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ABSTRACT: We have established an ambient temperature, one-pot, acid-catalyzed, three-component process involving in situ formation of a tetrayne or triyne that spontaneously cyclizes to a benzyne intermediate. This is rapidly captured to give a diverse range of polycyclic phthalan derivatives. Product structural diversity was enhanced by employing various combinations of alkyne substrates and benzyne trapping reagents. This cascade reaction is versatile and efficient and can be effected by a variety of Lewis and Brønsted acid catalysts. Success in an aqueous or even solvent-free environment was demonstrated. 

This paper develops a framework to extend the strategic form analysis of cursed equilibrium (CE) developed by Eyster and Rabin (2005) to multistage games. The approach uses behavioral strategies rather than normal form mixed strategies and imposes sequential rationality. We define and characterize properties of cursed sequential equilibrium (CSE) and apply it to four canonical economic applications: signaling games, reputation building, durable goods monopoly, and the dirty faces game. These applications illustrate various implications of CSE, show how and why it differs from sequential equilibrium and CE, and provide evidence from laboratory experiments that support the empirical relevance of CSE. (JEL C72, C73, D42, D82, D83) 

The ability to apply data-driven design principles to customize new CI investment to best serve the intended community as well as provide fact-based justification for its need is critical given the important role it plays in research and economic development and its high cost. Here we describe a data driven approach to CI sys- tem design based on workload analyses obtained using the popular open-source CI management tool Open XDMoD, and how it was leveraged in a procurement to provide end-users with an additional 5.6 million CPU hours annually, with subsequent procurements following similar design goals. In addition to system design, we demonstrate Open XDMoD’s utility in providing fact-based justifi- cation for the CI procurement through usage metrics of existing CI resources. 

Engineering education is typically described using a “pipeline” metaphor, wherein students are shuffled along pre-determined pathways toward a narrow set of career outcomes. However, several decades of research have shown that this pipeline model does not accurately describe engineering trajectories and may exclude students who enter the pipeline at different times and have other career outcomes in mind. Similarly, qualitative studies have shown that normative identities in engineering feature masculine stereotypes such as “geeks” and “nerds” that reproduce technical/social dichotomies. Several studies have suggested that broadening the expected outcomes and identities in engineering to include “alternative” pathways and identities may contribute to a shift to a more inclusive form of engineering education. To make these alternative pathways more visible to faculty and students, we have developed a set of engineering “personas” based on interviews [n=16] with senior engineering students at a liberal arts university. Interviews were coded by three members of the research team using consensus coding techniques to ascertain core elements of the personas: Origins, Identities, and Trajectories. Early drafts of student personas were presented to students, who provided insights into future iterations. We propose several engineering personas using a matrix approach, which allows each persona to be adaptable for various origins, identities, and trajectories. These personas contribute to our understanding of alternative engineering pathways based on real student experiences. We intend to use these personas as pedagogical tools to help faculty recognize a wider range of engineering identities, and to help students see themselves as “real engineers” without sacrificing other (non-technical) core values, identities, and pathways. 

Abstract Volcano-sedimentary lithium (Li) deposits are a potential source of battery-grade Li, although the important factors controlling Li enrichment in these systems remain unclear. At Thacker Pass in Nevada, high-grade mineralization overprinted intracaldera lacustrine claystone made of authigenic Li-rich smectite with bulk grades of ~3,000 ppm Li, converting it to illitic claystone with grades of ~6,000 ppm Li. Some attribute this enrichment to burial diagenesis, whereas others propose lacustrine Li enrichment through leaching and climate-driven evapoconcentration enhanced by postdepositional hydrothermal alteration. To better understand Li enrichment in volcano-sedimentary systems, claystones from throughout Thacker Pass were analyzed using powder X-ray diffraction (PXRD), electron microprobe (EPMA), laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS), and stable isotope (clay δ18O, δ17O, and δ2H and carbonate δ13C and δ18O) methods. Compositional data suggest that illitization is required to achieve clay Li grades above ~0.9 wt % in Mg silicate clays because of a charge-coupled substitution that requires filling interlayer vacancies with K. Clay chemical trends and computational modeling exercises also suggest that F may be important in the formation of Li-rich clays by lowering kinetic barriers to clay precursor growth and illitization. The results are incompatible with diagenetic smectite/illite formation but are consistent with a model wherein authigenic smectite was subjected to hydrothermal alteration in the presence of a K-, Li-, and F-rich fluid that permeated the stratigraphy through a network of normal faults associated with caldera resurgence. These results also enhance our understanding of Li clay formation in other volcano-sedimentary systems. 

Prior studies of halobenzene−ammonia complexes have shown that the nature of the cationic intermediate (i.e., Wheland-type vs ion-radical) may play a key role in determining the reaction products. To probe this link, we report here the reaction dynamics of the chlorobenzene-ammonia 1:1 complex (PhCl···NH3) using product ion imaging following two-color resonant two-photon ionization. A threshold value of 8.863 ± 0.008 eV was determined for the appearance of protonated aniline, which accompanies Cl atom loss and is the dominant product channel at energies near threshold. Scanning down to energies close to threshold, we find no evidence for a roaming halogen radical mechanism leading to HCl products, which was evidenced in the related bromobenzene−ammonia complex, and proceeded through an ion-radical intermediate structure. Here, supporting calculations indicate that both types of intermediates are present, but the Wheland-type structure is significantly more stable. Addressing a key question of earlier work, analysis of the PhCl···NH3 potential energy surface (PES) in the reactant region establishes a complicated entrance channel pathway linking the in-plane σ-type complex to the Wheland intermediate (iWH) on the [PhCl···NH3]+• cationic surface. This pathway involves stepwise transition of the weakly bound ammonia from the initial in-plane σ-type complex to an ortho Wheland intermediate, followed by rearrangement to the ipso position. Finally, given that fluorine has been shown to stabilize aromatic ions, we hypothesized that fluorine substitution might alter the structure of the intermediate, favoring the ion-radical intermediate. To test this hypothesis, as an illustrative example the PES of the meta-PhClF-NH3 system on the cationic surface was computed. Confirming our hypothesis, these calculations show an inversion in stability for the Wheland-type and ion−radical complex intermediates, with the latter preferred energetically at the examined level of theory. 

This paper addresses the theme of “the Moral and Ethical Responsibility of Engineers and Engineering”, particularly responding to the question of how to define or deliberate the meaning of ‘public welfare’ and ‘common good’ in engineering degree programs. Drawing from decades of international work on human development, particularly in the global south, this paper reports on adapting the capability approach to an engineering degree program. Developed by Amartya Sen, the capability approach sought to replace GDP-based models of welfare economics by framing the goal of development as enabling individuals to live a life they value. The things a person values, what they are and can do (determined by their opportunities, experiences, and cultural affordances) are their ‘functionings’. In Sen’s framework each individual has a unique ‘functionings vector’ based on what they value. Although someone’s functionings vector indicates valued goals, they will be unsuccessful in achieving their goals unless they have access to needed resources, can effectively utilize those resources, possess agency, and have the ‘capability’ to enact the functionings. ‘Capabilities’ determine the set of functionings that are actually available to a person. Although rarely used in engineering, the capability approach offers a mature and well-developed framework to address issues of public welfare. Public good is defined through an individual’s freedom to pursue a life they have reason to value, and such freedom defines both the means and end of development. The role of engineering in society—primarily through development of infrastructure—is to support equitable access to capabilities for all individuals. Through support of an NSF Revolutionizing Engineering Departments (RED) grant, an ECE department in a mid-Atlantic liberal arts university has adapted the capability approach to inform change in an undergraduate degree program. Specific examples from four years of implementation are shared. 

Abstract Weakened magnetic braking (WMB) was originally proposed in 2016 to explain anomalously rapid rotation in old field stars observed by the Kepler mission. The proximate cause was suggested to be a transition in magnetic morphology from larger to smaller spatial scales. In a series of papers over the past 5 yr, we have collected spectropolarimetric measurements to constrain the large-scale magnetic fields for a sample of stars spanning this transition, including a range of spectral types from late F to early K. During this time, we gradually improved our methods for estimating the wind braking torque in each of our targets, and for evaluating the associated uncertainties. Here, we reanalyze the entire sample with a focus on uniformity for the relevant observational inputs. We supplement the sample with two additional active stars to provide more context for the evolution of wind braking torque with stellar Rossby number (Ro). The results demonstrate unambiguously that standard spin-down models can reproduce the evolution of wind braking torque for active stars, but WMB is required to explain the subsequent abrupt decrease in torque as Ro approaches a critical value for dynamo excitation. This transition is seen in both the large-scale magnetic field and the X-ray luminosity, indicating weakened coronal heating. We interpret these transitions as evidence of a rotational threshold for the influence of Coriolis forces on global convective patterns and the resulting inefficiency of the global stellar dynamo. 

Traditional engineering curriculum and course structures prioritize preparing students for technical and logical reasoning skills that are intrinsic to becoming an engineer. While these skills are undeniably vital for an engineering career, these courses often fail to provide opportunities for students to explore skills that go beyond the traditional curriculum and classroom walls. In addition, course structures often reinforce the stereotypical narrative in engineering that there is a dichotomy between the social and technical aspects with the latter being more important. Preparing students for both social and technical sides of engineering, requires a reorganization of how learning environments are designed and how engineering programs and faculty evaluate how learning occurs.