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In the face of global climate change and the need for energy diversification, electrocatalytic technology emerges as an eco‐friendly solution. However, persistent electrode failures hinder long‐term stability. This review comprehensively outlines the primary causes leading to the failure of self‐supported electrodes, encompassing substrate passivation, substrate/catalyst dissolution, CO poisoning, catalyst migration and agglomeration, as well as cathodic etching. Proposed strategies center on material design, emphasizing anchoring, lattice matching, substrate stability, and morphological control. Advanced characterization techniques and in situ technologies offer promising ways. The integrated deployment of these strategies will provide crucial guidance and support for the sustainable advancement of electrocatalytic technology. [ABSTRACT FROM AUTHOR]

The electrocatalytic selective oxidation of 5‐hydroxymethylfurfural (HMF) presents a highly efficient and eco‐friendly method for biomass utilization. Herein, we synthesized pure β‐Ni(OH)2 and amorphous Ni(OH)2 on nickel foam (NF) using a facile stepwise electrodeposition technique and evaluated their catalytic performances for the oxidation of HMF to 2,5‐furan dicarboxylic acid (FDCA). The β‐Ni(OH)2 nanosheets‐decorated electrode (β‐NiNS/NF) exhibited excellent interfacial lattice matching with the substrate nickel, resulting in enhanced electron transfer at the catalyst‐substrate interface, as confirmed by electrochemical analysis. Consequently, the β‐NiNS/NF electrode displayed improved intrinsic electrocatalytic activity and interfacial stability. Additionally, it demonstrated effective HMF adsorption capability. These advantageous properties led to enhanced HMF conversion, selectivity, and structural stability. Notably, the β‐NiNS/NF electrode achieved an unprecedented FDCA yield of 80.6 % under relatively large current density galvanostatic electrolysis commonly used in industry. Moreover, our investigation identified a novel possible oxidation pathway during HMF electrocatalysis. This study not only showcases an efficient and scalable synthetic approach but also highlights the potential of the β‐NiNS/NF electrode for industrial HMF electrocatalytic oxidation under conditions involving relatively large applied currents. [ABSTRACT FROM AUTHOR]

Nanofiltration (NF) membranes as high selective separators are appealing for molecular sieving, which still remains a great challenge for the mixed dyes with same charge. In this study, cellulose acetate (CA) membranes were firstly aminated by ethylene imine polymer (PEI), and then the thin film of metal organic frameworks (MOFs) were constructed onto aminated CA membrane through forward-diffusion, slow crystallization and in situ growth of FeCo-Prussian blue (FeCo-PB) crystallization layers. The designed PB@CA composite NF membrane shows an ideal rejection for Congo red (CR)/methyl orange (MO) mixture solution, with 99.7%±0.2% for CR and 33.5%±2% for MO. In addition, the composite NF membrane demonstrated good efficiency for photocatalytic degradation of organic fouling (permeability recovery ratio was up to 92%) due to the active FeCo-PB micro-cubes. Thus, this work provides a practical strategy to prepare MOFs mediated thin film composite nanofiltration membrane for precise molecular sieving and catalytic antifouling performances. [ABSTRACT FROM AUTHOR]

Investigations regarding the relation of noise performance for centrifugal pump operating in pump and turbine modes continue to be inadequate. This paper presents a series of comparisons of flow-induced noise for both operation modes. The interior flow-borne noise and structure modal were verified through experiments. The flow-borne noise was calculated by the acoustic boundary element method (ABEM), and the flow-induced structure noise was obtained by the coupled acoustic boundary element method (ABEM)/structure finite element method (SFEM). The results show that in pump mode, the pressure fluctuation in the volute is comparable to that in the outlet pipe, but in turbine mode, the pressure fluctuation in the impeller is comparable to that in the draft tube. The main frequency of interior flow-borne noise lies at blade passing frequency (BPF) and it shifts to the 9th BPF for interior flow-induced structure noise. The peak values at horizontal plane appear at the 5th BPF, and at axial plane, they get the highest sound pressure level (SPL) at the 8th BPF. Comparing with interior noise, the SPL of exterior flow-induced structure noise is incredibly small. At the 5th BPF, the pump body, cover and suspension show higher SPL in both modes. The outer walls of turbine generate relatively larger SPL than those of the pump. [ABSTRACT FROM AUTHOR]

The variations in the Earth's rotation are important to space dynamic theory and natural disasters because they affect the length-of-day (LOD) and consequently human lives. We use maximum entropy method (MEM), Lomb method (LOMB), and phase dispersion minimization (PDM) to determine the natural periods of equally spaced LOD time series. We transform the observational monthly LOD time series (LODM) to unequally sampled series (LODMD) by removing every fourth, third, and half of the total samples. We also apply spline interpolation to LODMD to yield equally spaced time series (LODMDN). The results suggest that regardless of the time series, the MEM frequency is 0.1660 month−1 and 0.0840 month−1, whereas LOMB and PDM yield 0.166 month−1 and 0.083 month−1, respectively. Furthermore, missing data that are less than half of the total data or spline interpolation do not affect the analysis. For the amplitude, neither missing data nor spline interpolation affect the analysis. [ABSTRACT FROM AUTHOR]

Spindles are among the key parts of rotatory machinery and featured widely in a variety of industrial equipment. Fracture failure of a spindle (caused either by inappropriate design or operation) could lead to significant economic losses or high numbers of casualties. Using data from accidents, caused by spindle fracture in centrifuges in China as an example, this research work systematically investigates the reasons leading to the fracture failure of the spindles in operation. Our methods include analysing the chemical composition, micro-morphology, and mechanical properties of the fractures. Our results show that the spindle failure is due to a form of fatigue fracturing caused by stress concentration and alternative bending stress. A finite element method was additionally utilised to further calculate and analyse the stress distribution over a spindle. It was discovered that the stress is severely concentrated at the transition fillet of the spindle. Finally, we show that the stress distribution in the spindle can be improved by adopting a structure in the form of a conic section and by reducing the eccentric moment. In this way, the fatigue resistance of a spindle can be enhanced. [ABSTRACT FROM AUTHOR]

Due to various errors such as the radial distortion of lenses and perspective distortion in digital images, there are non-linear geometric distortions in such images. Therefore, a new method based on the black-white square array is proposed to calibrate visual measuring systems at a micro-sized measurement scale. Meanwhile, by analysing the sources of error, the binary cubic polynomial model for a curved error surface is established. Thereafter, the sub-pixel coordinates of each edge of the checkerboard calibration board are extracted to obtain the coordinates of corner points, which are regarded as the actual point coordinates. Later, the actual point coordinates are combined with the theoretical point coordinates to establish equations, so as to find the coefficients of the error model through fitting. On this basis, calibration is performed on the backlight visual measuring system at a micro-sized measurement scale. As verified experimentally, the proposed method is endowed with high measurement accuracy and robustness. Meanwhile, characterised by its simple and reliable calibration process, it has been applied in a system used for detecting the aperture and centre distance of the intermediate features in gear pumps. [ABSTRACT FROM AUTHOR]

A supercritical carbon dioxide (ScCO) assisted phase inversion was developed to produce microporous poly(vinylidene fluoride) (PVDF) membranes whose morphology characteristics arise from both liquid-liquid demixing and solid-liquid demixing (crystallization). This result was confirmed by Fourier transform infrared spectroscopy (FTIR), from which both α and β crystals were found. As revealed by contact angle experiment, the PVDF membranes prepared via ScCO assisted phase inversion were more hydrophobic compared with the control membrane produced via conventional immersion-precipitation technique. In particular, the sample with 15 wt% PVDF prepared at 45 °C and 13 MPa exhibited a contact angle of 142°, which was mainly caused by the multilevel micro- and nano-structure. The effects of polyethylene glycol (PEG), polyvinyl pyrrolidone (PVP) and lithium chloride (LiCl) on the structures and crystal form were investigated. PVP promoted the formation of α phase crystal form, while PEG boosts the evolution of β phase. LiCl restrained the crystallization degree of PVDF membrane under ScCO. [ABSTRACT FROM AUTHOR]

Under the assumption that µ is a non-doubling measure on ℝ which only satisfies the polynomial growth condition, the authors obtain the boundedness of the multilinear fractional integrals on Morrey spaces, weak-Morrey spaces and Lipschitz spaces associated with µ, which, in the case when µ is the d-dimensional Lebesgue measure, also improve the known results. [ABSTRACT FROM AUTHOR]

Graphics processing units (GPU) have taken an important role in the general purpose computing market in recent years. At present, the common approach to programming GPU units is to write GPU specific code with low level GPU APIs such as CUDA. Although this approach can achieve good performance, it creates serious portability issues as programmers are required to write a specific version of the code for each potential target architecture. This results in high development and maintenance costs. We believe it is desirable to have a programming model which provides source code portability between CPUs and GPUs, as well as different GPUs. This would allow programmers to write one version of the code, which can be compiled and executed on either CPUs or GPUs efficiently without modification. In this paper, we propose MapCG, a MapReduce framework to provide source code level portability between CPUs and GPUs. In contrast to other approaches such as OpenCL, our framework, based on MapReduce, provides a high level programming model and makes programming much easier. We describe the design of MapCG, including the MapReduce-style high-level programming framework and the runtime system on the CPU and GPU. A prototype of the MapCG runtime, supporting multi-core CPUs and NVIDIA GPUs, was implemented. Our experimental results show that this implementation can execute the same source code efficiently on multi-core CPU platforms and GPUs, achieving an average speedup of 1.6 ~ 2.5x over previous implementations of MapReduce on eight commonly used applications. [ABSTRACT FROM AUTHOR]

The effect of electrode configuration on mass transfer rate in a tubular electrochemical reactor was investigated with the limiting-current method. The expression of mass transfer enhancement factor was derived from the dimensionless equations for different electrode configurations. Furthermore, the local velocity distribution in the tubular electrochemical reactor was simulated by computational fluid dynamics technology. These simulation results explained the reason of mass transfer enhancement for mesh electrode: the rotation of the solution is induced by high rates of shear, and small eddies are formed. The local velocity distributions in bulk for X-dimension get flatter because of the lateral momentum transfer. Due to the impact and obstruction of electrode holes, the turbulence of the electrolyte gets drastic and the mass transfer performance in the tubular electrochemical reactor is improved. [ABSTRACT FROM AUTHOR]