Engineering topics

Brown, Rebecca

Publications and source records attributed to Brown, Rebecca.

3 records

DOE OSTI2023

SWIFT: Single-pass, Weather Independent Fractionation Technology for Improved Property Control of Corn Stover Feedstock

Corn stover is an abundant source of biomass that can be utilized for bioenergy production, representing 70% of the available crop residues in the U.S. However, recent projections estimate that over 60% of corn stover will be collected at moisture levels that exceed 20% moisture (wet basis), resulting in instability in conventional baled logistics systems due to unwanted microbial degradation. This biomass challenge can be solved with a paradigm-shifting technology or SWIFT: Single-pass, Weather Independent Fractionation Technology. SWIFT streamlines collection by eliminating multiple time-consuming, costly, non-value-added, field and weather-dependent steps that comprise the current state of the art in corn stover harvest. The unique approach envisions simultaneous harvest and collection of high, dry matter, whole-plant corn (i.e., stover plus grain) combined with anaerobic storage and fractionation as a means to positively influence the physical and chemical characteristics of corn stover biomass and the resulting feedstock.

09 BIOMASS FUELS↗

DOE OSTI2021

Surfactant Removal for Colloidal Nanocrystal Catalysts Mediated by N-Heterocyclic Carbenes

In this work, we report the facile removal of surfactants from col-loidally synthesized nanocrystals via a ligand ex-change with N-heterocyclic carbene (NHC). Subse-quent protonation of the NHC ligand in acid efficient-ly cleans the nanocrystal surface while preserving their uniform morphology and structure for catalysis. The broad efficacy of this strategy is validated using monodisperse Pt, Pd, and Au nanocrystals, each pre-pared with strongly bound phosphine stabilizers. The surface activated nanocrystals exhibit signifi-cantly improved catalytic activities, superior to other surface cleaning methods, as demonstrated in two centrally important electrochemical reactions (glyc-erol oxidation and CO 2 reduction). This work high-lights a new surface activation strategy for catalysis and other applications that enables the efficient use of well-defined nanocrystal libraries prepared by colloidal chemistry.

25 ENERGY STORAGE↗

DOE OSTI2020

D614G Spike Mutation Increases SARS CoV-2 Susceptibility to Neutralization

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein acquired a D614G mutation early in the pandemic that confers greater infectivity and is now the globally dominant form. To determine whether D614G might also mediate neutralization escape that could compromise vaccine efficacy, sera from spike-immunized mice, nonhuman primates, and humans were evaluated for neutralization of pseudoviruses bearing either D614 or G614 spike. In all cases, the G614 pseudovirus was moderately more susceptible to neutralization. The G614 pseudovirus also was more susceptible to neutralization by receptor-binding domain (RBD) monoclonal antibodies and convalescent sera from people infected with either form of the virus. Here, negative stain electron microscopy revealed a higher percentage of the 1-RBD “up” conformation in the G614 spike, suggesting increased epitope exposure as a mechanism of enhanced vulnerability to neutralization. Based on these findings, the D614G mutation is not expected to be an obstacle for current vaccine development.

60 APPLIED LIFE SCIENCES↗