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Aiming at the problems that clearance is difficult to modify and operation stability is poor of pinion and rack used in the large machine tool carrier feeding device，the beveloid pinion and rack which can modify clearance axially is proposed.The finite element analysis of the changes of variables such as static transmission error，uniform degree of contact stress，contact force are carried out when considering axial clearance changes.The results show that the influences of axial clearance changes to variables depend on torques directly，the influences when torque is 50 N∙m or 100 N∙m from large to small are in the order of uniform degree of contact stress，static transmission error，contact force.The influences when torque is 200 N∙m or 400 N∙m from large to small are in the order of static transmission error，uniform degree of contact stress，contact force.

As one of the most important parameters in mental cutting, cutting speed has a significant influence on residual stress. Finite element method and experiment method are used to study the relationship between cutting speed and residual stress when orthogonal cutting TC4 titanium alloy. The result of simulation and experiment shows that: when the cutting speed is low, the residual stress in axial direction is compressive stress and gradually converts to tensile stress with the increase of cutting speed, but it will convert to compressive stress again if the cutting speed continues to increase; the residual stress in tangential direction is constant to compressive stress and it will decrease with the increase of cutting speed.

Centrifugal slurry pumps are extensively applied in industrial industries such as power metallurgy, petrochemicals, deep-sea mining, and other industrial fields. The primary objective of this research is to assess how conveying settings and particle characteristics influence the 100SHL4147 slurry pump's collision and erosion properties. Firstly, the computational fluid dynamics–discrete element method (CFD-DEM) coupling model fully coupled particle–fluid co-flow numerical simulation interface is built by utilizing the C++ language and the results are proven with tests. Subsequently, the simulation examines the wear properties of different sections through which the flow passes in the 100SHL4147 centrifugal slurry pump. In addition, following theoretical guidance, the slurry pump impeller's wear resistance performance can be improved by adjusting design factors such as the intake edge location and the blade wrap angle. The results are as follows. It is recommended to replace the impeller promptly due to the findings that indicate that the entire blade's pressure surface is vulnerable to different degrees of erosion under high-concentration situations. When the particle size increased from 0.4 to 0.8 mm, the wear rate decreased by up to 15%, as fewer particles were transported, lowering the collision frequency. Conversely, smaller particles intensify component wear. Adjusting the blade wrap angle from 66° to 96° reduced impeller and volute wear by an estimated 20%, enhancing the durability but slightly decreasing the delivery capacity. Extending the blade's leading edge toward the intake improved the flow capacity, although it increased the wear frequency from one-third of the pressure surface to the trailing edge. [ABSTRACT FROM AUTHOR]

A submersible sewage pump is designed for conveying solid–liquid two-phase media containing sewage, waste, and fiber components, through its small and compact design and its excellent anti-winding and anti-clogging capabilities. In this paper, the computational fluid dynamics–discrete element method (CFD-DEM) coupling model is used to study the influence of different conveying conditions and particle parameters on the wear of the flow components in a submersible sewage pump. At the same time, the energy balance equation is used to explore the influence mechanism of different tip clearance sizes on the internal flow pattern, wear, and energy conversion mechanism of the pump. This study demonstrates that increasing the particle volume fraction decreases the inlet particle velocity and intensifies wear in critical areas. When enlarging the tip clearance thickness from 0.4 mm to 1.0 mm, the leakage vortex formation at the inlet is enhanced, leading to increased wear rates in terms of the blade and volute. Consequently, the total energy loss and turbulent kinetic energy generation increased by 3.57% and 2.25%, respectively, while the local loss coefficient in regard to the impeller channel cross-section increased significantly. The findings in this study offer essential knowledge for enhancing the performance and ensuring the stable operation of pumps under solid–liquid two-phase flow conditions. [ABSTRACT FROM AUTHOR]

Centrifugal slurry pumps and supporting combined piping systems (including U-shaped elbows and tees) are widely employed in deep-sea mining, the petrochemical industry, power metallurgy, and other industrial fields. The main aim of this research is to study the effects of conveying parameters and particle properties on the collision and erosion characteristics in a U-shaped elbow and the 100SHL4147 slurry pump. Investigation through the computational fluid dynamic–discrete element method is carried out on the collision mechanisms and erosion characteristics under different flow conditions. The collision and erosion characteristics are numerically investigated based on the analysis of frequency and erosion distribution. The results indicate that the erosion degree of non-spherical particles is more severe than that of spherical particles, while the collision frequency is the opposite in the U-shaped elbow. However, the collision and erosion of non-spherical particles are higher than those of spherical particles in the slurry pump. With the increase in the flow rate, the maximum collision frequency shows an upward trend, except for the shroud, and the maximum erosion rate of each wetted part increases. The area from the blade inlet to the one-third of the blade pressure surface is the main collision and erosion region, where the anti-wear performance should be strengthened. [ABSTRACT FROM AUTHOR]

In this paper, both unbalanced linguistic terms and a risk decision-making problem with developers' bounded rationality are considered; an integrated approach of Quality Function Deployment (QFD) and Cumulative Prospect Theory (CPT) is proposed to help increase customer satisfaction and facilitate product concepts selection. Firstly, QFD is employed to provide a customer-driven tool for developers, which can be used to generate product concept alternatives. Subsequently, enhanced information entropy is utilised to prioritise competing Customer requirements (CRs) based on unbalanced linguistic terms. These terms can be directly processed without being translated into fuzzy numbers, where the risk of information loss in fuzzification can be minimised. Product concept alternatives can be generated based on the outcomes of the subsequent QFD process. Moreover, CPT can be considered as a novel method by incorporating the developers' psychological characteristics under risk, which can help identify the most relevant product concepts. The cost prospect values of each alternative can be calculated by the function based on the cost reference point. The deficit and profit prospect values can be obtained by aggregating the values and weights of potential results, where functions from the enhanced CPT are used. The order of all alternatives can be ranked based on their overall prospect values. Finally, the proposed approach can be evaluated by a case study concerning the development of a new hydraulic breaker. The deliverables of this study are used to evaluate the relative advantages of the proposed approach over existing multi-attribute utility ones. [ABSTRACT FROM AUTHOR]

A 2-kW-class chemical oxygen-iodine laser (COIL) using nitrogen buffer gas is developed and tested since industrial applications of COIL devices would require the use of nitrogen as the buffer gas. The laser, with a gain length of 11.7cms, is energized by a square pipe-array jet-type singlet oxygen generator (SPJSOG) and employs a nozzle bank with a designed Mach number of 2.5.

Hydrogel‐based wearable electronic devices have received increasing attention. However, the construction of underwater strain sensors remains a significant challenge because of the swelling of hydrogels in an aquatic environment. This work presents the fabrication of an anti‐swellable hydrogel composed of polyvinyl alcohol (PVA), a copolymer of [2‐(methacryloyloxy) ethyl]dimethyl‐(3‐sulfopropyl) ammonium hydroxide (SBMA) and 2‐hydroxyethyl methacrylate. Interestingly, facile switch of the SBMA moiety from neutral to positively charged status at a low pH value leads to reduced osmotic pressure of the hydrogel for electrostatic repulsion‐driven elimination of water molecules and anti‐swelling. The resulting anti‐swellable hydrogel exhibits high toughness (518 kJ m−3) and compressive modulus (8.12 Mpa), ionic conductivity (up to 4.58 S m−1), and anti‐swelling behavior (equilibrium swelling ratio of 9% in water for 30 days). An underwater strain sensor based on this anti‐swellable hydrogel is further developed to monitor the movements of underwater sports. High sensitivity is achieved to identify multidirectional motions, including raising the head, swinging the arm, bending the elbow, knee and finger. Therefore, this study offers a facile strategy to generate hydrogel‐based sensors that can be adopted in an underwater environment as well as expands the potential applications of wearable electronic devices. [ABSTRACT FROM AUTHOR]