Over the past decade, Unmanned Aerial Vehicles (UAVs) have emerged as essential tools for landslide studies, particularly in on-site investigations. This paper reviews UAV applications in landslide studies, with a focus on static geological characteristics, monitoring temporal and spatial dynamics, and responses post-events. We discuss the functions and limitations of various types of UAVs and sensors (RGB cameras, multi-spectral cameras, thermal IR cameras, SAR, LiDAR), outlining their roles and data processing methods in landslide applications. This review focuses on the UAVs’ roles in landslide geology surveys, emphasizing landslide mapping, modeling and characterization. For change monitoring, it provides an overview of the temporal and spatial evolution through UAV-based monitoring, shedding light on dynamic landslide processes. Moreover, this paper underscores UAVs’ crucial role in emergent response scenarios, detailing strategies and automated detection using machine learning algorithms. The discussion on challenges and opportunities highlights the need for ongoing UAV technology advancements, addressing regulatory hurdles, hover time limitations, 3D reconstruction accuracy and potential integration with technologies like UAV swarms.
Micro-hole aerostatic bearings have emerged as critical components in ultra-precision machining systems, offering a superior load capacity, stiffness, and stability compared to traditional orifice-based designs. These enhancements are primarily attributed to the high-density configurations of micro-holes and the reduction in hole diameter. However, research on the design and analysis of micro-hole aerostatic bearings for high-rotational-speed applications remains limited. In this study, the finite element method (FEM) was employed to solve the Reynolds equation, thereby conducting a systematic evaluation of the static and high-speed performance characteristics of micro-hole aerostatic thrust bearings. The effects of restrictor types, micro-hole layouts, structural parameters, and centrifugal deformation under high-rotational-speed conditions on bearing performance have been comprehensively examined. The objective of this study is to provide a basis for the design of micro-hole high-speed aerostatic spindles.
Advancements in manufacturing technology have facilitated the use of micro-orifice restrictors (MORs) in aerostatic bearings. However, the understanding of their effectiveness in journal bearings remains limited. This study utilizes FEM for solving the nonlinear Reynolds equation, incorporating velocity terms, to analyze the characteristics of aerostatic journal bearings (AJBs). The concepts of air impedance and pressure range are introduced and applied to explain the advantages of MORs over traditional orifice restrictors (TORs). Furthermore, the centrifugal deformation of the air film induced by high-speed operations and its consequential impact on bearing performance are methodically examined in detail. Finally, an experimental study is executed to confirm the proposed model and support the pertinent design principles. The experiment indicates that the air film thickness, accounting for centrifugal deformation, aligns more closely with the high-speed operating conditions characteristic of AJBs.