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Advanced Signal Processing, System Identification, and Machine Learning for Structural Health Monitoring

Structural Health Monitoring (SHM) is an interdisciplinary engineering field that combines structural mechanics, vibration analysis, signal processing, system identification, statistical analysis, and artificial intelligence to evaluate the condition and performance of civil infrastructure. Bridges, high-rise buildings, dams, tunnels, and other critical structures are continuously exposed to environmental and operational influences, including wind, traffic, temperature variations, earthquakes, and material deterioration. These influences generate dynamic responses that can be measured using accelerometers, strain gauges, displacement sensors, inclinometers, and other sensing technologies. The primary objective of SHM is not simply to detect unusual sensor measurements. Rather, it is to determine whether changes in measured responses indicate variations in environmental conditions, sensor malfunctions, changes in structural properties, or potentially significant struc...
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Dimensionless Numbers in Transport Phenomena: Heat Transfer, Fluid Mechanics, and Mass Transfer

Dimensionless numbers are fundamental tools in chemical engineering, mechanical engineering, and transport phenomena. They are used to describe the relative importance of different physical mechanisms, including fluid inertia, viscous forces, heat conduction, convection, molecular diffusion, and buoyancy. Instead of analyzing every physical property and operating parameter independently, engineers can combine them into dimensionless groups that reveal the dominant physical processes in a system. Eleven important dimensionless numbers are the Biot number (Bi), Fourier number (Fo), Grashof number (Gr), Nusselt number (Nu), Prandtl number (Pr), Rayleigh number (Ra), Reynolds number (Re), Schmidt number (Sc), Sherwood number (Sh), Stanton number (St), and Lewis number (Le). These numbers are closely related. Some describe fluid flow, some characterize heat or mass transfer, and others compare multiple transport mechanisms. Understanding their physical meanings and mathem...
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A Practical View of Work in Closed and Open Thermodynamic Systems

Thermodynamics contains a large number of equations, but an engineer does not always need to memorize all of them independently. For many practical problems, especially in chemical and mechanical engineering, it is more useful to identify what kind of system we are dealing with and how energy is transferred. A simple way to organize the subject is to separate thermodynamic systems into closed systems and open systems . An even more useful way to think about the first law is to treat it like an energy accounting system. The system is like an account: energy can enter, leave, or remain stored inside the system. The first law simply keeps the account balanced. 1. The First Law as Energy Accounting The first law of thermodynamics is fundamentally an accounting equation. Using the common engineering convention in which heat entering the system and work done on the system are positive: \[ \boxed{\Delta U=Q+W} \] The interpretation is straightforward: \(Q...
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