296 research outputs found
Featured Speaker: Dwayne Reed
No full textDwayne Reed is an educator, speaker, author, and rapper. Catapulted by his blockbuster video Welcome to the Fourth Grade, Mr. Reed has been featured on Good Morning America, World News Tonight, BBC News, The Jimmy Kimmel Live Show, and in The Washington Post and Time Magazine. Mr. Reed, an EIU graduate, will share about his teaching journey to guide you on yours
Mt. Hood RSA final report
No full textprepared for: Oregon Department of Transportation (ODOT) ; prepared by: Dwayne Hofstetter, P.E.Title from PDF title page (viewed on December 9, 2019)."Audit Dates: November 16-18, 2011 and February 17, 2012"--Cover.This archived document is maintained by the State Library of Oregon as part of the Oregon Documents Depository Program. It is for informational purposes and may not be suitable for legal purposes.Mode of access: Internet from the Oregon Government Publications Collection.Text in English
Home care workers
No full textby Dwayne Stevenson.Title from PDF caption (viewed on February 24, 2020).Converted from HTML.This archived document is maintained by the State Library of Oregon as part of the Oregon Documents Depository Program. It is for informational purposes and may not be suitable for legal purposes.Mode of access: Internet from the Oregon Government Publications Collection.Text in English
Rapid Acceleration of Hydrogen Atom Abstraction Reactions of OH at Very Low Temperatures through Weakly Bound Complexes and Tunneling
No full textA generally accepted principle of chemical kinetics is that a reaction will be very slow at low temperatures if there is an activation barrier on the potential energy surface to form products. However, this Account shows that the reverse is true for gas-phase hydrogen abstraction reactions of the hydroxyl radical, OH, with organic molecules with which it can form a weakly bound (5–30 kJ mol⁻¹) hydrogen-bonded complex. For hydrogen atom abstraction reactions of OH with volatile organic compounds (VOCs) containing alcohol, ether, carbonyl, and ester functional groups, the reaction accelerates rapidly at very low temperatures, with rate coefficients, k, that can be up to a 1000 times faster than those at room temperature, despite the barrier to products. The OH radical is a crucial intermediate in Earth’s atmosphere, combustion processes, and the chemistry of the interstellar medium, where temperatures can reach as low as 10 K, so this behavior has very important implications for gas-phase chemistry in space. The key point is that at low temperatures the lifetime of the OH–VOC complex against re-dissociation back to reactants becomes much longer, and hence the probability of quantum mechanical tunneling under the reaction barrier to form products becomes much higher.
These observations were made possible by using Laval nozzles to generate uniform supersonic flows at extremely low temperatures so that condensation of the reagents at reactor walls is avoided. In this Account, the use of laser flash-photolysis combined with laser-induced fluorescence spectroscopy within Laval flows is described to study the unusual kinetics of this type of reaction at temperatures down to 21 K and demonstrate the rapid upturn in the rate coefficient. For the reaction of OH with CH₃OH, further evidence for the precomplex and tunneling mechanism comes from observation of the CH₃O reaction product at very low temperatures, despite it being formed over the higher barrier to reaction. The experimental observations are supported by theoretical calculations using the MESMER master equation package to calculate k(T) and product yields as a function of temperature and which make use of potential energy surfaces determined using ab initio methods. The CH₃O product is formed over a narrower barrier with a larger imaginary frequency and is calculated to be the sole product at very low temperatures. The kinetics of the OH reaction with CH₃OH were measured to be independent of pressure, consistent with a tunneling mechanism rather than any collisional stabilization of the prereactive complex. In this Account, we collate available kinetic data and show that this newly discovered mechanism for H atom transfer reactions appears to be generally applicable for reactions of OH with organic molecules containing oxygenated functional groups, which have been observed in space by radio-astronomy. Rather than being ignored for a range of interstellar environments, these OH reactions are now being included in chemical networks in space and have been shown to significantly influence the abundance of OH, the organic molecules themselves, and reaction products and provide novel routes to forming even more complex functional groups, for example, precursors to prebiotic molecules
Metaphor For a Post-White Horizon
No full textThis project is a counternarrative, in the tradition of Richard Delgado’s The Rodrigo Chronicles, using critical race theory’s storytelling methodology. We present a discussion between a Black scholar and white scholar sharing their experiences as they explore the relationship between Blackness/whiteness and anti-Blackness/white supremacy. The crux of this counternarrative lies in the intersection between the hopelessness one Black scholar feels toward racial progress in America and the desperation of a white scholar as they process the possibilities for a post-white ontological future within the Western academy in the wake of the January 6th Insurrection. The counter-story integrates Afropessimistic thought with the creativity of Afrofuturism to comment on the uses and abuses of Black labor under the white gaze. The conclusion of the counter-story argues for the need of a post-white futurism that imagines a possible future without whiteness and a future that is also not subsistent upon the foundational abuse and overuse of Black labor.
Corresponding author information:
Dwayne Kwaysee Wright, J.D., Ph.D., Assistant Professor of Higher Education Administration, The George Washington University, 2136 G Street NW, Room 118, Washington, DC 20052, [email protected], Phone: 347.291.6276
Biographies
Dwayne Kwaysee Wright (he/him/his), J.D., Ph.D. is an Assistant Professor of Higher Education and Director of Diversity, Equity, and Inclusion Initiatives at the Graduate School of Education and Human Development which is part of the George Washington University. His research and social activism seek to advance educational opportunity and equity for all students, particularly those historically oppressed and marginalized in American society.
Email: [email protected]
Dr. Tyler Derreth (he/him/his) is the associate director of SOURCE and faculty in the Department of Health, Behavior, and Society at Johns Hopkins University. His research concentrates on urban community–university partnerships, critical pedagogies, and equitable educational practices. He centers his research agenda on issues of social justice, racism, and identity.
Email: [email protected]
- …
