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The fate of organic contaminants in soils and sediments is influenced by sorption of the compounds to surfaces of soil materials. We investigated the interaction among sorption of an organic compound, cation exchange reactions, and both the size and swelling of smectite quasicrystals. Two reference smectites that vary in location and amount of layer charge, SPV (a Wyoming bentonite) and SAz-1 were initially Ca- and K-saturated and then equilibrated with mixed 0.01 M KCl and 0.005 M CaCl2 salt solutions both with and without the presence of 200 mg L(-1) m-dinitrobenzene (m-DNB). In general, sorption of m-DNB increased with the amount of K+ in the system for both clays, and the SPV sorbed more m-DNB than the SAz-1. Sorption of m-DNB increased the preference of Ca-SPV for K+ relative to Ca2+ but had little effect on K+-Ca2+ selectivity for K-SPV. Selectivity for K+ relative to Ca2+ was slightly higher for both K-SAz-1 and Ca-SAz-1 in the presence of m-DNB than in its absence. Distinct hysteresis loops were observed for the K+-Ca2+ cation exchange reactions for both clays, and the legacy of having been initially Ca- or K-saturated influenced sorption of m-DNB by SPV but had little effect for SAz-1. Suspension X-ray diffraction was used to measure changes in d-spacing and the relative thickness of smectite quasicrystals during the cation exchange and m-DNB sorption reactions. The results suggest that interactions among cation exchange and organic sorption reactions are controlled byan inherently hysteretic complex feedback process that is regulated by changes in the size and extent of swelling of smectite quasicrystals.

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Innovation is at its best when we are thrusted into an emergency situation that tests protocols and established norms. In this chapter, authors reflect on the journey of a team of instructional designers in an online learning design unit of a large mid-western university amidst COVID-19. With the influx of a multitude of courses to be transitioned to the online platform, authors describe challenges faced by their unit, coping mechanisms, and lessons learned during this phase. They describe inclusive design thinking and uninterrupted practice in return to robust instructional design models, such as Understanding by Design and Universal Design for Learning. The chapter concludes with examples of tried and tested internal tools and an adaptive workflow catering to a shortened development timeline. These practices and reflections serve as a guiding light as the global world navigates online learning to meet increasing demands of new-age digital accessibility and online course design considerations in higher education beyond COVID-19.

dia and subsequently received her MS in Environmental Chemistry from Iowa State University. She received her second MS in Education with specialization in Curriculum and Instructional Technology and her Instructional Design certificate from Iowa State University in 2015. As an instructional designer, she assists faculty in the College of Engineering and Liberal Arts and Sciences, to design and develop asynchronous online and blended courses, providing technical, pedagogical support and instructional support. She has supported over 25 faculty members successfully transition to the online learning environment and has supported over 50 online courses.Prof. Ahmed E. Kamal, Iowa State University Ahmed E. Kamal received a B.Sc. (distinction with honors) and an M.Sc. both from Cairo University, Egypt, and an M.A.Sc. and a Ph.D. both from the University of Toronto, Canada, all in Electrical Engineering in 1978, 1980, 1982 and 1986 This exploratory essay describes the design and implementation of alternate assessment techniques, such as asynchronous online discussions, virtual labs, open ended module assignments and final project, in an asynchronous online computer engineering graduate course on cognitive radio networks. The course is designed based on the premise of formative evaluations, that is, incorporating a feedback mechanism for each assessment submission. Such feedback provides means for both the instructors and learners to engage with the content and with each other in a meaningful way to create an enriching learning experience. Moreover, designing assessments that stretches students' thought-process is critical to engineering pedagogy. This is implemented in the course as structured threaded discussion forums, governed by instructors that provide thought-provoking guiding questions followed by peer discussion. This essay also explores the design and implementation of virtual laboratory sessions complementing the bi-weekly homework assignments and a final project. It describes the assessment design decisions, based on the overall course learning outcomes, taken to suit the online learners. The aim of this essay is to inform, the community of asynchronous online computer engineering educators, of assessment techniques, other than the traditional formats of multiple choice questions and sit-in proctored exams, based on this cognitive radio networks class. It will also showcase the ways to implement such assessments successfully in an online environment along with the highlighting the overall design process of the course.