Tzuyang Yu

University of Massachusetts Lowell | UML · Department of Civil & Environmental Engineering

Distributed structure health monitoring has been a hot research topic in recent years, and optic fiber sensors are largely developed for the advantages of high sensitivity, better spatial resolution, and small sensor size. However, the limitation of fibers in installation and reliability has become one of the major drawbacks of this technology. Thi...

Presence of chloride ions is the main cause responsible for the corrosion of steel rebars and other components in concrete structures. Detecting the presence and amount of chloride ions in concrete, however, is a challenging task. In this paper, we present our development on the use of synthetic aperture radar (SAR) imaging for the remote detection...

Sinkholes form when culverts beneath roadways fail, posing a safety hazard that requires costly repairs and causes traffic delays. Detecting the onset of sub-pavement voids can prevent sudden pavement failure. This research presents an automated approach for increasing the detection accuracy of sub-pavement voids from infrared (IR) images collected...

This paper explored the Structural Health Monitoring (SHM) of pipelines by using fiber optic cables embedded into textiles and interrogated using Brillouin Optical Time Domain Reflectometry (BOTDR). Embedded fiber optic sensing textile would result in significant cost reduction by reducing installation time, which lowers the labor cost and the cost...

Roadways' sub-pavement voids caused by eroded soil through damaged culverts lead to safety hazards, traffic inconvenience, and expensive repairs. Infrared thermography (IRT) could help to identify those voids before the structural integrity of roadway pavements is compromised. However, IRT suffers from poor signal-to-noise ratio. This study impleme...

In structural health monitoring, distributed sensing offers a unique competitive advantage against discrete sensing in its improved spatial resolution and increased damage detectability. Improved spatial resolution is achieved by the developments in fiber-optical sensors. Increased damage detectability is enabled via spatial correlation among measu...

This chapter provides an overview on current laser-based sensing techniques and their applications in science and engineering. This chapter first introduces the principles of lasers, followed by a technical description of several laser-based sensing techniques including laser interferometry or electronic speckle pattern interferometry, digital shea...

Synthetic aperture radar (SAR) imaging is a remote sensing technique capable of performing noncontact subsurface inspection of dielectric materials like Portland cement concrete. Such techniques can be applied to field inspection of concrete structures and laboratory material characterization. The objective of this paper is to demonstrate the appli...

This user-friendly text shows how to use concise illustrations and college mathematics to understand and analyze fascinating dynamic phenomena in our everyday lives. Rather than providing a wide variety of disconnected topics in the field of dynamics, this book shows how these topics are fundamentally related and positioned in a framework. It also...

Distributed sensors have become a great advantage for Structural Health Monitoring (SHM) as they allow for the multiple points measurement using a single sensor. Nevertheless, the installation of this technology can be time-consuming and have an impact on the overall cost of the project. For this reason, this paper explores the application of diffe...

Synthetic aperture radar (SAR) imaging is a remote sensing technique capable of performing noncontact subsurface inspection of dielectric materials like Portland cement concrete. Such techniques can be applied to field inspection of concrete structures and laboratory material characterization.

Structural health monitoring (SHM) is crucial for extending service lives and preventing catastrophic failures of deteriorated infrastructures such as bridges, stadiums, and shopping centers from happening. An active all-optical photoacoustic ultrasound system (APUS) had been proposed. This paper investigates potential methods for measuring tempera...

In civil engineering, determining the subsurface moisture content and the water-to-cement (w∕c) ratio of concrete structures in the field is a challenging task. Moisture content of concrete structures regards the cement hydration level and short-term strength development of concrete, as well as the phase-distribution (solid, gaseous, and liquid) in...

In recent years, railway infrastructures and systems have played a significant role as a highly efficient transportation mode to meet the growing demand in transporting both cargo and passengers. Application of these structures in extreme environmental situation under severe working and loading conditions, caused by the traffic growth, heavier axle...

Utilization of [60]fullerosome monolayer grafting approach on both sides of graphene nano-sheets giving the corresponding sandwiched nanostructures was demonstrated as a key intermediate for the construction of photoswitchable and tunable dielectric graphene nanosheet materials. They were covered by magnetic plasmonic core-shell nanoparticles of γ[...

Subsurface moisture content in Portland cement concrete structures indicates the short-term (cement hydration) and long-term (durability) of these structures and can be used in the nondestructive evaluation (NDE) and structural health monitoring (SHM) of concrete structures. Subsurface moisture content of concrete structures provides insightful hea...

Condition assessment of masonry structures is important for maintaining their safety and durability. In this paper, a 10-GHz synthetic aperture radar (SAR) imaging system is proposed for assessing the condition of brick specimens. Three brick specimens of different sizes were manufactured and imaged remotely by the SAR system inside an anechoic cha...

Knowing the grain angle of structural wood members relative to the direction of loading is important in estimating their mechanical performance. The strength of a structural wood member can vary greatly depending on the orientation of grain, making the understanding of grain angle an essential requirement for machine grading and for structural anal...

The density of wood is one of the most important physical properties when it comes to understanding its mechanical behavior. The strength of a wood specimen is directly related to the amount of wood material in a given volume, making the accurate determination of density essential for the analysis of wood structures. The use of non-destructive eval...

An all-optical ultrasound sensing system based on photoacoustic principle is developed to monitor and investigate the initiation of early stage steel rebar corrosion in real time. The ultrasound generator was developed by small size gold nanocomposites coated optical fibers to generate 8-MHz bandwidth signals. The ultrasound receiver was applied by...

Detection of early-stage corrosion on slender steel members is crucial for preventing buckling failures of steel structures. An active photoacoustic fiber optic sensor (FOS) system is reported herein for the early-stage steel corrosion detection of steel plates and rebars using surface ultrasonic waves. The objective of this study is to investigate...

Novel 3D-configurated stereoisomers cis-cup-tris[C60>(DPAF-C9)] and trans-chairtris[ C60>(DPAF-C9)] were designed and synthesized in good yields. The former, with three C60>cages per molecule facing at the same side of the geometrical molecular cup-shape, was proposed to provide excellent binding interaction forces at the gold surface of core-shell...

Determining the subsurface moisture content of concrete structures in the field is an important but challenging task. This paper describes a new microwave nondestructive testing (NDT) technique using synthetic aperture radar (SAR) imaging at 10.5 GHz to estimate both the water-to-cement (w/c) ratio and moisture content of concrete panels. Three w/c...

Detection of early stage corrosion on slender steel members is crucial for preventing buckling failures of steel structures. An active photoacoustic fiber optic sensors (FOS) system has been reported for early stage steel corrosion detection of steel plates and rebars using surface ultrasonic waves. The objective of this paper is to investigate the...

Moisture content in concrete structures is commonly associated with many durability problems (e.g., steel corrosion, freeze-thaw) and can be used in structural health monitoring and nondestructive testing of concrete structures. In this paper, the use of synthetic aperture radar (SAR) imaging for characterizing subsurface moisture content and distr...

Determination of moisture content and distribution inside concrete structures using nonrestrictive test/evaluation is a challenging issue.

A new nanomaterial design was made by the construction of a tetralayered core-shell configuration, containing a magnetic core of nanospherical γ-FeOx particle (NP) encapsulated by one plasmonic gold subshell, one middle layer of electron-polarizable C60(>DPAF-Cn)x-derived fullerosome membrane, and an outer shell of organic electron-donors. This cla...

This article presents an application of an active all-optical photoacoustic sensing system with four elements for steel rebar corrosion monitoring. The sensor utilized a photoacoustic mechanism of gold nanocomposites to generate 8 MHz broadband ultrasound pulses in 0.4 mm compact space. A nanosecond 532 nm pulsed laser and 400 μm multimode fiber we...

Detection and quantification of moisture content inside wood (timber) is key to ensuring safety and reliability of timber structures. Moisture inside wood attracts insects and fosters the development of fungi to attack the timber, causing significant damages and reducing the load bearing capacity during their design life. The use of non-destructive e...

Surface and subsurface inspection of concrete structures provides useful information for the maintenance of these structures. Remote sensing techniques such as radar and microwave sensors enable engineers to assess structural condition with ease and efficiency. This paper reports the performance of a 10.5 GHz portable imaging radar system for the q...

Photogrammetric methods such as structure from motion (SFM) have the capability to acquire accurate information about geometric features, surface cracks, and mechanical properties of specimens and structures in civil engineering. Conventional approaches to verify the accuracy in photogrammetric models usually require the use of other optical techni...

Three C60-DPAF conjugates were synthesized with one as a linear monoadduct and two as branched or starburst multiadducts in structure for the investigation of chromophore antenna number-dependent tunability of RF-responses at 0.5–18 GHz. The effect was photoinduced by the generation of surface plasmonic resonance (SPR) at the surface of trilayered...

Modern improvised explosive device (IED) and mine detection sensors using microwave technology are based on ground penetrating radar operated by a ground vehicle. Vehicle size, road conditions, and obstacles along the troop marching direction limit operation of such sensors. This paper presents a new conceptual design using a rotary unmanned aerial...

As civil infrastructure (i.e. bridges, railways, and tunnels) continues to age; the frequency and need to perform inspection more quickly on a broader scale increases. Traditional inspection and monitoring techniques (e.g., visual inspection, mechanical sounding, rebound hammer, cover meter, electrical potential measurements, ultrasound, and ground...

Steel rebar corrosion reduces the integrity and service life of reinforced concrete (RC) structures and causes their gradual and sudden failures. Early stage detection of steel rebar corrosion can improve the efficiency of routine maintenance and prevent sudden failures from happening. In this paper, detecting the presence of surface rust in steel...

A feature extraction algorithm is proposed to quantitatively assess the condition of intact and damaged CFRP (carbon fiber reinforced polymer)-wrapped concrete cylinders using synthetic aperture radar (SAR) images. The proposed algorithm converts SAR images into a simplified representation, based on the shape, size, and amplitude of SAR images. In...

Deterioration of civil infrastructure in America demands routine inspection and maintenance to avoid catastrophic failures from occurring. Among many other non-destructive evaluations (NDE), photogrammetry is an accessible and realistic approach used for non-destructive evaluation (NDE) of a civil infrastructure systems. The objective of this paper...

Corrosion of steel reinforcing bars (rebars) is the primary cause for the deterioration of reinforced concrete structures. Traditional corrosion monitoring methods such as half-cell potential and linear polarization resistance can only detect the presence of corrosion but cannot quantify it. This study presents an experimental investigation of quan...

Fiber optic acoustic generators have generated a lot of interest due to its great potential in many applications including nondestructive tests. This paper reports four acoustic generation configurations. All the configurations are based on gold nanoparticles/polydimethylsiloxane (PDMS) composites. Since gold nanoparticles have high absorption effi...

The use of microwave and radar sensors in the nondestructive evaluation (NDE) of damaged materials and structures has been proven to be a promising approach. In this paper, a portable imaging radar sensor utilizing 10 GHz central frequency and stripmap synthetic aperture radar (SAR) imaging was applied to steel and wood specimens for size and range...