AIChE Virtual Communities of Practice – Supporting Faculty during the COVID-19 Pandemic

In response to the COVID-19 pandemic, chemical engineering departments from around the world shifted their course offerings from in-person to online almost instantaneously. The AIChE Education Division immediately responded to this educational shift by developing five Virtual Communities of Practice (VCPs) that allowed faculty to share experiences and best practices as well as provide a network for emotional support. Community creation, methods and materials shared, and surveys related to the impact of this initiative will be discussed

Experiments for a Computing Class

The Course Description for Numerical Computing for Chemical Engineers Course at Missouri University of Science and Technology States that Students Will Add to their Programming Skills by Exploring Numerical Computational Techniques for … Chemical Engineering Processes. the Challenge is that the Course is Taught Early in the Curriculum Before the Students Know What Those Chemical Engineering Processes Are. the Course Has Been Structured as a Flipped Class with Class Time Devoted to Solving Problems with the Numerical Tools. to Provide Relevance for the Material, an Experimental Component Has Been Added to the Course. in the Laboratory Sessions, the Students Conduct a Brief Experiment or Activity and Then Analyze that Process using the Computational Technique for the Week. the Activities and Experiments Take No More Than 10 Minutes to Conduct and Use Inexpensive Materials. in This Paper, the Author Will Present How the Course Was Flipped to Accommodate the Lab Sessions, Describe the Experiments Used in the Course, and Relay the Student Response to This Course

Generalizing Boolean Satisfiability II: Theory

This is the second of three planned papers describing ZAP, a satisfiability engine that substantially generalizes existing tools while retaining the performance characteristics of modern high performance solvers. The fundamental idea underlying ZAP is that many problems passed to such engines contain rich internal structure that is obscured by the Boolean representation used; our goal is to define a representation in which this structure is apparent and can easily be exploited to improve computational performance. This paper presents the theoretical basis for the ideas underlying ZAP, arguing that existing ideas in this area exploit a single, recurring structure in that multiple database axioms can be obtained by operating on a single axiom using a subgroup of the group of permutations on the literals in the problem. We argue that the group structure precisely captures the general structure at which earlier approaches hinted, and give numerous examples of its use. We go on to extend the Davis-Putnam-Logemann-Loveland inference procedure to this broader setting, and show that earlier computational improvements are either subsumed or left intact by the new method. The third paper in this series discusses ZAPs implementation and presents experimental performance results

Generalizing Boolean Satisfiability III: Implementation

This is the third of three papers describing ZAP, a satisfiability engine that substantially generalizes existing tools while retaining the performance characteristics of modern high-performance solvers. The fundamental idea underlying ZAP is that many problems passed to such engines contain rich internal structure that is obscured by the Boolean representation used; our goal has been to define a representation in which this structure is apparent and can be exploited to improve computational performance. The first paper surveyed existing work that (knowingly or not) exploited problem structure to improve the performance of satisfiability engines, and the second paper showed that this structure could be understood in terms of groups of permutations acting on individual clauses in any particular Boolean theory. We conclude the series by discussing the techniques needed to implement our ideas, and by reporting on their performance on a variety of problem instances

The hydrodynamics of swimming microorganisms

Cell motility in viscous fluids is ubiquitous and affects many biological processes, including reproduction, infection, and the marine life ecosystem. Here we review the biophysical and mechanical principles of locomotion at the small scales relevant to cell swimming (tens of microns and below). The focus is on the fundamental flow physics phenomena occurring in this inertia-less realm, and the emphasis is on the simple physical picture. We review the basic properties of flows at low Reynolds number, paying special attention to aspects most relevant for swimming, such as resistance matrices for solid bodies, flow singularities, and kinematic requirements for net translation. Then we review classical theoretical work on cell motility: early calculations of the speed of a swimmer with prescribed stroke, and the application of resistive-force theory and slender-body theory to flagellar locomotion. After reviewing the physical means by which flagella are actuated, we outline areas of active research, including hydrodynamic interactions, biological locomotion in complex fluids, the design of small-scale artificial swimmers, and the optimization of locomotion strategies.Comment: Review articl

Fast Monte Carlo Algorithms for Permutation Groups

AbstractWe introduce new, elementary Monte Carlo methods to speed up and greatly simplify the manipulation of permutation groups (given by a list of generators). The methods are of a combinatorial character, using only elementary group theory. The key idea is that under certain conditions, "random subproducts" of the generators successfully emulate truly random elements of a group. We achieve a nearly optimal O(n3 logcn) asymptotic running time for membership testing, where n is the size of the permutation domain. This is an improvement of two orders of magnitude compared to known elementary algorithms and one order of magnitude compared to algorithms which depend on heavy use of group theory. An even greater asymptotic speedup is achieved for normal closures, a key ingredient in group-theoretic computation, now constructible in Monte Carlo time O(n2 logcn), i.e., essentially linear time (as a function of the input length). Some of the new techniques are sufficiently general to allow polynomial-time implementations in the very general model of "black box groups" (group operations are performed by an oracle). In particular, the normal closure algorithm has a number of applications to matrix-group computation. It should be stressed that our randomized algorithms are not heuristic: the probability of error is guaranteed not to exceed a bound ϵ > 0, prescribed by the user. The cost of this requirement is a factor of |log ϵ| in the running time

Multiphase Equilibrium Behavior of the Mixture Carbon Dioxide + Ethane + Methanol

The Three-Phase Liquid-Liquid-Vapor (Llg) Phase Equilibrium Behavior of the Mixture Carbon Dioxide + Ethane + Methanol Was Experimentally Studied. the Boundaries of the Three-Phase Llg Region in Pressure-Temperature Space Are Delineated. Compositions and Molar Volumes of the Two Liquid Phases and the Vapor Phase Along the 288.15 and 298.15 K Isotherms Are Reported. © 1994, American Chemical Society. All Rights Reserved

A Survey of Women in Academia and the role of a Multidisciplinary Professional Society

The Society of Women Engineers (SWE) is a global professional society of over 30,000 members with a mission to “Stimulate women to achieve full potential in careers as engineers and leaders, expand the image of the engineering profession as a positive force in improving the quality of life, and demonstrate the value of diversity”1. SWE is an organization that is deeply rooted in industry. The founding members were employed by firms that are a result of the industrial revolution, and thus the focus of its membership is on those that work for industry, consultants, and often themselves. This focus has unintentionally left a large population of its membership, the academic population, underrepresented and misunderstood. Early discussion at the board level in the mid 2000’s indicated a willingness for a paradigm shift. However, the representation of academics on the board and other leadership roles has been lacking. This can be attributed to the lower numbers of this group relative to the whole, as well as the requirements of tenure that do not support the time and dedication to such an endeavor. A small but influential group of members, including a former board member, and a few involved at various levels of the society have been working toward increasing opportunities for women in academia (WIA). Some of the initiatives have been the societal support of the WIA committee, the addition of professional development opportunities targeting women in academic careers, providing recognition and awards, and aiding in networking opportunities. These all lead toward career advancement, making SWE more attractive to women engineers in the academe. To further our understanding of available opportunities and those opportunities that will make membership and active participation more attractive to members in academia, a survey was developed. Information gathered by the survey include demographics, perceived needs, and potential contributions the individual could make in furthering the creation of professional development opportunities for this population. This work is intended to share the results of this survey, using descriptive statistics, further developing our understanding of this underserved population within SWE

Effects on the maternofetal unit of the rabbit model after substitution of the amniotic fluid with perfluorocarbons

Objectives: Exchanging amniotic fluid (AF) with perfluorocarbon (PFC) may serve as a medium for fetoscopic surgery. This study evaluates the distribution and physiologic effects of intraamniotic PFC as a medium for fetoscopy. Methods: Fetuses of 17 pregnant rabbits underwent either exchange of the AF with PFC, electrolyte solution (ES), or control. The quality of vision during fetoscopy was assessed in AF and PFC. After 6 h, we determined the distribution of PFC in the maternofetal unit. Results: Quality of vision during fetoscopy was better in PFC than with AF. There was no difference in fetal survival between the study groups. PFC was demonstrated on X-ray in the pharynx of 4 fetuses, and the esophagus in 1. Conclusions: PFC provided an ideal medium for fetoscopy without fetal compromise. Copyright (c) 2005 S. Karger AG, Basel

Quantum levitation by left-handed metamaterials

Left-handed metamaterials make perfect lenses that image classical electromagnetic fields with significantly higher resolution than the diffraction limit. Here we consider the quantum physics of such devices. We show that the Casimir force of two conducting plates may turn from attraction to repulsion if a perfect lens is sandwiched between them. For optical left-handed metamaterials this repulsive force of the quantum vacuum may levitate ultra-thin mirrors