Portland State Magazine, Spring 2021

ANDREW WOLLMAN MS ’12 PHD ’16 PIECES OF HISTORY ’s s barometer 19 Defying Gravity In the center atrium of Portland State’s Engineering Build- ing sits the Dryden Drop Tower (see photo, left), a six-story marvel that defes gravity—literally. Objects dropped from it experience a 100-foot fall and 2.1 seconds of weightless- ness, allowing students and researchers to test how materials and prototypes would behave in space. While the atrium of the Engineering Building was originally designed with room for the tower, actual construc- tion was only a pipe dream.Te drop tower didn’t become a reality until 2010, when donors gave money in honor of Robert Dryden, who served as dean of the Maseeh College of Engineering and Computer Science for 13 years until 2008. “It’s the frst of its kind,” says Mark Weislogel, mechanical engineering faculty, who previously worked at NASA. “It’s a high-rate drop tower that’s extremely safe, that’s in an open- air environment and which has a very low cost to operate.” Te low-cost design makes doing experiments more acces- sible. “Students come out of here with hundreds and hundreds of ‘drops,’ more than most NASA folks,” says Weislogel. As a result, they develop a feel for how things behave in low gravity. PSU drop tower alumni use this intuition as aerospace engineers at companies like Blue Origin, and their drop tower experiments have sparked publications in scientifc journals, multiple patents and even a start-up company. Weislogel and his lab use the drop tower to test 3D-printed prototypes for fuid systems to be used in spacecraft. Successful ideas are tested on the International Space Station (ISS), with the lab running experiments with astronauts via the NASA-PSU telescience center—a remote control room for communicating with the ISS. One notable discovery: the Space Cup, which astronauts on the ISS now sip from to enjoy their morning brew. —SUMMER ALLEN World’s Tallest 20 Barometer In 2013, Portland State took its commitment to recycling to new heights by transforming recycled drainpipes into the world tallest barometer (see photo, right). Barometers measure atmo- spheric pressure.Te taller they are, the easier it is to measure small diferences in pressure. PSU’s is a whopping 47 feet tall, earning it a place in fuids textbooks. Besides its height, the PSU barometer is unique because it uses vacuum pump oil rather than mercury or water as its barometric fuid. A good barometric fuid must have very low vapor pressure.Te oil used in PSU’ has a vapor pressure four orders of magnitude less than mercury. Development engineer Tom Bennett, who conceived and led the project to install the barometer in the Engineering Building, got the idea after plumbers salvaged a trove of old glass drainpipes removed during the remodel of Science Building 2. Seventeen students, faculty and staf helped design and install the barometer. Now civil engineer- ing students have the special opportunity to use the barometer in their fuids lab course. When students are allowed back on campus, Bennett has another project for them: replacing the 40-year-old glass pipe fttings with new coupling to reduce air infltration.Tis means rebuilding the barometer, all 47 feet of it. A tall order, indeed. —SUMMER ALLEN