Directional Statistics of Preferential Orientations of Two Shapes in Their Aggregate and Its Application to Nanoparticle Aggregation
Abstract
Nanoscientists have long conjectured that adjacent nanoparticles aggregate with one another in certain preferential directions during chemical syntheses of nanoparticles, which is so called the oriented attachment. For the study of the oriented attachment phenomenon, the microscopy and nanoscience community have used dynamic electron microscopy for direct observations of nanoparticle aggregation and have been so far relying on the manual and qualitative analysis of the observations. In this paper, we present a statistical approach for studying the oriented attachment phenomenon with multiple aggregation examples observed by dynamic microscope data. We abstract a nanoparticle aggregation by an event of two primary geometric objects merging into a secondary geometric object. We define a metric space for geometrical bodies, and the endowed metric in the space allows us to define the likelihood function of the orientation angles of two primary objects within the corresponding secondary object. We maximize the likelihood to estimate the orientation angles. We fit a mixture of bivariate von Mises distributions to the estimated orientation angles for the density estimation. By analyzing the density estimate, we are able to demonstrate that nanoparticles of certain geometries have indeed preferential orientations in their aggregates.
 Authors:

 Florida State University
 UNIVERSITY OF CALIFORNIA, DAVIS
 University of California, Davis
 BATTELLE (PACIFIC NW LAB)
 Publication Date:
 Research Org.:
 Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
 Sponsoring Org.:
 USDOE
 OSTI Identifier:
 1527008
 Report Number(s):
 PNNLSA110076
 DOE Contract Number:
 AC0576RL01830
 Resource Type:
 Journal Article
 Journal Name:
 Technometrics
 Additional Journal Information:
 Journal Volume: 60; Journal Issue: 3
 Country of Publication:
 United States
 Language:
 English
 Subject:
 Mixture of bivariate von Mises distributions, Biangular data, Euclidean distancebased
Citation Formats
Sikaroudi, Ali E., Welch, David A., Woehl, Taylor J., Faller, Roland, Evans, James E., Browning, Nigel D., and Park, Chiwoo. Directional Statistics of Preferential Orientations of Two Shapes in Their Aggregate and Its Application to Nanoparticle Aggregation. United States: N. p., 2018.
Web. doi:10.1080/00401706.2017.1366949.
Sikaroudi, Ali E., Welch, David A., Woehl, Taylor J., Faller, Roland, Evans, James E., Browning, Nigel D., & Park, Chiwoo. Directional Statistics of Preferential Orientations of Two Shapes in Their Aggregate and Its Application to Nanoparticle Aggregation. United States. doi:10.1080/00401706.2017.1366949.
Sikaroudi, Ali E., Welch, David A., Woehl, Taylor J., Faller, Roland, Evans, James E., Browning, Nigel D., and Park, Chiwoo. Mon .
"Directional Statistics of Preferential Orientations of Two Shapes in Their Aggregate and Its Application to Nanoparticle Aggregation". United States. doi:10.1080/00401706.2017.1366949.
@article{osti_1527008,
title = {Directional Statistics of Preferential Orientations of Two Shapes in Their Aggregate and Its Application to Nanoparticle Aggregation},
author = {Sikaroudi, Ali E. and Welch, David A. and Woehl, Taylor J. and Faller, Roland and Evans, James E. and Browning, Nigel D. and Park, Chiwoo},
abstractNote = {Nanoscientists have long conjectured that adjacent nanoparticles aggregate with one another in certain preferential directions during chemical syntheses of nanoparticles, which is so called the oriented attachment. For the study of the oriented attachment phenomenon, the microscopy and nanoscience community have used dynamic electron microscopy for direct observations of nanoparticle aggregation and have been so far relying on the manual and qualitative analysis of the observations. In this paper, we present a statistical approach for studying the oriented attachment phenomenon with multiple aggregation examples observed by dynamic microscope data. We abstract a nanoparticle aggregation by an event of two primary geometric objects merging into a secondary geometric object. We define a metric space for geometrical bodies, and the endowed metric in the space allows us to define the likelihood function of the orientation angles of two primary objects within the corresponding secondary object. We maximize the likelihood to estimate the orientation angles. We fit a mixture of bivariate von Mises distributions to the estimated orientation angles for the density estimation. By analyzing the density estimate, we are able to demonstrate that nanoparticles of certain geometries have indeed preferential orientations in their aggregates.},
doi = {10.1080/00401706.2017.1366949},
journal = {Technometrics},
number = 3,
volume = 60,
place = {United States},
year = {2018},
month = {5}
}