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The increasing volume of municipal solid waste (MSW) worldwide presents significant environmental challenges, necessitating the development of efficient waste-to-energy (WtE) solutions. Among various thermochemical methods, gasification offers a promising approach for converting MSW into syngas, which can be utilized for energy generation. This study investigates the gasification characteristics of MSW in a pilot-scale reciprocating moving-grate furnace, focusing on the effect of key operating parameters such as equivalence ratio (ER), gasification temperature, and gasifying agent-staged ratio on gasification characteristics. Seven experimental schemes were tested with varying lower heating values (LHV) of MSW (ranging from 6.98 to 15.1 MJ/kg) and throughputs (ranging from 0.77 to 1.67 tons per day) to assess the adaptability and stability of the moving-grate system under different conditions. The results indicate that an ER between 0.6 and 0.7, a gasification temperature of 760 °C, and a gasifying agent-staged ratio of 7:3 are optimal for achieving a maximum energy conversion efficiency of 71.6 %. It was observed that the LHV of syngas decreases when the gasification temperature exceeds 850 °C due to increased oxidation of light hydrocarbons. Moreover, the study highlights the influence of grate moving speed on residence time and reaction completeness, which are critical for optimizing syngas yield and quality. The findings demonstrate that while the maximum energy conversion efficiency of the moving-grate system is lower than other reactor types, its lower capital and operating costs, due to the lack of dedicated feedstock pretreatment, make it a viable option for small-scale and pilot-scale applications. This study provides valuable insights into optimizing MSW gasification processes and underscores the potential of the moving-grate furnace for adaptable and cost-effective WtE applications. The novelty of this work lies in the comprehensive evaluation of the moving-grate gasification process under varied operating conditions, providing a foundation for future research on improving efficiency and reducing environmental impact in large-scale MSW management. • The MSW gasification technique has been well geared to the pilot-scale moving-grate furnace. • The comparative performance under MSW combustion and gasification regime is analyzed. • The test data are compared to estimate the adaptability and versatility of gasification technique. • The impacts of critical operating parameters on gasification process are comprehensively discussed. [ABSTRACT FROM AUTHOR]

Abstract Developing advanced electrode materials and understanding their reaction mechanisms are two crucial issues for development of high-performance sodium ion batteries (SIBs). Herein, we synthesized a bimetallic single-phase nanoporous (NP) SnSb alloy with a bicontinuous ligament-channel structure through elaborate design of ternary Mg-Sn-Sb precursor and chemical dealloying. As an anode for SIBs, the NP-SnSb alloy delivers high specific capacity, excellent cycling stability (506.6 mAh g−1 after 100 cycles at 0.2 A g−1; 457.9 mAh g−1 after 150 cycles at 1.0 A g−1) and superior rate capability (458.2 mAh g−1 at 10 A g−1). Moreover, the Na 3 V 2 (PO 4) 3 (cathode)/NP-SnSb (anode) full cell also exhibits outstanding electrochemical performance (cycling stability and rate capability). The unique nanoporous structure (with ligaments of 38.9 ± 7.3 nm), the alloying effect and the synergetic reaction of Sn/Sb account for the eminent electrochemical properties of NP-SnSb. Most importantly, the Na storage mechanism of SnSb alloy was revealed using operando X-ray diffraction and density functional theory calculations. Rather than separate reactions of Sn and Sb, the reaction of SnSb alloy proceeds through a synergetic sodiation/desodiation process via the mechanism: SnSb (crystalline) ↔ Na(Sn,Sb) (amorphous) ↔ Na 9 (Sn,Sb) 4 (amorphous/low-crystalline) ↔ Na 15 (Sn,Sb) 4 (crystalline). Graphical abstract fx1 Highlights • Nanoporous SnSb (NP-SnSb) alloy was fabricated by a facile dealloying strategy. • NP-SnSb anode exhibits good cycling stability and superior rate capability. • A unique Na storage mechanism of SnSb anode was revealed by operando XRD and DFT. • Ex-situ XRD verified the metastable feature of sodiated products of SnSb. [ABSTRACT FROM AUTHOR]

Understanding the sodium (Na) chemistry is crucial for development of high-performance sodium ion batteries (SIBs). Nanostructured bismuth (Bi) has shown great potentials as an anode in SIBs, however, the Na storage mechanisms of Bi are still unclear. Herein, the operando X-ray diffraction (XRD) technique was utilized to probe the Na storage mechanisms of three Bi anodes (sputtered Bi film, nanoporous Bi and commercial Bi). Despite different morphologies and sizes, all the Bi anodes follow the same two-step reversible alloying/dealloying mechanisms (Bi ↔ NaBi ↔ Na 3 Bi) during the discharge/charge processes, associated with two voltage plateaus. As for the intercalation/deintercalation mechanism proposed for nanostructured Bi anodes in SIBs, we rationalize the reason why only the Bi phase is detected in the discharged/charged samples under ex-situ XRD conditions through addressing the stability issue of the Na-Bi system (NaBi and Na 3 Bi). [ABSTRACT FROM AUTHOR]

Due to high efficiency, energy saving, environmental friendliness and safety, the air source heat pump (ASHP) has drawn much attention in the cold and serve cold climate areas of China. In recent years, the Chinese governments further promote the application of air source heat pump in the cold and server area in order to reduce conventional energy consumption and haze occurrence frequency in heating season. The outdoor air temperature is low and fluctuates greatly in these areas, which might lead to unstable running, low efficiency and frequent frost. In this paper, the development direction of ASHP in cold and serve cold was pointed out by analyzing the existing problems of air source heat pump under low temperature condition. These results could provide some references for promotion and application of ASHP in cold and serve cold area like Qinghai province. [ABSTRACT FROM AUTHOR]

Magnetite (Fe 3 O 4) has become a potential anode material in lithium ion batteries (LIBs) because of its high theoretical capacity and low cost, but is impeded for application by its low conductivity and large volume change during cycling. Herein, the Fe 3 O 4 @C-500 composite was fabricated via the one-step pyrolytic carbonization of commercial ammonium ferric citrate (AFC), which is simple and environmentally friendly. As an anode in LIBs, the Fe 3 O 4 @C-500 electrode shows superior specific capacity, long cycling stability and excellent rate performance. Such remarkable performance can be attributed to the formation of the architecture with carbon (C) matrix, not only buffering the volume change and inhibiting the aggregation of internal Fe 3 O 4 nanoparticles during (de)lithiation, but also elevating the electron conductivity. In situ X-ray diffraction (XRD) results demonstrate that the (de)lithiated mechanism of the Fe 3 O 4 @C-500 electrode involves a full electrochemically-driven amorphization upon cycling. Furthermore, the full cell assembled with Fe 3 O 4 @C-500 and LiFePO 4 (LFP) electrodes shows outstanding electrochemical performance, demonstrating its practical energy storage application. [Display omitted] • Fe 3 O 4 @C-500 was fabricated via one-step pyrolytic carbonization of AFC. • Fe 3 O 4 @C-500 delivers good performance by nanoengineering, C matrix and amorphization. • The (de)lithiated mechanism of Fe 3 O 4 @C-500 electrode was probed by in situ XRD. • The full cell presents excellent electrochemical performances. [ABSTRACT FROM AUTHOR]

This research focuses on investigating the air-gasification process of pine sawdust using a fluidized bed unit with Ni/olivine as an in-situ tar destruction catalyst. The goal is to eliminate tar production and obtain high-quality synthesis gas. Consequently, the effects of reaction conditions and catalyst properties on the producer gas composition, the lower heating value (LHV) of the yielded synthesis gas (syngas), char conversion efficiency (CCE), and cold gas efficiency (GE) are comprehensively explored. The conclusions indicate that higher temperatures favor the H 2 and CO production and result in an evident decrease of CH 4 and C 2 H 4 , which is responsible for the increasing gas LHV. The tar capture efficiency (TCE) increases by increasing the equivalence ratio (ER); however, a reverse trend obtains for gas LHV because of a significant decline in the combustible gas contents. The results also reveal that when using Ni/olivine as the bed material, GE reaches an optimum value of 72.4% at equivalence ratio (ER) of 0.21 and then lowers down with a further increase in ER to 0.39 due to the enhanced char combustion reaction. The tar yield (1.3–6.8 g/Nm3) significantly decreases with temperature, whereas H 2 concentration (14.1–29.8 vol %), CCE (51.3–89.1%), GE (44.8–86.1%) and gas LHV (5.13–7.19 MJ/Nm3) promote at high temperature. Compared to raw-olivine, the lower heating value (LHV) of the producer gas slightly increases under the same conditions (T = 800 °C and ER = 0.21) when the bed material is Ni/olivine. The conclusions obtained help to provide reliable theoretical guidance for operating condition optimization of biomass catalytic air-gasification with Ni/olivine as bed material in a fluidized bed reactor. • Ni/olivine catalyst proposed to be employed for catalytic tar destruction during air-gasification of biomass. • Effects of Ni/olivine and operating variables on gas composition and performances were studied. • Ni/olivine showed superior catalytic performance than raw-olivine in terms of tar destruction. • The raw-olivine had a specific catalytic effect for tar elimination and gas production under given condition. [ABSTRACT FROM AUTHOR]

This paper proposes a hybrid intelligent method for multi-fault detection of rotating machinery, in which three methods, i.e. including the redundant second generation wavelet package transform (RSGWPT), the kernel principal component analysis (KPCA) and the twin support vector machine (TWSVM), are combined. Firstly, RSGWPT is used to extract feature vectors from representative statistical characteristics in the decomposition frequency band, and then the KPCA in the feature space is performed to reduce the dimension of features and to extract the dominant features for the following classification. Finally, a novel support vector machine, called twin support vector machine is used to construct a multi-class classifier. Inputting superior features to this classifier, the condition of the monitored machine component can be determined. Experimental results demonstrate that the proposed hybrid method is effective for multi-fault detection of rotating machinery. The TWSVM is also indicated that has better classification performance and faster convergence speed than the normal SVM. [ABSTRACT FROM AUTHOR]

Introduction The aim of this study was to determine how sensitive dental specialists and laypeople are to maxillary incisor crowding when viewed from the front. Methods Computer technology was used to create a series of photographs of the incisors of a smiling woman viewed from the front. The photographs showed varying degrees of maxillary incisor crowding classified according to Little's irregularity index (LII). The incisors illustrated in the photos were ranked on a scale from perfect alignment to severely crowded. The rating was done by 4 groups of people: orthodontists, general dentists, laypeople with experience of orthodontic treatment, and laypeople with no history of orthodontic treatment. Results The orthodontists and the general dentists noted misalignment of 1 central incisor when the LII reached 1.5 mm, whereas the laypeople with or without experience of orthodontic treatment were sensitive to 2.0 mm of crowding. When the LII reached 2.0 mm for 1 lateral incisor, it triggered the orthodontists to consider providing orthodontic treatment, whereas this degree of irregularity was ignored by the general dentists and laypeople. When both central incisors were misaligned, the orthodontists were sensitive to the fact at 2.0 mm of LII, whereas the general dentists and the laypeople with experience of orthodontic treatment became sensitive at 3.0 mm of LII, and the laypeople with no history of orthodontic treatment were sensitive at 4.0 mm of LII. When both lateral incisors were misaligned, the orthodontists noted the crowding at an LII of 3.0 mm, the general dentists became sensitive at an LII of 4.0 mm, whereas both the laypeople with experience of orthodontic treatment and the laypeople with no history of orthodontic treatment ignored it. When the crowding of all maxillary incisors reached an LII of 4 mm, both the orthodontists and the general dentists were alerted to the fact, but both the laypeople with experience of orthodontic treatment and the laypeople with no history of orthodontic treatment were sensitive only to a total incisor crowding equal to an LII of 6.0 mm. Conclusions Orthodontists are more critical than other groups when evaluating the misalignment of the maxillary incisors. It appears that the central incisors play a more important role than do the lateral incisors when dental crowding impacts smile esthetics. For all observer groups, it also appears that people are more sensitive to the misalignment of a single tooth than they are to the same level of crowding distributed over multiple teeth. [ABSTRACT FROM AUTHOR]

• Nanoporous NiSb (np-NiSb) alloy was fabricated by a facile dealloying strategy. • The np-NiSb anode exhibits good cycling stability and superior rate capability. • Operando XRD reveals the sodiation/desodiation mechanism of the np-NiSb anode. • On-line DEMS verifies the gas release of half cells with NiSb anode during cycling. Engineering Sb-based anode materials is the key to enhance their electrochemical performance for sodium ion batteries (SIBs) by solving the issues of the rapid capacity decay and poor rate capability. In this work, a nanoporous NiSb alloy (np-NiSb) with a three-dimensionally interconnected ligament-channel structure was synthesized by a facile dealloying strategy. As an anode for SIBs, the np-NiSb alloy exhibits excellent cycling performance, rate capability and stability with a reversible capacity of 334.6 mAh g −1 at 0.2 A g −1 after 100 cycles, 155.6 mAh g −1 at 20 A g −1 and a capacity retention rate of 97% after 100 cycles at 1 A g −1. The nanoporous structure and the introduction of inactive Ni effectively tolerate the dramatic volume changes during the charge/discharge processes, restraining the pulverization of np-NiSb. The unique ligament-channel network structure with an average size of about 30 nm significantly shortens the ion transmission distance, ensuring the fast charge transfer at high rates. Operando X-ray diffraction reveals the sodiation/desodiation mechanism of the np-NiSb anode during the discharge/charge processes. In addition, on-line differential electrochemical mass spectrometry further explores the reaction mechanism of np-NiSb. This work highlights constructing nanoporous Sb-based alloys as an effective strategy to improve the performance of SIBs. [Display omitted] As an anode for SIBs, the np-NiSb alloy with bicontinuous ligament-channel structure exhibits good cycling stability with capacity retention rate of 97% over 100 cycles at 1 A g −1 (279.7 mAh g −1). [ABSTRACT FROM AUTHOR]

• MnO/Mn 3 O 4 –600 anode was synthesized through a one-step pyrolysis of MOD. • The MnO/Mn 3 O 4 –600 anode shows structure-related performance towards li storage. • The (de)lithiated mechanism of MnO/Mn 3 O 4 –600 was probed by in situ XRD. • The LFP||MnO/Mn 3 O 4 –600 full cell shows outstanding electrochemical performance. Manganese oxides are considered a highly promising anode material in lithium ion batteries (LIBs) because of their high theoretical capacity, abundant sources, relatively low voltage hysteresis, nontoxic and cost-effectiveness. Nevertheless, the practical application of these materials faces many challenges such as poor lifespan and serious volume variation during operation. Herein, MnO/Mn 3 O 4 –600 composite was obtained based on a single-step pyrolysis procedure from commercial manganese(II) oxalate dihydrate (MOD, C 2 H 4 MnO 6). The MnO/Mn 3 O 4 –600 anode exhibits an exceptionally high reversible capacity of 1041.8 mAh g −1 at the current density of 200 mA g −1, and a remarkable lifespan at 1000 mA g −1. The outstanding performance benefits from the formation of porous structures on nanoparticles, which not only mitigate volume changes and prevent the aggregation of internal MnO/Mn 3 O 4 nanoparticles, but also enhance the ion diffusion. The in-depth insights into the (de)lithiated mechanism of the electrode are investigated by in situ X-ray diffraction (XRD) technique. Moreover, when applied in a full cell, the MnO/Mn 3 O 4 –600 anode demonstrates exceptional electrochemical property. The MnO/Mn 3 O 4 –600 was synthesized through a single-step pyrolysis process of commercial manganese(II) oxalate dihydrate. As the anode in LIBs, MnO/Mn 3 O 4 –600 demonstrates excellent performance, which can be attributed to the nanoengineering of MnO/Mn 3 O 4 nanoparticles and the porous architecture. (De)lithiated mechanism was proposed by in situ XRD. Moreover, the LFP||MnO/Mn 3 O 4 –600 full cell exhibits good electrochemical performances. [Display omitted] [ABSTRACT FROM AUTHOR]

Alloy-type anodes have attracted extensive attention in magnesium-ion batteries (MIBs) due to their low reaction potentials and high theoretical specific capacities. However, the kinetically sluggish Mg insertion/extraction and diffusion in electrode materials, as well as the huge volume changes resulting in the capacity decay limit their further development. Herein, a series of porous-Bi (P-Bi x) anodes are fabricated through a facile dealloying strategy based on the Sn 100-x Bi x (x = 1, 5, 10, 43, at.%) precursor alloys. Among them, the P–Bi 10 anode delivers a high discharge specific capacity (376.0 mAh g−1 at 500 mA g−1), greatly improved rate capability (363.3 mAh g−1 at 1000 mA g−1) and good cycling stability even at 2000 mA g−1 (104.0 mAh g−1 after 1000 cycles). Furthermore, operando X-ray diffraction (XRD) is performed to unveil the magnesiation/demagnesiation mechanisms of the P–Bi 5 and P–Bi 10 anodes, indicating a simple two-phase reaction process. Additionally, the P–Bi 10 anode displays good compatibility with conventional Mg salt electrolytes such as Mg(TFSI) 2. Our findings could provide useful information on design of high-performance alloy-type anode materials for MIBs. [Display omitted] • P-Bi x anodes were facilely fabricated through dealloying of Sn 100-x Bi x precursors. • The P–Bi 10 shows superior Mg storage performance and compatibility with Mg(TFSI) 2. • Operando XRD unveiled a simple two-phase reaction between Bi and Mg 3 Bi 2. [ABSTRACT FROM AUTHOR]

For lithium ion batteries (LIBs), low electronic conductivity of CuO leads to rapid capacity decay and poor structural stability. Herein, we successfully fabricate three-dimensional CuO nanoflake arrays coated Cu foam by facile and efficient electrochemical oxidation. When being applied as anode material for LIBs, the CuO electrodes deliver stable reversible capacities of 523.9 mA h g −1 at 0.5 A g −1 , 376.1 mA h g −1 at 1.0 A g −1 and 322.7 mA h g −1 at 2.0 A g −1 with high coulombic efficiency (>99%) after 100 cycles. A long cycle life of up to 400 cycles at 2.0 A g −1 is also achieved with the retention capacity of 193.5 mA h g −1 . Moreover, the electrode exhibits excellent rate capability and can regain its original capacities as reversing to the low current densities. Noticeably, on-line differential electrochemical mass spectrometry and in situ Raman measurements confirm the formation of solid electrolyte interface film and the conversion mechanism for the CuO electrodes, respectively. The superior lithium storage performance can be attributed to the favorable nanoflake structures with high surface area and the perfect electrical contact between CuO and Cu substrate. [ABSTRACT FROM AUTHOR]

To cope with the low energy efficiency issue caused by load difference between multiple actuators in the load sensing (LS) system, a hybrid distributed-centralized load sensing (HDC-LS) system is proposed in this study for electrified construction machinery. The idea is to establish a hybrid distributed-centralized actuator (HDCA) by connecting a distributed actuator and the original hydraulic cylinder (called centralized actuator) parallelly to balance load difference. Two types of actuators are considered for the distributed actuator: electro-hydrostatic actuator (EHA) and electro-mechanical actuator (EMA). A torque controller of the motor is proposed for the distributed actuator to reduce the energy loss of the pressure compensator and recover the potential energy. Moreover, a design criterion is established to determine the main parameters of the distributed actuator and redesign the control valve of the centralized actuator. A simulation model with a 6 T excavator is established to validate the proposed system. Compared with the traditional LS system, the results show that the energy consumption of the battery is reduced by 11.4 % using EHA as the distributed actuator and reduced by 13.6 % using EMA. Meanwhile, the motion performance of the proposed system is consistent with that of the traditional LS system. The proposed system is beneficial for reducing the energy consumption and battery capacity of electrified construction machinery. • Hybrid distributed-centralized load sensing system is proposed for construction machinery. • The proposed system can reduce energy consumption and battery capacity. • A motor torque controller is designed for load balance between multiple actuators. • A parameter determination criterion is established for the design of the new system. [ABSTRACT FROM AUTHOR]

• A method for obtaining the single-track characterization model by substituting the morphological parameters into the Gaussian function is proposed. • The concept of the ratio F/O of the area between the filled area and the overlapping area is proposed. • The top-tangent overlapping model was developed based on single-track characterization model and multi-track forming characteristics. As an important characterization of surface quality, the surface morphology of laser cladding coating directly affects the choice and difficulty of subsequent processing technology. The laser cladding coating is made of multi-track cladding layers, and the variation and optimization of overlap rate directly affect the quality of surface morphology. Firstly, the height, width and wetting angle of single-track cladding layer are substituted into the Gaussian function to obtain the characterization curve of single-track cladding layer, which can accurately characterize the profile curve of the single-track cladding layer. Then, by analyzing dual-track overlapping experiments with the varied overlap rates, it was found that the contour of the filled area is approximately a quadratic function curve. The area ratio of the filled area to the overlapping area first decreases and then increases with the increase of the overlap rate, reaching about 0.5 near the optimal overlap rate. Finally, a top-tangent overlapping model is developed based on the single-track characterization model of the Gaussian function and the forming characteristics of multi-track cladding layers. Experimental results show that the model can well characterize the multi-track cladding layers, and it is of great significance for optimizing the overlap rate of laser cladding and obtaining high-quality cladding layers. [ABSTRACT FROM AUTHOR]

Artificial ribs interrupting the viscous sublayer beneath the absorbing plate are used to enhance SAH heat efficiency. In the present study, the CFD-adjoint reverse design method is developed to intelligently design the rib profile. Based on the zero-order CFD solution, the shape sensitivity of the rib profile is calculated by the CFD-adjoint solver, which identifies the profile characteristics to improve thermo-hydraulic performance (THPP). According to the shape sensitivity, the reverse design is conducted with geometrical constraints, optimization algorithms, and mesh deformation. To maximize THPP , five novel ribs are reversely designed under Reynolds numbers ranging from 4000 to 16000. The flow and heat transfer characteristics of the reversely designed ribs indicate the CFD-adjoint reverse design is in accord with the theory that turbulence enhances heat transfer in the boundary layer. The Nusselt number of the novel ribs is averagely 1.9 times compared with the smooth. The THPP of the novel ribs approaches the local maximum at the design Reynolds number with the average THPP of 1.51. [ABSTRACT FROM AUTHOR]

Particles enter the lubrication interface during operation of water lubricated stern bearings (WSB). This will affect the service performance. The mechanism of particle dynamics effect is not yet clear. This paper establishes novel fluid-structure coupling lubrication model of bearings with particle-dynamic effect. The relationship between liquid-film lubrication performance and particle-dynamic effect is clarified. The variation and influence rules of lubrication performance of bearings under different working conditions is specified. The interaction mechanism between particles and load-carrying performance is revealed. Theoretical analyses are consistent well with test, that verifies correctness and rationality of model and algorithm. Research is of great significance for the optimal design for such bearings under the service condition of heavy sediment. [Display omitted] • The two-way fluid-structure coupling models with particle-dynamic effects are put forward. • The lubrication performances considering particle-dynamic effects are analyzed. • The variation and influence rules of lubrication performance under different working conditions are specified. • The interaction mechanism between particles and load-carrying performance is revealed. [ABSTRACT FROM AUTHOR]

This study investigates a solid chemisorption energy storage system utilizing a multi-component chloride salt composite adsorbent with a mass ratio of NH 4 Cl, CaCl 2 , MnCl 2 , and expanded natural graphite treated with sulfuric acid (ENG-TSA). The system features a shell-and-tube heat exchanger and analyzes refrigeration and heat storage performance under varying industrial low-temperature waste heat (60–110 °C) conditions, with condensation and evaporation temperatures of 0–25 °C and discharging temperatures of 40–60 °C. The results indicate that the multi-salt composite adsorbent reduces hysteresis between adsorption and desorption stages. The highest coefficient of performance (COP) and specific cooling power (SCP) were 0.461 and 328 W/kg, respectively, at an evaporation temperature of 25 °C and a charging temperature of 110 °C. Excessively long cycle times negatively affect system efficiency, with optimal performance achieved at a 40-min cycle. The findings highlight the system's effectiveness for industrial low-grade waste heat recovery, providing a solid foundation for future reactor design and material selection. • A chemisorption energy storage system utilized for industrial waste heat recovery was constructed. • The shell-and-tube heat exchanger-type adsorption bed reactor incorporated with tri-salt composite adsorbent was designed. • The refrigeration and heat storage performance under various conditions were comprehensively explored and analyzed. • The system built extended the application scope of chemisorption energy storage method. [ABSTRACT FROM AUTHOR]

It is well known that lumped masses can change the frequency characteristics of the structural system, and aeroelastic flutter happens due to the coalescence of two modes. Therefore, it can be expected to improve the aeroelastic stability by the lumped mass. This paper studies the influence mechanism of the lumped mass on the aeroelastic behaviors of two-dimensional (2D) panels in supersonic airflow, and proposes an axially functionally graded design method using the lumped mass. In this investigation, the finite element method (FEM) is used to formulate the aeroelastic equation of motion for the panels with the lumped mass and spring constraint. For 2D panels with the lumped mass, the local mode coalescence is observed, and the influences of the weight and location of the lumped mass on the flutter stability and their mechanism are analyzed. The optimal ranges for the weight and location of the lumped mass are given out. For 2D panels with the spring constraint, the sudden decrease of the flutter bound due to the mode veering are analyzed, and an effective method to eliminate it by using the lumped mass is proposed. Finally, a structural optimization method based on the axially functionally graded design is proposed. [ABSTRACT FROM AUTHOR]

• Effect of passive heating renovation on energy poverty alleviation was verified. • Coal consumption and thermal comfort were measured and compared respectively. • Air tightness, thermal defect and indoor air quality were measured and evaluated. • Potential of the passive heating renovation was explored and further optimized. • Affiliated issues for alleviating energy poverty in policy, technology, etc. were discussed. Energy poverty refers to a situation that people cannot access and use energy safely. It is a major challenge for the global energy system because of its negative impacts on household income, health, education, gender equality and environmental conditions. To solve this problem, many countries advocate the development and promotion of passive solar technology, but the effectiveness of them for energy poverty mitigation has not been evidenced. Therefore, based on empirical studies in the rural areas of Qinghai-Tibet Plateau, this paper aims at investigating the effectiveness of passive solar heating renovation to alleviate energy poverty in rural plateau areas. Specifically, this paper compared and analyzed the coal consumption and indoor air quality during the heating period before and after the renovation of a single-storey building. Further, based on the IES-VE numerical simulation, this paper analyzed the impact of building envelope structure performance on indoor air temperature. The results show that after building renovation, the coal consumption during the heating period could be reduced by 97 kg/week, while the indoor average temperature of two bedrooms were increased by 4.8 °C and 1.7 °C respectively. Setting up the coal stove as an auxiliary heating device, can alleviate the defects of insufficient heating of passive solar energy technology, and indoor temperature could be further improved. However, indoor air quality was lowered because of the high PM 2.5 concentration. In contrast, improving envelope performance could further improve the average temperature of two bedrooms and the sunspace to 16.7 °C, 15.9 °C and 15.6 °C, meeting the requirements of indoor space heating. In general, passive solar heating could achieve satisfactory results, but to alleviate energy poverty effectively in rural plateau areas, further attention should be paid to other technical, economic, social and policy issues. [ABSTRACT FROM AUTHOR]

Solar heating should be recommended strongly for domestic buildings in the Qinghai–Tibetan plateau due to the area's high intensity radiation. In this paper, a novel hybrid solar heating system is presented, that includes a solar kang system, a Trombe wall and a direct gain window. The effects of five combined solar heating operation modes on the indoor hourly temperature for one case domestic building located in the Qinghai–Tibetan plateau were investigated by field measurement and numerical simulation. The optimal operation mode for improving the indoor thermal environment was determined. Furthermore, the effectiveness of each operational mode on the east room was quantitatively evaluated and ranked. The results show that the numerical simulation and field experimental results were well agreed, although there were some differences in specific values. In addition, the results it indicated that a solar kang running all days and Trombe wall running daytime played a significant role in improving the indoor thermal temperature. These relevant findings could provide a reference for solar heating system design and indoor thermal comfort improvement for rural domestic buildings in the Qinghai–Tibetan plateau. [ABSTRACT FROM AUTHOR]

Development of excellent bi-functional electrocatalysts for both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) remains a key issue for the commercialization of various electrochemical devices such as fuel cells and metal-air batteries. Herein, we report the synthesis and electrocatalytic performance of mesoporous nanostructured spinel-type MFe 2 O 4 (M = Co, Mn, Ni) oxides which can serve as alternative low-cost bi-functional electrocatalysts for ORR/OER. Loaded on XC-72 carbon support, the MFe 2 O 4 spinel oxides show the M-dependent catalytic activities with CoFe 2 O 4 being the most active electrocatalyst followed by MnFe 2 O 4 and NiFe 2 O 4 for ORR. For the OER, however, the activity increases in the order: MnFe 2 O 4 < NiFe 2 O 4 ≈ CoFe 2 O 4 . Additionally, the CoFe 2 O 4 catalyst shows the smallest overpotential between ORR and OER. Compared with commercial IrO 2 , the MFe 2 O 4 catalysts reveal comparable OER activities. Furthermore, the MFe 2 O 4 catalysts exhibit much better methanol tolerance and stability than Pt/C. Meanwhile, both electrochemical measurements and density functional theory (DFT) calculations verify that the ORRs on the MFe 2 O 4 catalysts are a direct 4 e − pathway in the alkaline solution, and expound the reason for the excellent methanol tolerance of MFe 2 O 4 . [ABSTRACT FROM AUTHOR]

Metallic actuators have attracted a great deal of attention owing to their potential advantages over piezoelectric ceramics and conducting polymers. Here, we report different electrochemical actuation behaviors of bulk nanoporous palladium (np-Pd) fabricated by dealloying in acid (0.5 M H 2 SO 4 ) and alkaline (1.0 M KOH) solutions. In the 1.0 M KOH solution, the reversible expansion/contraction of np-Pd well responds to the adsorption/desorption of involved species (H and OH). In the 0.5 M H 2 SO 4 solution, only continuous contraction can be observed in the potential region involving the H-adsorption/desorption, but the reversible strain appears in the potential region related to the OH-adsorption/desorption. Moreover, the surface stress-charge coefficient (ξ) exhibits inverse signs associated with the H-adsorption (absorption)/desorption and OH-adsorption/desorption in the alkaline solution. More importantly, the reversible strain amplitude of np-Pd can be regulated by changing the potential scan rate or by being stimulated in different electrolytes. [ABSTRACT FROM AUTHOR]

Microstructural and compositional evolution of nanoporous silver (NPS) during dealloying of rapidly solidified Mg 65 Ag 35 alloy in the 1 wt% HCl solution has been investigated using X-ray diffraction, scanning electron microscopy, transmission electron microscopy and energy dispersive X-ray analysis. The amount of MgAg phase decreases and that of f.c.c. Ag increases with increasing dealloying time, and no intermediate phase occurs during dealloying. The residual Mg content in NPS decreases with increasing dealloying time, following an exponential decay formula. The coarsening of ligaments in NPS with dealloying time follows a nonlinear relationship, and the coarsening exponent ( n ) is ∼4.8 for the dealloying of Mg 65 Ag 35 . In addition, the activation energy is 55.7 ± 2.9 kJ mol −1 for the chemical dealloying of the rapidly solidified Mg 65 Ag 35 alloy in the HCl solution. [ABSTRACT FROM AUTHOR]

• The failure mode of large-flow valve is different from that of small-flow valve. • Rotation and impact are the key factors of wear failure of large flow valve plate. • The failure of the valve plate is the mixed wear dominated by adhesive wear. • The improved valve plate materials obviously reduce the wear of sealing surface. The failure mechanism of suction valve in high pressure and large flow water hydraulic plunger pump used in coal mine is studied. Previous studies believe that in traditional plunger pump with low pressure and small flow, the impact caused by the dynamic contact between the valve plate and the valve seat is the main reason for the performance deterioration of suction valve. However, in the practical use of high-pressure and large-flow hydraulic plunger pump, it is found that there are signs of rotating wear and material loss on the sealing surface of the suction valve plate. In order to explain the premature failure of the valve, the mathematical model of the force and movement of the valve plate during the suction process of the high-pressure and large-flow hydraulic plunger pump is established. Three-dimensional computational fluid dynamics (CFD) method and nonlinear finite element method are used to numerically analyze the operation process and dangerous conditions of the valve plate. The results show that under the action of the uneven flow field, the combination effects of low speed rotation and heavy load during closing process is the key factor causing material loss. According to the microstructure and elemental composition of the worn surface, the specific wear failure mechanism is determined, and the effectiveness of the numerical method is verified. Finally, the improved valve plate materials are proposed. The field test of high pressure and large flow pump proves that the wear of the valve plate is significantly reduced after the improvement. [ABSTRACT FROM AUTHOR]

Hybrid porous tilting pad bearing (HPTPB) is a new hybrid lubrication bearing showing potential for oil-free high-speed turbomachinery with reliable stability. This study presents a thermo-hybrid lubrication FSI-CFD model for HPTPB static characteristics. The interaction between the gas lubrication and the adaptive pad motion is solved with dynamic mesh iterative algorithm. The influences of rotor speed, supply pressure, radial stiffness, tilting stiffness, and nominal clearance on the load capacity, mass leakage, friction torque, and temperature rise are investigated. The adaptive pad motions significantly influence the hybrid lubrication of the hydrostatic and hydrodynamic effects in the HPTPB. With the complex bearing configuration, the static performances of HPTPB depend on the combined effect of the design parameters. • Hybrid porous tilting pad bearings draw attention to the potential of friction-free and oil-free transport in machines. • Thermo-hybrid lubrication FSI-CFD model is developed to study the static characteristics of porous tilting pad bearings. • Effect of rotor speed, supply pressure, stiffness, and clearance on the pad motion and the static performance of the bearing. • Influences of the adaptive pad motions on the hybrid lubrication of the hydrostatic and hydrodynamic effects. • The load capacity of the bearing is in the opposite direction to the rotor eccentricity, with the pad tilting motion. [ABSTRACT FROM AUTHOR]

To promote the application of renewable energy in low-energy buildings in Alpine regions, a solar-air source heat pump (SASHP) system was investigated based on a low-energy residential building in Xining City. First, a solar fresh air (SFA) heating system simulation model was established in TRNSYS software, and the reliability of the model was verified with measured values. In addition, based on the SFA heating system model, a SASHP system model was further realized. The operating characteristics of the SASHP system were explored in depth and compared with those of the single-ASHP system in the heating season. The results show that the SFA heating system model is reliable, with relative errors that can be controlled within 15%. The indoor average temperature (T ave) can be maintained from 16.13 to 19.61 °C. The SASHP system can leads to T ave fluctuations within the range of 21.4–22.9 °C, and the solar fraction can reach 55% in the heating season. Furthermore, the SASHP system can reduce energy consumption by 55.38% compared to the ASHP system; additionally, the COP of the SASHP system is 109.43% higher than that of the ASHP system, and the annual cost is 9.7% lower. Moreover, the SASHP system produces 55.48% less carbon emissions than the ASHP system. These results provide guidance for the application of SASHP systems in Alpine regions. [ABSTRACT FROM AUTHOR]

Tin (Sn)-based anodes attract extensive attention for magnesium ion batteries however challenges and issues exist, such as relatively difficult alloying reaction, sluggish diffusion kinetics and rapid capacity decay. Herein, we introduce a second phase of bismuth (Bi) with varying contents into Sn via magnetron co-sputtering and get insight into how the Bi introduction boosts the electrochemical reactivity of Sn through experimental and density functional theory (DFT) calculations. The experimental results reveal that the introduction of Bi can effectively trigger the alloying reaction of Sn with Mg and the further increasing of Bi significantly improves the electrochemical performance of Sn–Bi electrodes. Moreover, the activated function of introducing the Bi phase into Sn is found in the bulk rolled Sn–Bi system. The DFT calculations demonstrate that the introduction of Bi into Sn obviously lowers the defect formation energy of Mg insertion in Sn, which further rationalizes the experimental results. Additionally, operando X-ray diffraction is performed to probe the activation process and magnesiation/demagnesiation mechanisms of the Sn–Bi electrode. The activation mechanism of Bi on Sn alloying with Mg is discussed, considering the function of second phase, the influence of Bi solid solution, as well as the size effect. Image 1 • The Sn–Bi films were designed to improve reaction activity of Sn for MIBs. • The introduction of Bi triggers alloying reaction of Sn with Mg experimentally. • The DFT calculations further rationalizes the experimental results. • The influence of size effect might not be the decisive factor for Sn in MIBs. [ABSTRACT FROM AUTHOR]

The low capacity of traditional graphite (372 mAh g−1) greatly limits its development as electrode material for future applications, and seeking new anode material is becoming extremely urgent in order to meet the increasing demands. In this work, flexible, self-supporting CuGa 2 films are fabricated by simply painting liquid Ga onto commercial Cu films, which can be used as electrodes directly after annealing. When the CuGa 2 films are applied as anodes in lithium ion batteries, higher capacity (more than 630 mAh g−1 at a current density of 200 mA g−1) and better rate performance (463.7 mAh g−1 at 4000 mA g−1) are achieved compared with those with pure Ga electrodes. Meanwhile, the lithiation-delithiation mechanism is detected by in-situ X-ray diffraction, and the alloying-dealloying processes (CuGa 2 + 2 x Li+ + 2 x e− ↔ Cu + 2Li x Ga) can be verified at the first and fourth cycles. The CuGa 2 anode shows excellent self-healing properties during cycling. Image 1 ∙ A simple, maneuverable method was developed to fabricate CuGa 2 films. ∙ The flexible, self-supporting CuGa 2 films can be used as anodes for LIBs directly. ∙ The CuGa 2 anode exhibits excellent electrochemical performance. ∙ The SEM and in-situ XRD verify the self-healing behaviors of the CuGa 2 anode. [ABSTRACT FROM AUTHOR]