Rice University Research Repository
The Rice Research Repository (R-3) provides access to research produced at Rice University, including theses and dissertations, journal articles, research center publications, datasets, and academic journals. Managed by Fondren Library, R-3 is indexed by Google and Google Scholar, follows best practices for preservation, and provides DOIs to facilitate citation. Woodson Research Center collections, including Rice Images and Documents and the Task Force on Slavery, Segregation, and Racial Injustice, have moved here.
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Nano-sized boron-doped diamond (BDD) enabled electrodes
(2024-09-17) Westerhoff, Paul K.; Garcia-segura, Sergio; Sinha, Shahnawaz; Bansal, Rishabh; Verduzco, Rafael; Wong, Michael S.; Rice University; Arizona Board of Regents on behalf of Arizona State University; United States Patent and Trademark Office
An electrode includes an electrically conductive substrate with a coating containing boron-doped diamond (BDD) nanoparticles. Fabricating the electrode can include dispersing BDD nanoparticles in a solvent to yield a suspension, coating a conductive substrate with the suspension, and drying the suspension to yield the electrode. In some cases, fabricating the electrode includes combining BDD nanoparticles with a polymeric resin precursor to yield a mixture including a metal oxide, coating a conductive substrate with the mixture to yield a coated substrate, and calcining the coated substrate to yield a metal oxide coating including BDD nanoparticles. In certain cases, fabricating the electrode includes combining powdered activated carbon with polymeric linkers to yield a polymeric precursor solution, combining BDD nanoparticles with the polymeric precursor solution to yield a mixture, coating a conductive substrate with the mixture to yield a coated substrate, and crosslinking the polymeric linkers to yield the electrode.
Anodes, cathodes, and separators for batteries and methods to make and use same
(2024-09-10) Tour, James M.; Salvatierra, Rodrigo Villegas; Silva, Gladys Anahi Lopez; Rice University; United States Patent and Trademark Office
Anodes, cathodes, and separators for batteries (electrochemical energy storage devices). The anodes are Li metal anodes having lithiated carbon films (Li-MWCNT) (as dendrite suppressors and protective coatings for the Li metal anodes). The cathodes are sulfurized carbon cathodes. The separators are GNR-coated (or modified) separators. The invention includes each of these separately (as well as in combination both with each other and with other anodes, cathodes, and separators) and the methods of making each of these separately (and in combination). The invention further includes a battery that uses at least one of (a) the anode having a lithiated carbon film, (b) the sulfurized carbon cathode, and (c) the GNR-modified separator in the anode/cathode/separator arrangement. For instance, a full battery can include the sulfurized carbon cathode in combination with the Li-MWCNT anode or a full battery can include the sulfurized carbon cathode in combination with other anodes (such as a GCNT-Li anode).
Advanced Methods for Analyzing in-Situ Observations of Magnetic Reconnection
(Springer Nature, 2024) Hasegawa, H.; Argall, M. R.; Aunai, N.; Bandyopadhyay, R.; Bessho, N.; Cohen, I. J.; Denton, R. E.; Dorelli, J. C.; Egedal, J.; Fuselier, S. A.; Garnier, P.; Génot, V.; Graham, D. B.; Hwang, K. J.; Khotyaintsev, Y. V.; Korovinskiy, D. B.; Lavraud, B.; Lenouvel, Q.; Li, T. C.; Liu, Y.-H.; Michotte de Welle, B.; Nakamura, T. K. M.; Payne, D. S.; Petrinec, S. M.; Qi, Y.; Rager, A. C.; Reiff, P. H.; Schroeder, J. M.; Shuster, J. R.; Sitnov, M. I.; Stephens, G. K.; Swisdak, M.; Tian, A. M.; Torbert, R. B.; Trattner, K. J.; Zenitani, S.; Rice Space Institute
There is ample evidence for magnetic reconnection in the solar system, but it is a nontrivial task to visualize, to determine the proper approaches and frames to study, and in turn to elucidate the physical processes at work in reconnection regions from in-situ measurements of plasma particles and electromagnetic fields. Here an overview is given of a variety of single- and multi-spacecraft data analysis techniques that are key to revealing the context of in-situ observations of magnetic reconnection in space and for detecting and analyzing the diffusion regions where ions and/or electrons are demagnetized. We focus on recent advances in the era of the Magnetospheric Multiscale mission, which has made electron-scale, multi-point measurements of magnetic reconnection in and around Earth’s magnetosphere.
Evaluation of finite element modeling methods for predicting compression screw failure in a custom pelvic implant
(Frontiers Media S.A., 2024) Zhu, Yuhui; Babazadeh-Naseri, Ata; Brake, Matthew R. W.; Akin, John E.; Li, Geng; Lewis, Valerae O.; Fregly, Benjamin J.
Introduction: Three-dimensional (3D)-printed custom pelvic implants have become a clinically viable option for patients undergoing pelvic cancer surgery with resection of the hip joint. However, increased clinical utilization has also necessitated improved implant durability, especially with regard to the compression screws used to secure the implant to remaining pelvic bone. This study evaluated six different finite element (FE) screw modeling methods for predicting compression screw pullout and fatigue failure in a custom pelvic implant secured to bone using nine compression screws. Methods: Three modeling methods (tied constraints (TIE), bolt load with constant force (BL-CF), and bolt load with constant length (BL-CL)) generated screw axial forces using functionality built into Abaqus FE software; while the remaining three modeling methods (isotropic pseudo-thermal field (ISO), orthotropic pseudo-thermal field (ORT), and equal-and-opposite force field (FOR)) generated screw axial forces using iterative physics-based relationships that can be implemented in any FE software. The ability of all six modeling methods to match specified screw pretension forces and predict screw pullout and fatigue failure was evaluated using an FE model of a custom pelvic implant with total hip replacement. The applied hip contact forces in the FE model were estimated at two locations in a gait cycle. For each of the nine screws in the custom implant FE model, likelihood of screw pullout failure was predicted using maximum screw axial force, while likelihood of screw fatigue failure was predicted using maximum von Mises stress. Results: The three iterative physics-based modeling methods and the non-iterative Abaqus BL-CL method produced nearly identical predictions for likelihood of screw pullout and fatigue failure, while the other two built-in Abaqus modeling methods yielded vastly different predictions. However, the Abaqus BL-CL method required the least computation time, largely because an iterative process was not needed to induce specified screw pretension forces. Of the three iterative methods, FOR required the fewest iterations and thus the least computation time. Discussion: These findings suggest that the BL-CL screw modeling method is the best option when Abaqus is used for predicting screw pullout and fatigue failure in custom pelvis prostheses, while the iterative physics-based FOR method is the best option if FE software other than Abaqus is used.
Are the geographic disparities in U.S. violent crime rising?
(Public Library of Science, 2024) Boylan, Richard T.
Inequality in economic and social outcomes across U.S. regions has grown in recent decades. The economic theory of crime predicts that this increased variability would raise geographic disparities in violent crime. Instead, I find that geographic disparities in homicide rates decreased. Moreover, these same decades saw decreases in the geographic disparities in policing, incarceration, and the share of the population that is African American. Thus, changes in policing, incarcerations, and racial composition could have led to a decrease in inequality in homicide rates. Moreover, the joint provision of law enforcement by local, state, and federal authorities may have reduced the impact of economic distress on violent crime.