U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Search Publications by: Andrew J Allen (Fed)

Search Title, Abstract, Conference, Citation, Keyword or Author
Displaying 26 - 50 of 257

Synthesis, Structural and Sorption Characterization of a Hofmann Compound, Ni(3-Methy-4,4'-bipyridine)[Ni(CN)4]

March 6, 2021
Author(s)
Winnie Wong-Ng, Jeffrey T. Culp, Daniel Siderius, Yu-Sheng Chen, S. Y. G. Wang, Andrew J. Allen, Eric J. Cockayne
Crystal structure of the guest-free Ni(CN)4-based metal organic framework Ni(3-Methy-4,4'-bipyridine)[Ni(CN)4] (nicknamed Ni-BpyMe(A)), was determined to be orthorhombic, Pmma, a= 12.6025(4) Å, b=7.3324(3) Å, c=11.3095(4) Å, V=1045.07 (2) Å3 and Z=2

In situ characterization of ceramic cold sintering by small-angle scattering

January 1, 2021
Author(s)
Andrew J. Allen, Igor Levin, Russell Maier, Suzanne E. Witt, Fan Zhang, Ivan Kuzmenko
The first in situ characterization of the pore morphology evolution during the cold sintering process (CSP) is presented using small-angle X-ray scattering methods. For practical reasons, measurements have been made on a model system, KH2PO4 (KDP). The

Materials Research & Measurement Needs for Ceramics Additive Manufacturing

November 1, 2020
Author(s)
Andrew J. Allen, Igor Levin, Suzanne E. Witt
We report on a recent workshop dedicated to additive manufacturing (AM) of ceramics that was held at the National Institute of Standards and Technology (NIST) in November 2019. This two- day all-invited meeting brought together experts from industry

Early stage nucleation in barium disilicate glass

August 1, 2020
Author(s)
Ling Cai, Randall E. Youngman, David E. Baker, Aram Rezikyan, Minghui Zhang, Bryan Wheaton, Indrajit Dutta, Bruce G. Aitken, Andrew J. Allen
Early stage nucleation in silicate glasses is often evidenced by formation of nanosized regions that are stoichiometrically different from the surrounding matrix. The structural origin of these early stage nucleation sites is of great interest in gaining a

Outcomes and Conclusions from the 2018 AM-Bench Measurements, Challenge Problems, Modeling Submissions, and Conference

February 13, 2020
Author(s)
Lyle E. Levine, Brandon M. Lane, Jarred C. Heigel, Kalman D. Migler, Mark R. Stoudt, Thien Q. Phan, Richard E. Ricker, Maria Strantza, Michael R. Hill, Fan Zhang, Jonathan E. Seppala, Edward J. Garboczi, Erich D. Bain, Daniel Cole, Andrew J. Allen, Jason C. Fox, Carelyn E. Campbell
The Additive Manufacturing Benchmark Test Series (AM-Bench) was established to provide rigorous measurement test data for validating additive manufacturing (AM) simulations for a broad range of AM technologies and material systems. AM-Bench includes

Utica Shale Reactivity: CO2 Induced Pore Scale Changes in the Fracture Network and Matrix

January 3, 2020
Author(s)
Angela Goodman, Sean Sanguinito, Sittichai Natesakhawat, Patricia Cvetic, Barbara Kutchko, Andrew J. Allen
The Utica Shale is expected to be a substantial fossil fuel resource in the future. Currently, 663.5 billion cubic feet of natural gas and oil are being produced from the Utica in Eastern Ohio. In this work, we examined the Utica Shale and its reactivity

Phase Fraction and Evolution of Additively Manufactured 15-5 Stainless Steel and Inconel 625 AM- Benchmark Artifacts

August 5, 2019
Author(s)
Fan Zhang, Lyle E. Levine, Andrew J. Allen, Sandra A. Young, Maureen E. Williams, Mark R. Stoudt, Kil-Won Moon, Jarred C. Heigel, Jan Ilavsky
A proper understanding of the structure and microstructure of additive manufactured (AM) alloys is essential not only to the prediction and assessment of their material properties, but also to the validation and verification of computer models essential to

Disordered Heterogeneous Materials

July 1, 2019
Author(s)
Andrew J. Allen
This chapter describes the use of diffraction-based methods to characterize amorphous or disordered heterogeneous materials. Quantitative materials microstructure characterization using small-angle scattering methods is emphasized. While these techniques

Structural basis of CO2 adsorption in a flexible metal organic framework material

March 4, 2019
Author(s)
Andrew J. Allen, Winnie K. Wong-Ng, Eric J. Cockayne, Jeffrey T. Culp, Christopher Matranga
This paper reports the structural basis of CO2 adsorption in a representative model flexible metal organic framework (MOF) material, Ni(1,2-bis(4-pyridyl)ethylene)[Ni(CN)4] (NiBpene or PICNIC-60). NiBpene exhibits a CO2 sorption isotherm with

Simulation of TTT curves for additively manufactured Inconel 625

January 1, 2019
Author(s)
Carelyn E. Campbell, Greta Lindwall, Eric Lass, Fan Zhang, Mark R. Stoudt, Andrew J. Allen, Lyle E. Levine
The ability to use common computational thermodynamic and kinetic tools to study the microstructure evolution in Inconel 625 (IN625) manufactured using the additive manufacturing (AM) technique of laser powder-bed fusion is evaluated. Solidification