TRANSPORT PROCESSES LAB

or how to measure the evaporation of a lake when a warm breeze blows

Now in its sixth year, ChemE 157, the Transport Processes Laboratory that is required of all majors, "is one of the department's best courses for undergraduates," says Professor Susan Muller, one of the instructors, along with Professor David Graves. "The students, typically juniors, do straightforward experiments in the lab with basic equipment and then perform in-depth analysis with modern computational tools. The software package that we use is very appealing because it makes it easy to visualize mass and energy transfer and helps our students strengthen their knowledge of fundamental chemical engineering principles," adds Muller.

"But what really makes the class special is that there is so much attention from the instructors," notes Muller. Instead of sitting in a lecture hall with 100 other students, the participants are divided into two-student teams that present five oral and two written reports to the instructor. "For some of the students it is the first time they have really interacted one-on-one with the faculty, and that can be a little daunting. But these presentations are excellent preparation for what they will do throughout their career, and by the end of the semester the students are much more confident," she adds.

"Another reason the class is popular," notes Brian Mayer, one of the graduate student instructors, "is that engineers like to get their hands dirty."

Henrik Wallman agrees. "By creating a course aimed at juniors, we allow them to get hands-on experience at an earlier stage," says Wallman, a lecturer and the academic coordinator for the course. "Additionally, integrating this software into the classroom is good from a pedagogical point of view. The students run the experiment and then do exactly the same thing on the computer. They are basically doing an experiment by computer. Although we give them some instructions and guidelines, it is still up to the students to figure out the final trends, quantify the data, and interpret the results."

And the students themselves like the hands-on approach. Senior Manuel Delgado models heat conduction in a brass wire, having already gathered his experimental data. He wants to learn the program to improve his job prospects. "I worked with the software outside of class in Bixby Commons to increase my proficiency. It took some time to learn how to change the conditions, parameters and equations, but now I know what is going on."

There are five different experiments, two of which are also modeled at the computer. One of the dual-purpose experiments is measuring water evaporation from a small "lake" on an enclosed scale. Wallman likes to ask his students, "Can you predict how much water evaporates from a lake when a warm breeze blows?" because, as he notes, in chemical engineering this is an everyday occurrence. What sounds impossible is actually accomplished by weighing the lake, blowing warm air and then measuring the decrease in water weight as a function of wind speed and wind temperature.

Working in a Lewis Hall classroom recently renovated with private funding, Anton Chakhmatov, a fourth-year student in chemical engineering, is busy using a capillary tube to measure the evaporation of methanol. "This class nicely complements the ChemE 150 series (a two-semester series that teaches transport and separation processes). I am looking forward to seeing how precisely the mathematical models compare to the experimental results."

"The experiments serve to solidify the fundamentals that may seem abstract in the classroom," adds Brian Mayer. "The students leave the course with a firm understanding of basic principles because they learn by doing: run experiments, use equations and get meaningful results."

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