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Full-Text Articles in Engineering

Evaluation Of Low And High Frequency Dynamic Response For Condition Assessment Of Reinforced Concrete Structures, Ali Hafiz Aug 2019

Evaluation Of Low And High Frequency Dynamic Response For Condition Assessment Of Reinforced Concrete Structures, Ali Hafiz

Dissertations and Theses

Concrete is widely used for civil infrastructure structures and they experience deterioration and degradation due to aging, increases in the traffic loads, harsher environmental conditions, use of deicing chemicals, etc. Therefore, evaluating the integrity of reinforced concrete structures has become of increasing interest for infrastructure owners and managers. A number of non-destructive testing (NDT) and structural health monitoring (SHM) methods have been developed in recent decades to aid in evaluating structures and provide input for asset management. One family of these methods uses the dynamic response of a structural member: stress waves (high frequency) and structural vibrations (low frequency). Both ...


Physics-Based Signal Processing Methods For Terahertz Non-Destructive Evaluation Of Layered Media, Scott G. Schecklman Jun 2019

Physics-Based Signal Processing Methods For Terahertz Non-Destructive Evaluation Of Layered Media, Scott G. Schecklman

Dissertations and Theses

In recent years Terahertz (THz) time domain spectroscopy has emerged as a promising new technology with potential applications in a variety of fields, including industrial manufacturing, security screening and medical imaging. Pulsed THz systems are uniquely suited for non-destructive evaluation (NDE) of the sub-surface layers of dielectric packaging and coating materials, because they provide high dynamic range over a wide bandwidth in the far infrared portion of the electromagnetic spectrum. Often the dielectric materials of the packaging and/or surface coating layers exhibit relatively low loss and abrupt changes in the refractive index at the layer boundaries can be observed ...


Passively-Coded Embedded Microwave Sensors For Materials Characterization And Structural Health Monitoring (Shm), Katelyn Rose Brinker Jan 2019

Passively-Coded Embedded Microwave Sensors For Materials Characterization And Structural Health Monitoring (Shm), Katelyn Rose Brinker

Masters Theses

"Monitoring and maintaining civil, space, and aerospace infrastructure is an ongoing critical problem facing our nation. As new complex materials and structures, such as multilayer composites and inflatable habitats, become ubiquitous, performing inspection of their structural integrity becomes even more challenging. Thus, novel nondestructive testing (NDT) methods are needed. Chipless RFID is a relatively new technology that has the potential to address these needs. Chipless RFID tags have the advantage of being wireless and passive, meaning that they do not require a power source or an electronic chip. They can also be used in a variety of sensing applications including ...


Hardware Architectures For Compact Microwave And Millimeter Wave Cameras, Matthew Jared Horst Jan 2019

Hardware Architectures For Compact Microwave And Millimeter Wave Cameras, Matthew Jared Horst

Doctoral Dissertations

"Millimeter wave SAR imaging has shown promise as an inspection tool for human skin for characterizing burns and skin cancers. However, the current state-of-the-art in microwave camera technology is not yet suited for developing a millimeter wave camera for human skin inspection. Consequently, the objective of this dissertation has been to build the necessary foundation of research to achieve such a millimeter wave camera. First, frequency uncertainty in signals generated by a practical microwave source, which is prone to drift in output frequency, was studied to determine its effect on SAR-generated images. A direct relationship was found between the level ...