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Displaying 1 - 25 of 50

Scaling the Projectile Perforation Resistance of Soft Materials

June 29, 2023
Author(s)
Katherine Evans, Shawn Chen, Amanda Souna, Stephan J. Stranick, Christopher Soles, Edwin P. Chan
From space dust to ballistic impact, controlling or mitigating a high velocity projectile impact event is a desirable outcome. The design and development of new and novel impact mitigating materials are greatly hindered by the use of macroscale projectile

Reaction-Induced Phase Separation (RIPS) in Amine-Cured Epoxy/Epoxy Thermosets.2. Visualization of Heterogeneity using Fluorescence Lifetime Imaging Microscopy (FLIM)

February 25, 2023
Author(s)
Jeremiah Woodcock, Stephan J. Stranick, Anthony Kotula, Gale A. Holmes
The strategic integration of a rhodamine-spirolactam (RS) mechanophore into a transparent bis-epoxide/bis-epoxide/amine and corresponding bis-epoxide/amine networks has revealed, for the first time using fluorescence lifetime imaging microscopy (FLIM)

A Non-Intrusive Fluorescent Pattern for Internal Microscale Strain Measurements Using Digital Image Correlation

February 1, 2023
Author(s)
Ami Ahure Powell, William Mulhearn, Shawn Chen, Stephan J. Stranick, Jeffrey Gilman, Mark Iadicola, Jeremiah Woodcock
A non-intrusive and non-disruptive internal fluorescent pattern is designed, developed, and tested using digital image correlation (DIC), an effective non-contact optical method, to measure deformation at internal planes of a polymer matrix material. The

Activation of Mechanophores in a Thermoset Matrix by Instrumented Scratch

November 17, 2021
Author(s)
Chelsea S. Davis, Jeremiah Woodcock, Ryan Beams, Mitchell Rencheck, Muzhou Wang, Stephan J. Stranick, Aaron M. Forster, Jeffrey Gilman
Scratches in polymer coatings and barrier layers negatively impact optical properties (haze, light transmission, etc.), initiate routes of degradation or corrosion (moisture permeability), and nucleate delamination of the coating. Detecting scratches in

Enhanced Near-Field Raman Spectroscopy

October 12, 2021
Author(s)
C E. Dentinger, Stephan J. Stranick, Lee J. Richter, Richard R. Cavanagh
Near-field Raman spectroscopy can be used to obtain chemical specificity with the subwavelength spatial resolution of near-field scanning optical microscopy (NSOM). We report detailed measurements of near-field Raman spectra from a single crystal diamond

Towards Absolute Viability Measurements for Bacteria

September 12, 2021
Author(s)
Joy Dunkers, Hariharan K. Iyer, Brynna H. Jones, Charles Camp, Stephan J. Stranick, Nancy Lin
Quantifying viable, vegetative bacteria is a critical measurand in healthcare diagnostics, food safety, and antimicrobial development. Viability determination has traditionally relied on such techniques as plate counting, colorimetric or fluorescent

Fluorescence Microscopy Reveals Structure-Property Relationships and Polymer Dynamics in Biocomposites

July 21, 2021
Author(s)
Quinn Easter, Shawn Chen, Jeremiah Woodcock, Amanda Souna, Sindhu Seethamraju, Jan Obrzut, Douglas M. Fox, Stephan J. Stranick, Jeffrey Gilman
OBJECTIVES: Developing the next generation of materials for use in restorative work requires a multifaceted approach. While mimicking the properties of the tooth, currently available dental composites and porcelains eventually fail and require replacement

Flourescently labeled cellulose nanofibers for environmental health and safety studies

April 9, 2021
Author(s)
Jeremiah Woodcock, Ilabahen A. Patel, Ryan Beams, Stephan J. Stranick, Jeffrey W. Gilman, Douglas M. Fox, Marina Mulenos, Christie Sayes, Maryam Salari, Deloid Glen, Philip Demokritou, Bryan Harper, Harper Stacey, Ong Kimberly, Jo Anne Shatkin
An optimal methodology for locating and tracking cellulose nanofibers (CNF) in vitro and in vivo is crucial to evaluate the environmental health and safety properties of these nanomaterials. Here, we report the use of a new boron-dipyrromethene (BODIPY)

Damage sensing using a mechanophore crosslinked epoxy resin in single-fiber composites

May 26, 2020
Author(s)
Jeremiah W. Woodcock, Richard J. Sheridan, Ryan Beams, Stephan J. Stranick, William F. Mitchell, Jeffrey W. Gilman, Gale A. Holmes, Catherine L. Brinson, Vamshi Gudapati, hartman David, Amol Vaidya
Natural and man-made composite materials must be tough, durable and damage tolerant1,2. For man-made composites to rival, or exceed, the dynamic, multifunctional performance of natural materials new information about the fundamental mechanisms responsible

Using Microprojectiles to Study the Ballistic Limit of Polymer Thin Films

April 1, 2020
Author(s)
Shawn H. Chen, Amanda J. Souna, Christopher L. Soles, Stephan J. Stranick, Edwin P. Chan
The dynamic impact between a particle and a planar material is important in many high impact events, andthereisagrowingneedtocharacterizethemechanicalpropertiesoflight-weightpolymeric materials at dynamic loading conditions. Here, a laser-induced

The structural phases and vibrational properties of Mo1-xWxTe2 alloys

September 1, 2017
Author(s)
Sean M. Oliver, Ryan Beams, Sergiy Krylyuk, Arunima Singh, Irina Kalish, Alina Bruma, Francesca Tavazza, Iris Stone, Stephan J. Stranick, Albert Davydov, Patrick M. Vora
The structural polymorphism in transition metal dichalcogenides (TMDs) provides exciting opportunities for developing advanced electronics. For example, MoTe2 crystallizes in the 2H semiconducting phase at ambient temperature and pressure, but transitions

Rapid Wafer-Scale Growth of Polycrystalline 2H-MoS2 by Pulsed Metalorganic Chemical Vapor Deposition

July 12, 2017
Author(s)
Berc Kalanyan, William A. Kimes, Ryan Beams, Stephan J. Stranick, Elias J. Garratt, Irina Kalish, Albert Davydov, Ravindra Kanjolia, James E. Maslar
High volume manufacturing of devices based on transition metal dichalcogenide (TMD) ultra-thin films will require deposition techniques that are capable of reproducible wafer-scale growth with monolayer control. To date, TMD growth efforts have largely

Phase mask-based multimodal superresolution microscopy

July 6, 2017
Author(s)
Ryan Beams, Jeremiah W. Woodcock, Jeffrey W. Gilman, Stephan J. Stranick
We demonstrate a multimodal superresolution microscopy technique based on a phase masked excitation beam in combination with spatially filtered detection. The theoretical foundation for calculating the focus from a non-paraxial beam with an arbitrary

Identification of the Crystal Symmetry in 1T' MoTe2 with Polarization-Resolved Second Harmonic Generation and Raman Scattering

October 13, 2016
Author(s)
Ryan Beams, Luiz Gustavo Cancado, Sergiy Krylyuk, Irina Kalish, Berc Kalanyan, Arunima Singh, Kamal Choudhary, Patrick Vora, Francesca M. Tavazza, Albert Davydov, Stephan J. Stranick
We study the crystal symmetry properties of few-layer 1T' MoTe2 using the polarization dependence of the second harmonic generation (SHG) and Raman scattering. Bulk 1T' MoTe2 is know to be inversion symmetric, however, we nd that the inversion symmetry is

Assessing Electron Backscattered Diffraction and Confocal Raman Microscopy Strain Mapping Using Wedge-indented Si

February 17, 2016
Author(s)
Lawrence Henry Friedman, Mark D. Vaudin, Stephan J. Stranick, Gheorghe Stan, Yvonne B. Gerbig, William Alexander Osborn, Robert F. Cook
The accuracy of electron backscattered diffraction (EBSD) and confocal Raman microscopy (CRM) for small-scale strain mapping are assessed using the multi-axial strain field surrounding a wedge indentation in Si as a test vehicle. The strain field is

Noncontact conductivity and dielectric measurement for high throughput roll-to-roll nanomanufacturing

November 23, 2015
Author(s)
Nathan D. Orloff, Christian J. Long, Jan Obrzut, Laurent Millaud, Francesca Mirri, Thomas R. Kole, Robert D. McMichael, Mattei Pasquali, Stephan J. Stranick, James A. Liddle
Advances in roll-to-roll processing of graphene [1] and carbon nanotube [2] have at last led to the continuous production of high-quality coatings and filaments, ushering in a wave of applications for flexible [3], [4] and wearable [5] electronics, woven

Stress mapping of micromachined polycrystalline silicon devices via confocal Raman microscopy

June 15, 2014
Author(s)
Grant A. Myers, Siddharth Hazra, Maarten de Boer, Chris A. Michaels, Stephan J. Stranick, Ryan P. Koseski, Robert F. Cook, Frank W. DelRio
Stress mapping of micromachined polycrystalline silicon devices with components in various levels of uniaxial tension was performed. Confocal Raman microscopy was used to form two-dimensional maps of Raman spectral shifts, which exhibited variations on the

Comparison of the Properties of Cellulose Nanocrystals and Cellulose Nanofibrils Isolated From Bacteria, Tunicate, and Wood Processed Using Acid, Enzymatic, Mechanical, and Oxidative Methods

April 18, 2014
Author(s)
Iulia A. Sacui, Jeffrey W. Gilman, Ryan C. Nieuwendaal, Stephan J. Stranick, Henryk Szmacinski, Mehdi Jorfi, Christopher Weder, Johan Foster, Richard Olsson, Daniel Burnett
This work describes the study and characterization of native cellulose nanocrystals and nanofibrils (CNCs, CNFs), whose crystallinity, morphology, aspect ratio, and surface chemistry depend on the raw material source and hydrolysis conditions. Measurement

Micro-scale measurement and modeling of stress in silicon surrounding a tungsten-filled through-silicon via

October 11, 2011
Author(s)
Ryan P. Koseski, William Alexander Osborn, Stephan J. Stranick, Frank W. DelRio, Mark D. Vaudin, Thuy Dao, Vance H. Adams, Robert F. Cook
The stress in silicon surrounding a tungsten-filled through-silicon via (TSV) is measured using confocal Raman microscopy line scans across the TSV both before and after etch removal of an oxide stack used as a mask to define the TSV during fabrication

Comparison of the Sensitivity and Image Contrast in Spontaneous Raman and Coherent Stokes Raman Scattering Microscopy of Geometry Controlled Samples

February 9, 2011
Author(s)
Hyun M. Kim, Chris A. Michaels, Garnett W. Bryant, Stephan J. Stranick
We experimentally compare the performance and contrast differences between spontaneous and coherent Stokes Raman scattering microscopy. We demonstrate the differences on a series of geometry controlled samples that range in complexity from a point (array

Measurement of residual stress field anisotropy at indentations in silicon

June 23, 2010
Author(s)
Yvonne B. Gerbig, Stephan J. Stranick, Robert F. Cook
The residual stress field around spherical indentations on single crystal silicon (Si) of different crystallographic orientation is mapped by confocal Raman microscopy. All orientations exhibit an anisotropic stress pattern with an orientation specific