The high-speed and high-precision motorized spindle is the future development trend of the CNC machine tool field, and has become the focus of research in the world. High-speed motorized spindles tend to develop in the direction of high precision, high speed, low energy consumption, high efficiency, and high reliability. We undertake a through, systematic review of the development history perspective of the research on precision bearing technology, dynamic balancing technology, thermal error measurement and compensation technology with regard to the key technologies of high-speed motorized
The built environment is among the critical factors in older adults’ travel behavior, and a favorable built environment can encourage them to travel and engage in various activities. Existing studies have mostly focused on exploring the correlation between the built environment and travel behavior, ignoring the heterogeneity between the two at different times of the day. In this study, we conducted structured, face-to-face interviews in the Nanjing (China) metropolitan area to investigate the time consumed per trip by older adults using various travel modes and used the structural equatio
Suitable evaluation of distress is beneficial to understanding the in situ performance of deck pavement. This study attempts to evaluate the long-term in situ performance of American ChemCo epoxy asphalt concrete on the Xihoumen Bridge (XHMB) after 12 years of service. The traditional performance indexes were adopted to reveal the performance of XHMB. Then, based on the typical distresses, a new pavement performance index (PPI) was proposed to characterize the authentic distress condition. Finally, the performance evaluation and evolution were conducted. According to the results, the ruttin
Several types of fibers have enhanced the structural response of reinforced concrete-filled steel tubes (CFSTs). This article presents a state-of-the-art review of studies done on the axial compressive behavior of steel and glass fiber-reinforced CFSTs. The aim of using fibers is to improve the response of the CFSTs. This research indicates the findings of experimental programs and analytical evaluations of the effects of the fiber incorporation on the behavior of the CFSTs. The results of this research work demonstrate that steel fibers (SFs) have enough evident improving effects on the fa
A double-column self-centering pier fused with shear links is a novel structure developed to reduce residual deformation and facilitate post-earthquake repair. With this novel structure, the seismic resilience of bridges can be improved, and the reliability of lifeline infrastructure can be ensured. This paper presents the proposed pier configuration and investigates the mechanical behavior of the pier. A simplified finite element model is established to develop the lateral force-displacement relationship under cyclic loading. Additionally, a theoretical model based on the matrix displaceme
