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The influence of the amine structure (secondary, tertiary, pyridinic) in amine-functionalized polymeric membranes on the mechanism of CO2 transport across the membrane is investigated in this work using operando surface enhanced Raman spectroscopy (SERS) and in-situ transmission FTIR spectroscopy. Specifically, the mechanism of CO2 transport across poly-N-methyl-N-vinylamine (PMVAm), poly-N, N-dimethyl-N-vinylamine (PDVAm), and poly(4-vinylpyridine) (P4VP) membranes was investigated by measuring CO2 permeances/selectivities of the membranes and simultaneously detecting CO2 transport intermediates (e.g., carbamate, bicarbonate) formed in the membrane under operating conditions using SERS and FTIR spectroscopy. While permeation measurements suggest that CO2 moves across all membranes via a facilitated transport mechanism, operando SERS and in-situ FTIR results suggest that the molecular-level details of the facilitated transport process are highly sensitive to the structure of the amine functional group. For membranes with secondary (PMVAm) and tertiary (PDVAm) amines, CO2 moves across the membrane as a mixture of both carbamate and bicarbonate species. For P4VP, which has pyridinic amine groups, no CO2-derived intermediates were detected suggesting a new facilitated transport mechanism involving weak interactions between CO2 and the pyridinic nitrogen group without transformation of CO2 into carbamate, bicarbonate, or other intermediate species. Such a facilitated transport mechanism has not been reported in the literature to our knowledge. 

Understanding the catalytic oxidation of propane is important for developing catalysts not only for catalytic oxidation of hydrocarbons in emission systems but also for selective oxidation in the chemical processing industry. For palladium-based catalysts, little is known about the identification of the chemical or intermediate species involved in propane oxidation. We describe herein findings of an investigation of the catalytic oxidation of propane over supported palladium nanoalloys with different compositions of gold (Pd n Au 100−n ), focusing on probing the chemical or intermediate species on the catalysts in correlation with the bimetallic composition and the alloying phase structure. In addition to an enhanced catalytic activity, a strong dependence of the catalytic activity on the bimetallic composition was revealed, displaying an activity maximum at a Pd : Au ratio of 50 : 50 in terms of reaction temperature. This dependence is also reflected by its dependence on the thermochemical treatment conditions. While the activity for nanoalloys with n ∼ 50 showed little change after the thermochemical treatment under oxygen, the activities for nanoalloys with n < 50 and n > 50 showed opposite trends. Importantly, this catalytic synergy is linked to the subtle differences of chemical and intermediate species which have been identified for the catalysts with different bimetallic compositions by in situ measurements using diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). For the catalytic oxidation of propane over the highly-active catalyst with a Pd : Au ratio of 50 : 50, the major species identified include acetate and bicarbonate, showing subtle differences in comparison with the identification of bicarbonate and formate for the catalyst with <50% Au (with a lower activity) and the absence of apparent species for the catalyst with >50% Au (activity is largely absent). The alloying of 50% Au in Pd is believed to increase the oxophilicity of Pd, which facilitates the first carbon–carbon bond cleavage and oxygenation of propane. The implications of the findings on the catalytic synergy of Pd alloyed with Au and the design of active Pd alloy catalysts are also discussed. 

For the third consecutive year, Scholarship for Service (SFS) scholars at the University of Maryland, Baltimore County (UMBC) analyzed the security of targeted portions of the UMBC computer systems. During these hands-on studies, with complete access to sourcecode, students identified vulnerabilities, devised and implemented exploits, and recommended mitigations. We report on our continuing experiences with these project-based learning studies, focusing on the new problems addressed in January 2018 and 2019 and on the lessons we learned. In 2018, students analyzed the WebAdmin custom software that UMBC students, faculty, and staff use to manage credentials and accounts. Students found a beautifully instructive example of a “confused-deputy attack,” wherein an IT staff member—–through carrying out their proper procedures for resetting a user password—–unwittingly executes malware on their own machine by viewing the answers to security questions. In 2019, students analyzed the Virthost system UMBC uses to host student webpages. Organizer Alan Sherman created a powerful learning experience by secretly recruiting one of the participants to serve as a “mole,” passively collecting passwords from the other participants throughout the week. Our students found the collaborative experiences inspirational; students and educators appreciated the authentic case studies; and IT administrators gained access to future employees and received free recommendations for improving the security of their systems.