A5011437112- Ultrasonics and Acoustic Wave Propagation
- Thermography and Photoacoustic Techniques
- Advanced Fiber Optic Sensors
- Photoacoustic and Ultrasonic Imaging
- Force Microscopy Techniques and Applications
- Photonic and Optical Devices
- Acoustic Wave Resonator Technologies
- Mechanical and Optical Resonators
- Thermal properties of materials
- Optical Coherence Tomography Applications
- Thermal Radiation and Cooling Technologies
- Seismic Waves and Analysis
- Near-Field Optical Microscopy
- Structural Health Monitoring Techniques
- Advanced Fiber Laser Technologies
- Plasmonic and Surface Plasmon Research
- Bacterial biofilms and quorum sensing
- Cellular Mechanics and Interactions
- Advanced MEMS and NEMS Technologies
- 2D Materials and Applications
- Geophysics and Sensor Technology
- Design Education and Practice
- Graphene research and applications
- Manufacturing Process and Optimization
- Geophysical Methods and Applications
Northwestern University
2005-2024
Northwestern University
2015-2024
Jomo Kenyatta University of Agriculture and Technology
2024
University of Lagos
2019
McCormick (United States)
2013
Hong Kong Polytechnic University
2011
Johns Hopkins University
2009
Lawrence Livermore National Laboratory
2009
International Institute for Nanotechnology
2008
Nuance Communications (Austria)
2008
Abstract Grain‐boundary engineering is an effective strategy to tune the thermal conductivity of materials, leading improved performance in thermoelectric, thermal‐barrier coatings, and management applications. Despite central importance transport, a clear understanding how grain boundaries modulate microscale heat flow missing, owing scarcity local investigations. Here, imaging individual demonstrated thermoelectric SnTe via spatially resolved frequency‐domain thermoreflectance....
A novel laser-based ultrasonic technique for the inspection of thin plates and membranes is presented, in which a modulated continuous-wave laser source used to excite narrow bandwidth Lamb waves. The dominant feature acoustic spectrum sharp resonance peak that occurs at minimum frequency first-order symmetric mode, where group velocity wave goes zero while phase remains finite. Experimental results with receiver on epicenter demonstrate zero-group generated low-power excitation can be...
Recent reports on the thermoelastic generation of Lamb waves in isotropic elastic plates show that a laser source efficiently excites resonance occurs at minimum frequency first order symmetric (S1) mode. The group velocity wave goes to zero this while phase remains finite, and is referred as S1 (S1 ZGV) resonance. ZGV can be employed for nondestructive evaluation properties or plate thickness. A model using an intensity-modulated continuous developed used study behavior effects parameters...
A passive structural health monitoring (SHM) system for locating foreign-object impact using a network of fiber Bragg grating (FBG) sensors that monitor high frequency dynamic strains is described. The FBG sensor signals are adaptively demodulated two-wave mixing (TWM) spectral demodulator. Strains applied on the encoded as wavelength shifts light reflected by which then converted into phase and TWM interferometer. demodulator compensates low drifts caused large quasi-static strain...
Two-dimensional transitional metal halides have recently attracted significant attention due to their thickness-dependent and electrostatically tunable magnetic properties. However, this class of materials is highly reactive chemically, which leads irreversible degradation catastrophic dissolution within seconds in ambient conditions, severely limiting subsequent characterization, processing, applications. Here, we impart long-term stability the prototypical transition halide CrI3 by...
Abstract Hydrogel-encapsulated catalysts are an attractive tool for low-cost intensification of (bio)-processes. Polyvinyl alcohol-sodium alginate hydrogels crosslinked with boric acid and post-cured sulfate (PVA-SA-BS) have been applied in bioproduction water treatment processes, but the low pH required crosslinking may negatively affect biocatalyst functionality. Here, we investigate how (3, 4, 5) time (1, 2, 8 h) physicochemical, elastic, process properties PVA-SA-BS beads. Overall, bead...
Abstract Engineering microstructural defects, like grain boundaries, offers superior control over transport properties in energy materials. However, technological advancement requires establishing microstructure‐property relations at the micron or finer scales, where most of these defects operate. Here, first experimental evidence thermal resistance for individual silicon estimated with a Gibbs excess approach, is provided. Coincident site lattice boundaries exhibit uniform along same...
In this paper, an innovative method to create embedded microchannels is presented. The presented technology based on a direct-write technique using scanning laser system pattern single layered SU-8. enormous flexibility of the can be seen in two key features: pulsing controlled spot-by-spot with variable exposure doses, and intensity penetrating into samples adjusted by varying focus level. UV greatly simplifies fabrication processes. Moreover, it set up conventional manufacturing...
Non-propagating evanescent fields play an important role in the development of nano-photonic devices. While detecting far-field can be accomplished by coupling it to propagating waves, practice they are measured presence unwanted background components. It leads a poor signal-to-noise ratio and thus errors quantitative analysis local fields. Here we report on plasmonic near-field scanning optical microscopy (p-NSOM) technique that incorporates nanofocusing probe for adiabatic focusing surface...
A laser-based acoustic microscopy system has been developed that uses an amplified electroabsorption modulated diode laser for narrow bandwidth wave generation at frequencies up to 200 MHz. The detection reduction afforded by this technique allows a significant improvement in signal-to-noise ratio over systems using pulsed-laser excitation and broadband detection. Femtometer range displacement sensitivity is demonstrated, allowing materials characterization with only minimal surface heating....
Elastic guided waves were generated in mixed-culture bacterial biofilms for characterizing its viscoelastic properties.
Abstract Deep generative models have demonstrated effectiveness in learning compact and expressive design representations that significantly improve geometric optimization. However, these do not consider the uncertainty introduced by manufacturing or fabrication. The past work quantifies such often makes simplifying assumptions on variations, while “real-world,” “free-form” its impact performance are difficult to quantify due high dimensionality. To address this issue, we propose a...
Ultrasonic waves are sensitive to the elastic properties of solids and have been applied in a variety nondestructive materials characterization metrology applications. The spatial resolution established ultrasound techniques is limited order wavelength, which insufficient for nanomechanical imaging nanoscale aspects material microstructure. Here, we report an ultrasonic near-field optical microscopy (UNOM) technique that enables local mapping with deep sub-optical wavelength resolution. In...
Abstract Morphological parameters are commonly used to predict transport and metabolic kinetics in biofilms. Yet, quantification of biofilm morphology remains challenging because imaging technology limitations lack robust analytical approaches. We present a novel set image analysis techniques estimate internal porosity, pore size distributions, network connectivity depth 1 mm at resolution 10 µm exhibiting both heterotrophic nitrifying activities. Optical coherence tomography (OCT) scans...