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Chemistry

Research

Solid Oxide Fuel Cells (SOFC): Materials and Design
Electronic Microscope Image - edge on
We are working in an industry-academic research consortium dedicated to developing an SOFC power plant for mobile applications.  The SOFC has found many applications in stationary power plant solutions but when the same technology migrates to a mobile platform, several new issues arise and are at the heart of what we are investigating: (a) Start-up time. The high temperature (1000 K) operation, ceramic brittleness, and numerous interfaces with thermal expansion differentials have called for slow start-up times, which must be reduced for mobile applications. (b) Dynamic load response. In stationary applications, SOFCs are powered to produce stable base load energy needs.
 
A mobile application, however, experiences constant changing power demands – acceleration, braking, idling in traffic, cruising at highway speeds, etc. – and this requires a cell stack design that is able to respond to this changing demand. (c) Volume commensurate with application.  While stationary applications can be quite large, our solution needs to be scaled in size to appropriately power a car without occupying more space than is normally found in the engine compartment.  We are tackling these challenges through a combination of novel material choices and advanced thin film deposition techniques, including pulse laser deposition (PLD) and atomic layer deposition (ALD).  We are forming dense, extremely thin films and testing them for their applicability in this application.
Nickel Carbonyl Refining
Metalic nickel produced by the process
We are working with a global industrial partner to explore chemical details surrounding the refining of Ni ore use the Ni(CO)4 or Mond, process.  To date, we have focussed on understanding the NiO reduction step in the refining process.  Following extraction, various mechanical operations on the ore, and an oxidative roasting, the NiO powder is reduced to the impure Ni powder that is refined using the carbonyl Mond process.  The reduction step has had several puzzling aspects to it, including the effect of some additives, the presence of different impurities, and the chemical mechanism at the heart of the process.  We have resolved a number of issues and are making recommendations to the company regarding future ore processing procedures.

Studying the Grading Effectiveness of Large Groups of Graders
Picture of someone grading an exam
In large classes (we have upwards of 2000 students in our first-year chemistry courses), exams must either be entirely multiple choice in format or large groups of graders, drawn from the Teaching Assistant pool, must be assembled to grade these en masse.  The challenge is to ensure the accuracy and fairness of the grading across the entire class.  We have been developing new statistical measures with which to compare the variance of grading that is found in an effort to measure the effectiveness of tools used to train graders and ensure the success of the grading process.  We have been applying this to our first year grading process and have so far identified the range of correlation anticipated and how certain training activities may have an impact.  Work in this area is ongoing.
Conceptual Learning Tendencies and Student Performance
A plot showing a data set with a linear regression
We have worked with some American colleagues to find ways to determine student’s approach to learning and how this may effect their scholastic performance.  A psychometric instrument developed at the University of Washington in St. Louis is proving successful at identifying students who rely on rote learning techniques as compared to those who have a more theory-based approach: this is able to classify students who extend their learning into new situations compared to those who are only able to solve problems exactly like ones they have solved previously.  We have categorized the students in our first year classes here at Guelph using this instrument and have compared their performance based upon their learning approach.  The hope is to identify students with exemplar (rote) learning tendencies and develop interventions to help them become more expert learners
Psychometrics and the Learning of Chemistry
Marking a bubble sheet test
One of the challenges that physical scientists have in undertaking serious educational research lies in recognizing that while chemistry is a physical science, the learning of chemistry is a social science.  The study of that learning requires scientific approaches that are different than what we are used to employing.  We must use a much deeper understanding of statistical methods than is commonly done.  We have developed computer codes the apply Item Response Theory (IRT) and Classical Test Theory (CTT) to the exams undertaken by students in our first year chemistry classes, based on Joint Maximum Likehood Estimations and Marginal Maximum Likelihood Estimations.  We are also working to develop a Bayesian routine.  All of these can be used to characterize both student performance and exam quality.  With this we hope to get a better understanding of student performance, and things that make exam questions particularly effective in exam settings.
Effectiveness of POGIL Materials in Learning Chemistry
An image showing a scattered green dots, and a graph suggesting a distribution.
In the mid-1990’s, a group of chemists developed a new instructional approach to chemistry labelled Process Oriented Guided Inquiry Learning or POGIL.  Since then it has grown significantly to included proponents in disciplines throughout arts, science, and the humanities.  The word “Inquiry” indicates that the learning is accomplished by having students ask and solve questions, rather than just laying out the learning information for them.  The “Guided” aspect is in opposition to “Open Inquiry”; the materials carefully guide the students rather than just “throwing them into the deep end”.  It seeks to guide students to the needed information, while still preserving their inquiring engagement.  “Process Oriented” implies that a major goal of the activity is helping students to develop the skill of learning - the process of knowledge acquisition, evaluation, and implementation.  I have been working to implement or develop POGIL materials for both chemistry and nanoscience and I have come to several conclusions: 
(1) student engagement is grounded in questions, not answers,
(2) POGIL materials need to consist mostly of questions, not statements,
(3) students need to have a tool with which they can interact to learn the relevant information,
(4) since students are more likely to challenge the statement of a peer than that of an instructor, they are more intellectually engaged in peer-to-peer learning as they are questioning the discussion, rather than just absorbing it, and
(5) students learn chemistry better within the context of relevant issues, rather than simply the chemistry itself. 
I am developing new learning resources along these lines and will test them in the classroom in the future.  I will arrange this so as to demonstrate the effectiveness of these tools compared to traditional POGIL materials (this is largely found in items 3 and 5 above) and as compared to the more standard lecture environment (which is different according to all 5 items above).
Evaluating Students' Scale Literacy
Ball and stick models of three molecules
Which is bigger? A horse or an elephant? Most of us would easily answer this question because we have in some measure experienced them often.  How many gold atoms are found in a spherical Au nanoparticle with a radius of 1 nm?  This is harder for most of us; usually we guess to low (about 60 atoms).  Or how about time?  How many weeks until Christmas?  Most of us would get it fairly close rather quickly.  If you are very healthy, you might live to be a hundred – a centenarian.  How many of your lifetimes has it been since the dinosaurs disappeared from the earth?  (About 660,000 lifetimes.)  Again, this would be much more of guess for most people.  Understanding scientific processes and concepts across many order of magnitude of scale – size, time, quantity, etc. – is a core skill but is difficult for most people when it requires understanding that is more than three orders of magnitude away from their everyday experience, unless they have intentionally developed a more thorough understanding.  We have developed an on-line tool designed to assess a student’s understanding of scale to smaller dimensions (cells and atoms).  We are attempting to understand if, when and where in their scientific education they develop an appropriate sense of scale and how that may be different between disciplines and academic experience.  We further want to quantify how this skill may impact their success in their academic program.