Sphere Encapsulated Monte Carlo: Obtaining Minimum Energy Configurations of Large Aromatic Systems.

We introduce a simple global optimization approach that is able to find minimum energy configurations of clusters containing aromatic molecules. The translational and rotational perturbations required in Monte Carlo-based methods often lead to unrealistic configurations within which two or more molecular rings intersect, causing many of the computational steps to be rejected and the optimization process to be inefficient. Here we develop a modification of the basin-hopping global optimization procedure tailored to tackle problems with intersecting molecular rings. Termed the Sphere Encapsulated Monte Carlo (SEMC) method, this method introduces sphere-based rearrangement and minimization steps at each iteration, and its performance is shown through the exploration of potential energy landscapes of polycyclic aromatic hydrocarbon (PAH) clusters, systems of interest in combustion and astrophysics research. The SEMC method provides clusters that are accurate to 5% mean difference of the minimum energy at a 10-fold speed up compared to previous work using advanced molecular dynamics simulations. Importantly, the SEMC method captures key structural characteristics and molecular size partitioning trends as measured by the molecular radial distances and coordination numbers. The advantages of the SEMC method are further highlighted in its application to previously unstudied heterogeneous PAH clusters

Synthesis, Structures, and Electronic Properties of O- and S-Heterocyclic Carbene Complexes of Iridium, Copper, Silver, and Gold

O- and S-heterocyclic carbenes (OHCs, SHCs) are shown experimentally and computationally to be stronger pi acceptors than NHCs and lack, of course, substituents at the heteroatoms. These different electronic and steric characteristics make OHCs and SHCs interesting ligands for coordination chemistry. Convenient synthetic routes are presented to access their iridium(I), iridium(III), and coinage-metal(I) (Cu, Ag, Au) complexes in good yields by means of dissociation of olefins, deprotonation of precursor salts, and transmetalation from a silver carbene complex Molecular structures and detailed bonding analyses of these complexes are presented.Peer reviewe

Biology Seminar held at Des Moines, IA, January 10, 1950, Vol. 1, no.1

Seminar reporting on animal and bird populations in Iowa. Held in Des Moines, Iowa

Iowa Aviation System Plan 2010-2030: Individual Airport Report; Ida Grove Municipal Airport, June 8, 2011

The Iowa Aviation System Plan Individual Airport Report provides an overview of the aviation system in Iowa, as well as specific information related to the local Airport. Iowa’s air transportation system plays a critical role in the economic development of the state and quality of life for Iowans. The Iowa Aviation System Plan evaluates existing conditions and makes recommendations for future development of the air transportation system to meet the needs of users over the next 20 years. Airport sponsors and airport management can use the Individual Airport Report to better understand the role their airport plays in the state and use it as a guide to improve facilities and services for their aviation users

執筆者紹介・専修大学法学会評議員・奥付

This file includes 932 DICOM files of a male and female Hemiscyllium trispeculare specimen housed in the spirit collection of Naturalis Biodiversity Center, Leiden, the Netherlands with registrationnumber RMNH.PISC.35295.a and RMNH.PISC.35295.b respectively. The specimens are scanned in a medical CT scanner (Toshiba Aquilion 64) at the Leiden University Medical Center, the Netherlands at 100 kV and 150 mAs with a slice thickness of 0.5 mm

Iowa Aviation System Plan 2010-2030: Individual Airport Report; Tipton Municipal - Mathews Memorial Airport, June 8, 2011

The Iowa Aviation System Plan Individual Airport Report provides an overview of the aviation system in Iowa, as well as specific information related to the local Airport. Iowa’s air transportation system plays a critical role in the economic development of the state and quality of life for Iowans. The Iowa Aviation System Plan evaluates existing conditions and makes recommendations for future development of the air transportation system to meet the needs of users over the next 20 years. Airport sponsors and airport management can use the Individual Airport Report to better understand the role their airport plays in the state and use it as a guide to improve facilities and services for their aviation users

Optical band gap of cross-linked, curved, and radical polyaromatic hydrocarbons.

In this work, the optical band gaps of polycyclic aromatic hydrocarbons (PAHs) crosslinked via an aliphatic bond, curved via pentagon integration and with radical character were computed using density functional theory. A variety of different functionals were benchmarked against optical band gaps (OBGs) measured by ultraviolet-visible spectroscopy with HSE06 being most accurate with a percentage error of 6% for a moderate basis set. Pericondensed aromatics with different symmetries were calculated with this improved functional providing new scaling relationships for the OBG versus size. Further calculations showed crosslinks cause a small decrease in the OBG of the monomers which saturates after 3-4 crosslinks. Curvature in PAHs was shown to increase the optical band gap due to the resulting change in hybridisation of the system, but this increase saturated at larger sizes. The increase in OBG between a flat PAH and a strained curved one was shown to be equivalent to a difference of several rings in size for pericondensed aromatic systems. The effect of σ-radicals on the optical band gap was also shown to be negligible, however, π-radicals were found to decrease the band gap by ∼0.5 eV. These findings have applications in understanding the molecular species involved in soot formation

Preferences of U.S. Faculty Members regarding the Teaching- Research Nexus

The purpose of this article is to examine research and teaching trends over the past 30 years in U.S. higher education. While some faculty lean toward teaching and others toward research, often the two areas of intersect in synergistic and complementary ways. The merit of this study is that it is a follow-up of two earlier surveys. Findings include an examination of national data from 1992, 2007, and 2018 on a few select areas of the teaching-research nexus. The 2018 data includes 1,135 faculty responses from 80 higher education institutions in the United States. The once dominant research output gap between U.S. faculty and those in other countries is leveling off in many subject areas, most notably in STEM subject areas. Findings provide an in-depth analysis by faculty rank, highlighting current research and teaching preferences of junior and senior faculty members. The article also provides a model to partially explain faculty productivity among sampled participants where research preference, collaboration, and institutional research expectations serve as key predictors. Several suggestions for future areas of research are given in the conclusion section