Characterizing students' intercultural competence development paths through a global engineering program

Global competence is increasingly recognized as an important skill for engineering students to develop in preparation for their entrance into the engineering workforce [1], [2]. A variety of global engineering programs have been developed to achieve this goal [3], and several studies have assessed the outcomes of such programs [1]. To date, literature on global engineering programs has emphasized program overviews and assessment of student learning outcomes. Although outcomes-based assessment is important for the continuous improvement of such programs, recent critiques of global education research suggest that another perspective is missing from the literature [4]. Few studies explore student conceptions of their global programs and how students may experience the same program in different ways. Understanding variation in students’ experiences is important to developing effective global programs, particularly as educators seek to improve the diversity of such programs. To address this need, our study piloted a fully-integrated complementary mixed-methods approach to identify and characterize unique student paths through a single global engineering program

Chlorine-Induced Degradation in Solid Oxide Fuel Cells Identified by <i>Operando</i> Optical Methods

Chlorine in the form of HCl or CH₃Cl can accelerate degradation of solid oxide fuel cell (SOFC) Ni-based anodes through several proposed mechanisms. However, many of these mechanisms were developed with H₂ as the primary SOFC fuel, and the effects of chlorine on SOFC anodes operating with carbon containing fuels have not been studied in detail. Experiments described in this work use a suite of independent, complementary techniques to examine chlorine-induced degradation of a SOFC operating with methane at 700 °C. <i>Operando</i> Raman and FTIR-emission spectroscopy, electrochemical characterization, and near-IR thermal imaging coupled with <i>ex-situ</i> field emission scanning electron microscopy provide interlocking data that illustrate how chlorine inhibits CH₄ activation on the anode’s Ni catalyst. Raman spectroscopy is used to monitor carbon formation (a signature of methane cracking), while the SOFC is exposed to 100 ppm chlorine and intermittently exposed to methane for 10 min intervals. Linear scan voltammetry (LSV) and electrochemical impedance spectroscopy (EIS) show marked degradation, while both carbon accumulation and <i>P</i>_CO2 above the anode decrease. Compared to degradation rates in SOFCs exposed to chlorine and operating with hydrogen, degradation with methane is greatly accelerated. Additional differences between SOFCs operating with hydrogen and methane are observed in their ability to recover performance after chlorine is removed from the incident fuel

Intramolecular Charge-Assisted Hydrogen Bond Strength in Pseudochair Carboxyphosphate

Carboxyphosphate, a suspected intermediate in ATP-dependent carboxylases, has not been isolated nor observed directly by experiment. Consequently, little is known concerning its structure, stability, and ionization state. Recently, carboxyphosphate as either a monoanion or dianion has been shown computationally to adopt a novel pseudochair conformation featuring an intramolecular charge-assisted hydrogen bond (CAHB). In this work, additive and subtractive correction schemes to the commonly employed open–closed method are used to estimate the strength of the CAHB. Truhlar’s Minnesota M06-2X functional with Dunning’s aug-cc-pVTZ basis set has been used for geometry optimization, energy evaluation, and frequency analysis. The CHARMM force field has been used to approximate the Pauli repulsive terms in the closed and open forms of carboxyphosphate. From our additive correction scheme, differential Pauli repulsion contributions between the pseudochair (closed) and open conformations of carboxyphosphate are found to be significant in determining the CAHB strength. The additive correction modifies the CAHB prediction (Δ<i>E</i>_{closed–open}) of −14 kcal/mol for the monoanion and −12 kcal/mol for the dianion to −22.9 and −18.4 kcal/mol, respectively. Results from the subtractive technique reinforce those from our additive procedure, where the predicted CAHB strength ranges from −17.8 to −25.4 kcal/mol for the monoanion and from −15.7 to −20.9 kcal/mol for the dianion. Ultimately, we find that the CAHB in carboxyphosphate meets the criteria for short-strong hydrogen bonds. However, carboxyphosphate has a unique energy profile that does not result in the symmetric double-well behavior of low-barrier hydrogen bonds. These findings provide deeper insight into the pseudochair conformation of carboxyphosphate, and lead to an improved mechanistic understanding of this intermediate in ATP-dependent carboxylases