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Search Publications by: Jack F. Douglas (Assoc)

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Displaying 1 - 25 of 713

Dielectric Characterization of H2O and CO2 Uptake by Polyethylenimine Films

April 10, 2024
Author(s)
Jan Obrzut, Jennifer Clark, Avery Baumann, Jack F. Douglas
This study investigates the dielectric properties of branched polyethylenimine (PEI) films in relation to their interaction with moisture and CO2. The dielectric measurements were carried out using a non-contact resonant microwave cavity testing method

A quantitative theoretical model of the boson peak based on stringlet excitations

July 24, 2023
Author(s)
Jack F. Douglas, Cunyuan Jiang, Matteo Baggioli
The boson peak (BP), a low-energy excess in the vibrational density of states over the phonon Debye contribution, is usually identified as one of the distinguishing features between ordered crystals and amorphous solid materials. Despite decades of efforts

Prestress in Composite Polymer Gels as a Model for Articular Cartilage

November 2, 2022
Author(s)
Alexandros Chremos, Jack F. Douglas, Peter Basser, Ferenc Horkay
Articular cartilage is a composite gel-like material found in animal and human joints and exhibits a unique load-bearing performance that has been challenging to reproduce in synthetic materials and in molecular dynamics simulations. We investigate a

Effects of Aspect Ratio of Multi-Walled Carbon Nanotube on Flammability Properties of Polymer Nanocomposites

October 12, 2021
Author(s)
Bani Cipiriano, Takashi Kashiwagi, Srinivasa R. Raghavan, Ying Yang, E A. Grulke, Kazuya Yamammoto, John R. Shields, Jack F. Douglas
The effects of the aspect ratio of multi-walled carbon nanotube (MWNT) on viscoelastic properties and flammability properties of PS/MWNT nanocomposites are studied with two different MWNTs having average aspect ratios of 49 and 150. While no significant

Fluctuation Effects on Surface Pattern Formation in Thin Block Copolymer Films

October 12, 2021
Author(s)
A C. Smith, Jack F. Douglas, Eric J. Amis, Alamgir Karim
Hole formation on the surface of thin block copolymer films is investigated as a function of time (t), temperature (T) and film thickness. The size of the holes, h s, approaches a steady state value at long times h s,∞ = h s(t -> ∞) and we introduce a

Laser Based Angle-Resolved Photoemission, the Sudden Approximation and Quasiparticle-Like Spectral Peaks in Bi 2 Sr 2 Cu 2 O 8 +D

October 12, 2021
Author(s)
j D. Koralek, Jack F. Douglas, N C. Plumb, Z Sun, A V. Fedorov, M M. Murnane, H C. Kapteyn, Steven T. Cundiff, Y Aiura, K Oka, H. Eisaki, D S. Dessau
A new low photon energy regime of angle-resolved photoemission spectroscopy is accessed with lasers and used to study the hight T c superconductor Bid2^CaCu 2O 8d+^delta. The low energy increases bulk sensitivity, reduces background, and improves

Model for Dispersion Rheology

October 12, 2021
Author(s)
J Bicerano, Jack F. Douglas, D A. Brune
A general model of the viscosity of complex-shaped particle dispersions is developed based on an exact virial expansion about the low concentration limit and a mathematical analogy between the hydrodynamics of concentrated particle suspensions and the