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During the construction of concrete ship locks, prolonged interruptions between the casting of the floor and lock wall are inevitable. In terms of mass concrete, long placement delays are one of the major reasons for the presence of cracks in newly placed concrete. Therefore, this study examines both the placement and structural characteristics of ship locks after long casting interruptions based on the mass concrete thermal stress theory to determine the major causal factors for cracks in newly poured concrete. Specifically, a block placement method is proposed to reduce thermal stress in newly placed concrete, and the temperature control and crack prevention capacities of the proposed method are verified using the finite element method. The development of the structure's thermal stress under different temperature control measures is analyzed, finding that thermal stress in the lock walls can be effectively reduced by 50% through low-temperature block casting. The results demonstrate that the proposed method can significantly reduce the internal thermal stress of newly placed concrete after prolonged casting interruptions, thereby highlighting its applicability for achieving effective temperature control and crack prevention in concrete ship locks. [ABSTRACT FROM AUTHOR]

A bearingless switched motor with permanent magnets in the stator yoke (BSRM-PMSY) with two sets of windings on each stator tooth pole is studied. The current in one set of windings mainly controls the motor torque, and rotor suspension can be realised by adjusting the current in the other set of windings. Each stator module unit of the motor is composed of a permanent magnet and two U-shaped iron cores. Finally, a BSRM-PMSY finite element simulation model is established to explore the static characteristics of the motor, including magnetic field distribution, permanent magnet flux linkage and harmonic analysis, back electromotive force (EMF) and harmonic analysis, suspension performance, and so on. The analysis of the simulated results lays a foundation for the establishment of a BSRM-PMSY mathematical model and control system. [ABSTRACT FROM AUTHOR]

Simple Summary: Due to technical limitations, few studies on the supine position have focused on spinal curvature measurement. This study used a novel technique to measure spinal curvature in the supine position and obtain intervertebral disc pressures through computational simulation. The results revealed an increased craniocervical height when lying on a soft mattress, leading to significantly increased cervical disc loading. The lumbar lordosis was reduced when using the hard mattress, and contact pressure significantly increased. Thus, a medium mattress appeared to be more suitable to use. In cases where a soft mattress is used, the use of a softer or thinner pillow should be considered. Sleeping support systems can influence spinal curvature, and the misalignment of the spinal curvature can lead to musculoskeletal problems. Previous sleep studies on craniocervical support focused on pillow variants, but the mattress supporting the pillow has rarely been considered. This study used a cervical pillow and three mattresses of different stiffnesses, namely soft, medium, and hard, with an indentation load deflection of 20, 42, and 120 lbs, respectively. A novel electronic curvature measurement device was adopted to measure the spinal curvature, whereby the intervertebral disc loading was computed using the finite element method. Compared with the medium mattress, the head distance increased by 30.5 ± 15.9 mm, the cervical lordosis distance increased by 26.7 ± 14.9 mm, and intervertebral disc peak loading increased by 49% in the soft mattress environment. Considering that the pillow support may increase when using a soft mattress, a softer or thinner pillow is recommended. The head distance and cervical lordosis distance in the hard mattress environment were close to the medium mattress, but the lumbar lordosis distance reduced by 10.6 ± 6.8 mm. However, no significant increase in intervertebral disc loading was observed, but contact pressure increased significantly, which could cause discomfort and health problems. [ABSTRACT FROM AUTHOR]

In this paper, 3D particulate scale modelling on the die compaction of DEM generated initial packings of both soft and hard particles was conducted by employing the multiparticle finite element method (MPFEM). The effects of initial packing structures as well as the compaction pressure on the macroscopic and microscopic properties of the whole powder mass and local structures were investigated. In addition, corresponding physical experiments were carried out for model validation. The results show that the compact obtained from the initial dense packing under vibration undergoes yielding stage earlier than that with natural initial packing (without vibration), and the relative density is much higher. Pores that are significantly smaller and with more uniform size and homogenous stress distribution are observed in the former case. Highest stress regions occur in most cases at a grain boundary with large curvature after deformation. Moreover, the high stress in the central part of both soft and hard particles during compaction is significantly reduced after pressure unloading, reaching a new force balance. In this case, the stress is concentrated mainly at the corners of the deformed particles, which creates the risk of cracking during subsequent sintering at either the contact region between particles or the corners. The numerical results are found to be in good agreement with those from physical experiments, confirming the robustness and reliability of the numerical model used in the simulations. [ABSTRACT FROM AUTHOR]