Jon Secrest and Cindy Fuller in a Faculty Recital

This is the program for the faculty recital featuring tenor Jon Secrest and pianist Cindy Fuller. This recital took place on September 25, 2001, in the W. Francis McBeth Recital Hall

Glenda Secrest, Jon Secrest, and Cindy Fuller in a Faculty Recital

This is the program for the faculty recital featuring soprano Glenda Secrest, tenor Jon Secrest, and pianist Cindy Fuller. This recital took place on September 25, 2003, in the W. Francis McBeth Recital Hall

A Performing Arts Class Faculty Recital

This is the program for the Performing Arts Class faculty recital performance. The following faculty artists performed (in order of performance): trumpet player Doug Lockard; soprano Cindy Fuller accompanied by pianist Becky Moore; tenor Jon Secrest accompanied by pianist Cindy Fuller; tenor Stephen Garner accompanied by pianist Ouida Keck; duo pianists Cindy Fuller and Becky Moore; flutist Barry McVinney and organist Russell Hodges; and organist Russell Hodges. This recital took place on September 19, 1997, in the W. Francis McBeth Recital Hall

Reaction mechanism and kinetics for ammonia synthesis on the Fe(211) reconstructed surface

To provide guidelines to accelerate the Haber–Bosch (HB) process for synthesis of ammonia from hydrogen and nitrogen, we used Quantum Mechanics (QM) to determine the reaction mechanism and free energy reaction barriers under experimental reaction conditions (400 °C and 20 atm) for all 10 important surface reactions on the Fe(211) reconstructed (Fe(211)R) surface. These conditions were then used in full kMC modeling for 30 minutes to attain steady state. We find that the stable surface under Haber–Bosch conditions is the missing row 2 × 1 reconstructed surface (211)R and that the Turn Over Frequency (TOF) is 18.7 s^(−1) per 2 × 2 surface site for 1.5 Torr NH_3 pressure, but changes to 3.5 s^(−1) for 1 atm, values close (within 6%) to the ones on Fe(111). The experimental ratio between (211) and (111) rates at low (undisclosed) NH_3 pressure was reported to be 0.75. The excellent agreement with experiment on two very different surfaces and reaction mechanisms is a testament of the accuracy of QM modeling. In addition, our kinetic analysis indicates that Fe(211)R is more active than Fe(111) at high pressure, close to HB industrial conditions, and that (211)R is more abundant than (111) via a steady-state Wulff construction under HB conditions. Thus, at variance with common thinking, we advocate the Fe(211)R surface as the catalytically active phase of pure iron ammonia synthesis catalyst under HB industrial conditions

Discovery of Dramatically Improved Ammonia Synthesis Catalysts through Hierarchical High-Throughput Catalyst Screening of the Fe(211) Surface

In order to improve efficiency of ammonia synthesis using the Haber–Bosch (HB) process with Fe-based catalysts, we employed quantum mechanics (QM)-based hierarchical high-throughput catalyst screening (HHTCS) of 49 possible metal dopants. Here, we consider the Fe(211) surface (one of the two most active iron catalyst facets) to identify dopants that dramatically increase the turnover frequency (TOF) for HB synthesis. We found that under HB conditions, this surface reconstructs to form the Fe(211)R missing-row surface. Focusing on dopants with a strong preference for the subsurface site, we found that Co is the most promising candidate among the 49. We then examined the full reaction pathway on this Co-doped Fe(211)R surface, considering all 19 important 2 × 2 configurations and calculated the free-energy barriers (ΔG∫) for all 12 important reaction steps. At 673 K and 20 atm, we find a decrease, δ(ΔG∫) = −0.19 eV, in the overall reaction free-energy barrier for the Co-doped case. We then carried out kinetic Monte Carlo simulations for 60–120 min using 100 replicas with the full reaction path using rates from QM free-energy reaction barriers to predict that the TOF for the Co-doped surface increases by a factor of 2.8 with respect to the undoped Fe(211)R surface. Thus, the Co-doped Fe(211)R system could lower the extreme HB pressure of 200 atm to ∼40 atm at 773 K while maintaining the same TOF as that of undoped Fe(211)R. We conclude that Co dopants in the Fe catalyst could significantly improve the catalytic efficiency of ammonia synthesis under industrial conditions. This excellent performance of the Co-doped system is explained in terms of a surface spin analysis on the N₂-bonded configurations that show how Co dopants shift the N₂ surface-binding mode. This demonstrates that metal surface spins can be used as quantitative descriptors to understand reaction energetics. This study demonstrates that the HHTCS kinetic analysis of the free-energy reaction path in terms of essential configurations can enable discovery of the salient barriers to overcome and best dopant candidates for further improvements

Highly Efficient Ni-Doped Iron Catalyst for Ammonia Synthesis from QM-Based Hierarchical High Throughput Catalyst Screening

To discover more efficient industrial catalysts for ammonia synthesis via the Haber–Bosch (HB) process, we employed quantum mechanics (QM)-based hierarchical high-throughput catalyst screening (HHTCS) to test a wide group of elements (34) as candidates to dope the Fe(111) catalyst subsurface. The QM free-energy reaction network of HB over Fe(111) yields ten barriers as potentially rate-determining, of which we select four as prototypical, arrange them hierarchically, and define a corresponding set of screening criteria, which we then use to screen candidate catalysts. This leads to two promising candidates (Co and Ni), from which we selected the most promising (Ni) for a complete QM and kinetic study. The kinetic Monte Carlo (kMC) simulations predict a 16-fold increase in HB turn-over frequency (TOF) for the Ni-doped catalyst compared to the pure Fe(111) surface under realistic conditions. The 16-fold increase in HB TOF is a significant improvement and may trigger future experimental studies to validate our prediction. This TOF improvement could lead to similar reaction rates as with pure Fe but at a reaction temperature decreased by 100° from 773 to 673 K and a total reactant pressure decreased by 6 times from 201 to 34 atm. We interpret the reasons underlying this improvement using valence bond and kinetic analyses. We suggest this Ni-doped Fe(111) catalyst as a candidate to reduce the world energy consumption for the HB process while satisfying future needs for energy and environment

Theology, News and Notes - Vol. 28, No. 02

Theology News & Notes was a theological journal published by Fuller Theological Seminary from 1954 through 2014.https://digitalcommons.fuller.edu/tnn/1074/thumbnail.jp

Ecological consequences of human niche construction: Examining long-term anthropogenic shaping of global species distributions

The exhibition of increasingly intensive and complex niche construction behaviors through time is a key feature of human evolution, culminating in the advanced capacity for ecosystem engineering exhibited by Homo sapiens. A crucial outcome of such behaviors has been the dramatic reshaping of the global biosphere, a transformation whose early origins are increasingly apparent from cumulative archaeological and paleoecological datasets. Such data suggest that, by the Late Pleistocene, humans had begun to engage in activities that have led to alterations in the distributions of a vast array of species across most, if not all, taxonomic groups. Changes to biodiversity have included extinctions, extirpations, and shifts in species composition, diversity, and community structure. We outline key examples of these changes, highlighting findings from the study of new datasets, like ancient DNA (aDNA), stable isotopes, and microfossils, as well as the application of new statistical and computational methods to datasets that have accumulated significantly in recent decades. We focus on four major phases that witnessed broad anthropogenic alterations to biodiversity—the Late Pleistocene global human expansion, the Neolithic spread of agriculture, the era of island colonization, and the emergence of early urbanized societies and commercial networks. Archaeological evidence documents millennia of anthropogenic transformations that have created novel ecosystems around the world. This record has implications for ecological and evolutionary research, conservation strategies, and the maintenance of ecosystem services, pointing to a significant need for broader cross-disciplinary engagement between archaeology and the biological and environmental sciences