Experts and a gizmo help avert LRT surprises

Posted on Tuesday, May 24, 2016

A device made from a hula hoop and piping, affixed to a trolley cart.

Sean Kirkwood created a magnetometer to measure magnetic fields around campus, including on the nearby Transitway.

By Brandon Gillet

Experts at uOttawa are taking steps to ensure that the forthcoming light rail transit (LRT) trains do not disturb sensitive research equipment on campus.

The Office of Risk Management and Facilities staff have teamed up to conduct a baseline study measuring vibrations, magnetic fields and electric fields around campus that, if increased, could have adverse effects on research.

“When the LRT system comes in and runs alongside the campus, it’s going to vibrate the area, emit magnetic fields, and probably electric fields, because of the nature of the technology,” said risk management specialist Sean Kirkwood.

Kirkwood took measurements in December using a magnetometer that he fashioned out of his child’s hula hoop and 150 metres of TV wire, all wrapped in aluminum foil, creating a stand out of pipe and hooking the whole gizmo to a trolley cart, a computer and an independent power source.

Sean Kirkwood

The Office of Risk Management’s Sean Kirkwood. Photo: David Taylor Photo Studio

“I walked around campus with it and chose specific areas containing things like pipes, which can amplify magnetic or electric fields,” says Kirkwood, who has a PhD in electrical engineering.

The data was then used to guide an external contractor, who did their own measurements in April. Another contractor used accelerometers to measure vibrations in computer labs. These included the lab in the basement of the SITE building, where users have reported being slightly disturbed by OC Transpo buses.

However, the main focus of concern after the LRT comes online is sensitive research equipment such as the Nuclear Magnetic Resonance (NMR) Facility and the atomic microscope in Colonel By Hall.

Glenn Facey, manager of the NMR Facility, explained that even small changes in electromagnetic fields can cause serious problems in NMR spectrometers.

Samples of organic compounds mixed in a solvent are placed in the spectrometer, which has a super-conducting magnet 100,000 times more powerful than the Earth’s magnetic field. The samples are hit with radio waves calibrated to read the frequency of an atom within a molecule. The results show peaks on a readout similar to an EKG, which indicate the presence of a particular element.

“If there is an LRT that adds to the magnetic field, even a small amount, it will shift these peaks and skew our data,” said Facey, who has a PhD in chemistry.

There are three spectrometers in MacDonald Hall and one in Marion, which are both close to the Transitway and extremely sensitive to variations in magnetic field.

Glenn Facey, debout, pose les mains sur le grand réservoir d’un spectromètre.

Glenn Facey with an NMR spectrometer.

“Walking by the (spectrometer) magnet with my keys on my belt while data is being collected would be enough to shift the peaks,” Facey said. “It’s the difference between doing a productive experiment and not doing one at all.”

The city will now run simulations based on the University’s list of sensitive equipment and the LRT project design. If vibration and magnetic and electric field data look likely to increase, they will suggest mitigating measures. These could include changing how electricity runs through the main cable, or using aluminum in manufacturing the LRT cars, Facey said.

“If those measures aren’t enough, the only alternative would be for us to move,” he said, adding that moving the systems in question would cost about $40,000 for each spectrometer, and require a considerable amount of space.

“We’re trying to get ahead of that, which is the risk management side,” Kirkwood said. “What’s the impact, and how do we mitigate it? We’ve got two years before this comes online, so let’s ask these questions now.”

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