Things, chemiresistive gas sensors have been extensively applied in industrial production, food safety, medical diagnosis, and environment detection, etc. Considerable efforts have been devoted to improving the gas‐sensing performance through tailoring the structure, functions, defects and electrical conductivity of sensitive materials. Among the numerous sensitive materials, mesoporous semiconductor metal oxides possess unparalleled properties, including tunable pore size, high specific surface area, abundant metal–oxygen bonds, and rapid mass transfer/diffusion behavior (Knudsen diffusion), which have been regarded as the most potential sensitive materials. Herein, the synthesis strategies for mesoporous metal oxides are overviewed, the classical functionalization techniques of sensitive materials are also systemically summarized as a highlight, including construction of mesoporous structure, regulation of micro‐nano structure (i.e., heterojunctions), noble metal sensitization (e.g., Au, Pt, Ag, Pd) and heteroatomic doping (e.g., C, N, Si, S). In addition, the structure–function relationship of sensitive materials has been discussed at molecular‐atomic level, especially for the chemical sensitization effect, elucidating the interface adsorption/catalytic mechanism. Moreover, the challenges and perspectives are proposed, which will open a new door for the development of intelligent gas sensor in various applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • Chewiness is a key indicator for consumers in the process of staple food selection. • The formation mechanisms of chewiness of common staple foods are reviewed. • The methods of regulating the chewiness of common staple foods are emphasized. • The challenges of regulating the chewiness of common staple foods are discussed. Staple foods serve as vital nutrient sources for the human body, and chewiness is an essential aspect of food texture. Age, specific preferences, and diminished eating functions have broadened the chewiness requirements for staple foods. Therefore, comprehending the formation mechanism of chewiness in staple foods and exploring approaches to modulate it becomes imperative. This article reviewed the formation mechanisms and quality control methods for chewiness in several of the most common staple foods (rice, noodles, potatoes and bread). It initially summarized the chewiness formation mechanisms under three distinct thermal processing methods: water medium, oil medium, and air medium processing. Subsequently, proposed some effective approaches for regulating chewiness based on mechanistic changes. Optimizing raw material composition, controlling processing conditions, and adopting innovative processing techniques can be utilized. Nonetheless, the precise adjustment of staple foods' chewiness remains a challenge due to their diversity and technical study limitations. Hence, further in-depth exploration of chewiness across different staple foods is warranted. [ABSTRACT FROM AUTHOR]

Generalized predictive control (GPC), which has excellent control performance and robustness, is only applicable to the control object that can be expressed in the transfer function and is difficult to be directly applied to the hydraulic turbine regulation system (HTRS) that contain extremely complex nonlinearity. Therefore, considering the practical application of GPC in a hydropower station containing the Francis turbine, the double models, real-time feedback linearization module, and a nonlinear characteristic compensator are designed, and a generalized predictive control strategy combining these modules (GPC-DM-RFLM-NCC) is proposed. Firstly, the salp swarm algorithm (SSA) is improved based on the chaotic mapping and Levy flight, an accurate nonlinear hydraulic turbine model is constructed based on the backpropagation neural network (BPNN) and improved SSA (ISSA), and an HTRS simulation platform with nonlinear characteristics is built by combining modules such as water diversion system, servo system, and generator. Then, the irrationality of the commonly used linear hydraulic turbine models in HTRS dynamic process simulation is verified through quantitative calculation. Furthermore, by combining the real-time feedback linearization method and ISSA-based nonlinear characteristic compensator, the GPC-DM-RFLM-NCC is proposed. Finally, the HTRS simulation platform, which consists of GPC, double models, real-time feedback linearization module, and nonlinear characteristic compensator, is built, and the applicability, reliability, and excellent robustness of the proposed GPC-DM-RFLM-NCC are verified by the real data of a hydropower station. • The salp swarm algorithm is optimized based on the chaotic mapping and Levy flight. • A refined model of the hydraulic turbine regulation system containing the precise hydro-turbine model is established. • The irrationality of the popular linear hydraulic turbine model is revealed through quantitative calculation. • A generalized predictive control strategy is proposed considering the nonlinearity of the hydraulic turbine. • Model mismatch caused by feedback linearization is estimated and corrected. [ABSTRACT FROM AUTHOR]

The pressure pulsation in the turbine draft tube causes vibration and active oscillation in the unit, which is a technical limitation that restricts the allowable area of unit operation. In this paper, the effect of pressure pulsation is taken into account in the turbine, a complete Simulink model of the hydropower unit is constructed, and the impact of pressure pulsation parameters on the active oscillation of the unit is investigated. Using the design concept of GPSS and combining it with fuzzy control, an F-GPSS is designed to reduce active power oscillation caused by pressure pulsation. Further, the parameters of F-GPSS are optimized by applying an improved salp swarm algorithm (ISSA) to enhance the effectiveness of F-GPSS in suppressing active oscillations. Simulation studies show that ISSA-F-GPSS can effectively suppress the active oscillations induced by pressure pulsation, and the control strategy also has good suppression for other types of active oscillations, indicating that the controller has good adaptability. This work can be applied to power production operations to facilitate a better understanding of the oscillation characteristics. [ABSTRACT FROM AUTHOR]

The health of the hydroelectric generator determines the safe, stable, and reliable operation of the hydropower station. In order to keep the hydroelectric generator in a better state of health and avoid accidents, it is crucial to detect its faults. In recent years, fault detection methods based on sound and vibration signals have gradually become research hotspots due to their high sensitivity, achievable continuous dynamic monitoring, and easy adaptation to complex environments. Therefore, this paper is a supplement to the existing state monitoring and fault diagnosis system of the hydroelectric generator; it divides the hydroelectric generator into two significant parts: hydro-generator and hydro-turbine, and summarizes the research and application of fault detect technology based on sound signal vibration in hydroelectric generator and introduces some new technology developments in recent years, and puts forward the existing problems in the current research and future development directions, and it is expected to provides some reference for the research on fault diagnosis of the hydroelectric generator. [ABSTRACT FROM AUTHOR]

Modification of starch to realize the value-added utilization of starch is a hot research topic at present. In this study, the complex composed of chitosan, betaine and vanillin with different concentrations was used as a new starch modifier to modify corn starch based on special mechanism, and the gelatinization, rheological, gel, thermal characteristics and structural characteristics of starch gel were evaluated. The gelatinization results showed that chitosan, betaine and vanillin complex can significantly increase the viscosity of starch including peak, breakdown, final and setback viscosity, which proved its potential as a gel thickener. The results of rheological properties showed that the viscoelasticity of corn starch was significantly increased after modification. The gel characteristics also presented that the modifier can promote the gel formation and can be used as gelling agent. The thermal stability of modified corn starch was also significantly improved. FT-IR and XRD results show that chitosan, betaine and vanillin can improve starch properties mainly through hydrogen bond interaction, Schiff base crosslinking and electrostatic interaction. Moreover, SEM showed the microstructure of corn starch became more orderly and regular with the addition of modifiers. The results show that the complex of chitosan, betaine and vanillin can be used as a new gel thickener and stabilizer in the industry, and has the potential for improvement. This will provide theoretical reference for expanding the application scope of starch and realizing the value-added utilization of starch. [Display omitted] • Combination of chitosan, betaine and vanillin has the potential to act as a gelling agent. • The composite gels exhibited excellent pasting and rheological properties. • The hardness and thermal stability of CS-B-C-V gels were significantly improved. • Hydrogen bond, electrostatic interaction and Schiff base bond exist in CS-B-C-V gels. • Compact structure was formed by the enhanced interaction in CS-B-C-V gels. [ABSTRACT FROM AUTHOR]

A diesel engine is a typical dynamic system. In this paper, a dynamics method is proposed to establish the Hamiltonian model of the diesel engine, which solves the main difficulty of constructing a Hamiltonian function under the multi-field coupling condition. Furthermore, the control method of Hamiltonian model structure modification is introduced to study the control of a diesel engine. By means of the principle of energy-shaping and Hamiltonian model structure modification theories, the modified energy function is constructed, which is proved to be a quasi-Lyapunov function of the closed-loop system. Finally, the control laws are derived, and the simulations are carried out. The study reveals the dynamic mechanism of diesel engine operation and control and provides a new way to research the modeling and control of a diesel engine system. [ABSTRACT FROM AUTHOR]

Starch has great potential to replace petroleum-based plastics in food packaging applications. However, starch films often exhibit poor mechanical and barrier properties, and are vulnerable to moisture and bacterial contamination. This study proved that the incorporation of eggshell powder (ES) enhanced the hydrogen bonding in starch-based films significantly, which contributed to improved tensile strength, Young's modulus, and water resistance of the films. The performance of ES-incorporated films could be optimized by adjusting the size, concentration, and surface property of ES in the film matrix. Notably, adsorbing epigallocatechin gallate (EGCG) on the surface of porous ES contributed to enhanced dispersibility of the fillers in the film matrix, which increased the tortuous path of light, water vapor, and oxygen have to take through the films, resulting in increased UV screening performance, water vapor and oxygen barrier property of the films by 60 %, 7.2 %, and 27.9 %, respectively. Meanwhile, loading EGCG in ES also enable superior antibacterial activity of the final films. This study suggests that eggshell fillers offer a sustainable means of improving the functional performance of starch-based films, which may increase their application as packaging materials in the food industry. • Eggshell waste was added to starch-based films. • Treated eggshell waste reinforced the strength and thermal stability of starch films. • Treated eggshell waste increased the water vapor and oxygen barrier properties. • Eggshell waste decreased the surface hydrophilicity of starch-based films. • Treated eggshell waste enhances the antibacterial activity of the composite films. [ABSTRACT FROM AUTHOR]

Environmental contamination of radioactive waste water has drawn major public concerns because of its serious hazard in chemical and dynamic bio-toxicities. In present work, the interaction mechanism of the important radionuclide uranium (U) and graphene oxide (GO) under aqueous conditions with varying pH levels was scrutinized by means of high-level density functional theory (DFT) together with the implicit water model. A closer look at the bonding structures and adsorption energies of 12 GO/uranyl complexes indicated that the main adsorption sites on GO were the oxygen-containing functional groups such as epoxy group, carboxyl group, and hydroxyl group. More importantly, high pH level was more favorable for the adsorption process of uranyl species on the graphene oxide due to the stronger electrostatic interaction between negatively charged O atom and uranyl ion. This conclusion was further verified by comprehensive analysis from density of state (DOS) and charge density difference. Compared to the other forms of graphene oxide, the GO containing bi-hydroxyl groups had the highest adsorption capacity towards the uranyl species. The present theoretical view point gave supplement to the experimental observations and the proposed intrinsic mechanisms may bring new insight into the environmental management of radioactive pollution. [ABSTRACT FROM AUTHOR]

The uncalcined glycerol-modified nanocrystallined Mg/Al layered double hydroxides (named as G-LDH) and calcined G-LDH (named as G-LDO) with molar ratio of Mg:Al = 3:1 were successfully synthesized using an easy and green hydrothermal method, and were characterized by scanning electron microscopy, transmission electron microscopy, N 2 Brunauer–Emmett–Teller surface area measurement, Fourier transformed infrared (FT-IR) spectroscopy and X-ray diffraction (XRD). The as-synthesized G-LDH and G-LDO were applied as adsorbents to remove methyl orange (MO) from aqueous solutions at different experimental conditions, and the results showed that the interaction of MO with G-LDH and G-LDO were strongly pH-dependent and ionic strength-independent. Kinetic study indicated the MO adsorption on G-LDH and G-LDO were well simulated by pseudo-second-order model. The MO adsorption on G-LDH and G-LDO were well simulated by Langmuir model, and the maximum adsorption capacity of G-LDO (q max = 1062.3 mg/g) was much higher than that of G-LDH (q max = 443.5 mg/g) at pH = 4.5. The thermodynamic parameters calculated from temperature-dependent isotherms indicated that the adsorption was spontaneous and exothermal process. The FT-IR and XRD analysis further evidenced that the interaction of MO with G-LDH was mainly dominated by electrostatic interaction, ion exchange, hydrogen bonding and surface complexation, whereas the uptake of MO to G-LDO was mainly attributed to electrostatic interaction and surface complexation. These results suggested that the G-LDO was a promising material for the efficient removal of organic pollutants in real environmental pollution cleanup. [ABSTRACT FROM AUTHOR]

Fe 3 O 4 nanoparticles were synthesized by hydrothermal technique and then modified with tetraethyl orthosilicate to form Fe 3 O 4 @SiO 2 nanospheres through Stöber method. The characterization results of X-ray diffraction, Fourier transformed infrared spectroscopy, transmission electron microscopy, scanning electron microscopy and magnetic measurements evidenced the successful synthesis of Fe 3 O 4 @SiO 2 nanospheres. The as-prepared Fe 3 O 4 @SiO 2 was applied as adsorbent to remove congo red (CR) from aqueous solutions at different experimental conditions, and the results indicated that CR adsorption on Fe 3 O 4 @SiO 2 was strongly pH-dependent and weakly ionic strength-dependent at relative low pH values, indicating that the adsorption was mainly dominated by electrostatic interactions. The maximum adsorption capacities of CR on Fe 3 O 4 @SiO 2 were calculated to be 54.64 mg/g from Sips model and 50.54 mg/g from Langmuir model at T = 308 K and pH = 5.3. The thermodynamic parameters calculated from temperature-dependent isotherms indicated that the adsorption of CR on Fe 3 O 4 @SiO 2 was an spontaneous and endothermic process. The CR-adsorbed Fe 3 O 4 @SiO 2 nanospheres could be easily separated from aqueous solutions using magnetic separation technique within 40 s. These results suggested that the Fe 3 O 4 @SiO 2 nanospheres might be suitable materials for the efficient separation of dye pollutants from aqueous solutions in possible real applications. [ABSTRACT FROM AUTHOR]

Long-term shallow rotary tillage has reduced the soil quality and restricted the crop yield growth of farmland in Southern China. Deep tillage can effectively loosen the soil and reduce the compaction of deep soil, while no-tillage can ensure the sustainable use of soil. In this study, we selected three paddy-upland multiple cropping rotation areas in Southern China. Two tillage regimes were carried out, one (DT) where rice straw mulching was followed by deep tillage (subsoiling 30 cm) and then, for the next three years, no-tillage in the flue-cured tobacco planting season and rotary tillage in the rice planting season vs a control (RT) where no tillage after rice straw mulching was carried out, and rotary tillage was conducted in both the flue-cured tobacco planting season and rice planting season for the next three years. We compared the yield and output value of flue-cured tobacco and grain yield under DT and RT tillage regimes in the three areas, and analyzed the economic benefits brought by DT. Furthermore, we identified the effects of DT on soil aggregates, soil organic carbon (SOC), crop growth, and nutrient uptake at the experimental site in Yunyuan. Compared with RT, DT can increase the weight proportion of macroaggregates and SOC content in the 10–30 cm soil layer and improve the stability of soil aggregates in the 0–30 cm soil layer. In 2019, the mean weight diameter (MWD) and geometric mean diameter (GMD) of the 0–30 cm soil layer increased by 0.47 mm and 0.20 mm, respectively, on average. In 2020, the MWD and GMD increased by 0.33 mm and 0.11 mm, respectively, on average. DT promoted the roots of flue-cured tobacco to extend down to the 30–40 cm soil layer, and DT flue-cured tobacco plants had more leaves, higher dry matter weight, and greater N and P absorption than RT flue-cured tobacco. These results were conducive to the increase of yield and output value of flue-cured tobacco. During the three-year test period, the yield of flue-cured tobacco increased by 4%–9%, the output value increased by 7%–13%, and the net economic benefits also increased. In the paddy-upland multiple cropping rotation areas of Southern China, DT is more conducive to the improvement of dryland crop yield than paddy field crop yield. Intermittent deep tillage (one-time deep tillage and then no tillage) is expected to provide a potential way to effectively increase production, high economic efficiency, and soil improvement in promoting sustainable agricultural development and cleaner production. • The size, fuel consumption, and cost of general operation for deep tillage machinery has been improved. • Intermittent deep tillage promoted more sensible straw mulching management strategy. • Intermittent deep tillage and straw mulching resulted in more soil macroaggregates. • Intermittent deep tillage increased carbon input and carbon storage in the subsoil. • Changes in tillage varied crop yields and economic benefits of cultivated land. [ABSTRACT FROM AUTHOR]