Over the past decade, RNA sequencing (RNA-seq) has become an indispensable tool for transcriptome-wide analysis of differential gene expression and differential splicing of mRNAs. However, as next-generation sequencing technologies have developed, so too has RNA-seq. Now, RNA-seq methods are available for studying many different aspects of RNA biology, including single-cell gene expression, translation (the translatome) and RNA structure (the structurome). Exciting new applications are being explored, such as spatial transcriptomics (spatialomics). Together with new long-read and direct RNA-seq technologies and better computational tools for data analysis, innovations in RNA-seq are contributing to a fuller understanding of RNA biology, from questions such as when and where transcription occurs to the folding and intermolecular interactions that govern RNA function.

RNA sequencing: the teenage years

Time-reassigned synchrosqueezing transform: The algorithm and its applications in mechanical signal processing

Foreword Chapter 1 Introduction to SHM (Daniel L Balageas) Chapter 2 Vibration-based techniques for SHM (Claus-Peter Fritzen) Chapter 3 Fiber-optics sensors (Alfredo Guemes and Jose M Menendez) Chapter 4 SHM with piezoelectric sensors (Philippe Guy and Thomas Monnier) Chapter 5 SHM using electrical resistance (Michelle Salvia and Jean-Christophe Abry) Chapter 6 Low frequency electromagnetic techniques (Michel B Lemistre) Chapter 7 Capacitive methods for SHM in civil engineering (Xavier Derobert and Jean Iaquinta) Short Bibliographies of the Contributors Index

/pdf/structural-health-monitoring-37wv1pwxci.pdf

Structural health monitoring

Ultrasonic guided wave (UGW) is one of the most commonly used technologies for non-destructive evaluation (NDE) and structural health monitoring (SHM) of structural components. Because of its excellent long-range diagnostic capability, this method is effective in detecting cracks, material loss, and fatigue-based defects in isotropic and anisotropic structures. The shape and orientation of structural defects are critical parameters during the investigation of crack propagation, assessment of damage severity, and prediction of remaining useful life (RUL) of structures. These parameters become even more important in cases where the crack intensity is associated with the safety of men, environment, and material, such as ship’s hull, aero-structures, rail tracks and subsea pipelines. This paper reviews the research literature on UGWs and their application in defect diagnosis and health monitoring of metallic structures. It has been observed that no significant research work has been convened to identify the shape and orientation of defects in plate-like structures. We also propose an experimental research work assisted by numerical simulations to investigate the response of UGWs upon interaction with cracks in different shapes and orientations. A framework for an empirical model may be considered to determine these structural flaws.

Structural Health Monitoring (SHM) and Determination of Surface Defects in Large Metallic Structures using Ultrasonic Guided Waves.

This review introduces several areas of importance in acoustic emission (AE) technology, starting from signal attenuation. Signal loss is a critical issue in any large-scale AE monitoring, but few systematic studies have appeared. Information on damping and attenuation has been gathered from metal, polymer, and composite fields to provide a useful method for AE monitoring. This is followed by discussion on source location, bridge monitoring, sensing and signal processing, and pressure vessels and tanks, then special applications are briefly covered. Here, useful information and valuable sources are identified with short comments indicating their significance. It is hoped that readers note developments in areas outside of their own specialty for possible cross-fertilization.

/pdf/review-on-structural-health-evaluation-with-acoustic-2yceo4jr7o.pdf

Review on Structural Health Evaluation with Acoustic Emission

Dispersion of Lamb waves in a honeycomb composite sandwich panel.

Rayleigh to Lamb wave conversion at a delamination-like crack

Lamb wave propagation in a plate with step discontinuities

The research field of structural health monitoring (SHM) in the realm of civil engineering has emerged rapidly. SHM concepts are based on integrated sensors and actuators to evaluate the structural state. Beside common structural response methods and other nondestructive testing techniques, wave-based ultrasonic techniques are widely used especially because of their flexibility. Monitoring cable structures such as overhead transmission lines or stay cables in suspension bridges is one objective of those wave-based methods. These structures are subject to aging, corrosion and other static and dynamic loads (e.g., wind, temperature). The cylindrical structures act as waveguides whereby monitoring of large distances with a single ultrasonic transducer is possible. However, the wave propagation is multimodal and dispersive, which complicates analysis of the wave motion and development of monitoring applications. This work addresses several aspects of the propagation of guided waves in cylinders, especially the analysis of reflection and transmission at discontinuities using finite element and boundary element methods.

Structural health monitoring of cylindrical structures using guided ultrasonic waves

Structural Health Monitoring systems are developed to cost-efficiently prevent failure of mechanical and civil structures, and to predict the structure’s residual life. In this work, a damage detection algorithm based on the Hilbert transform of the recorded signals from induced guided ultrasonic waves is presented. By means of this algorithm, damage localization in multi-wire cables is performed through a time-of-flight analysis of the wave packets. The algorithm is fully automated and distinguishes between wave packets from different waves independently. Its applicability is analyzed for laboratory experiments on a single cylindrical wire and on multi-wire cables. As an additional damage indicator, second harmonic waves are evaluated. Furthermore, the possibility to perform damage identification by evaluating the waves’ amplitudes is analyzed. The amplitudes are compared with reference data from a novel hybrid finite-boundary element method.

https://hal.inria.fr/hal-01022061/document

Christoph Schaal

Papers

Dispersion of Lamb waves in a honeycomb composite sandwich panel.

Rayleigh to Lamb wave conversion at a delamination-like crack

Lamb wave propagation in a plate with step discontinuities

Structural health monitoring of cylindrical structures using guided ultrasonic waves

Damage detection in multi-wire cables using guided ultrasonic waves