Profile page for: Igor Mastikhin | UNB

Igor Mastikhin

Professor

PhD

Physics

I.U.C. Physics/Admin 213

Fredericton

mast@unb.ca
1 506 458 7927



I apply Magnetic Resonance methods to studies of materials and processes with short signal lifetimes. I am interested in two areas of NMR and MRI applied to materials science: two-phase media and portable NMR instrumentation/applications.

  1. Two-phase media (microbubbles, microdroplets) and how to measure them quantitatively with MRI: MRI can be sensitive to a wide variety of physical and chemical parameters. Both a spatially resolved mapping of the medium (if you do MRI, preferably a single-point based one) and a fast bulk measurements can be performed. Our MRI studies of spray show that you can investigate very fast flows both inside a spray nozzle (where optical methods are inapplicable due to the lack of transparency) and in the atomization region noninvasively and quantitatively.

    In addition to that, we just started a research in MRI of freezing sprays. When droplets of water become supercooled, a so-called “freezing rain” takes place, covering any cold surface with a layer of ice. This is a common winter phenomenon in Atlantic Canada and in other regions with frigid winter temperatures. Its close relative is a freezing sea spray where wind-blown droplets of seawater accumulate on vessels, lighthouses, any maritime structures. Ice has very short NMR signal lifetimes and thus is very hard to detect by conventional NMR instruments. However, there is a considerable amount of unfrozen concentrated saline solution – brine – inside the ice. We attempt to gain more information about the ice microstructure and formation dynamics by measuring NMR signal from the brine.

  2. My other research interests are in the development of portable, unilateral NMR instruments with controlled parameters (sensitive volume size and location, magnetic field gradient) (in collaboration with Drs. B.J.Balcom and B.Colpitts), and how to use them to measure various interesting and useful things. Over several years, our then graduate student A.Marble has been very successful in this development that resulted in several research papers and patents; he was the recipient of the 2007 NSERC Innovation Challenge Award and the 2008 NSERC Doctoral Prize.

Recently, we decided to use portable NMR to measure small-amplitude vibrations of the medium. In MR elastography, NMR signal is sensitized to vibrations by synchronizing the vibrations with the oscillating magnetic field gradients. In the most basic portable NMR, magnetic field gradients are permanent: you just do measurements in the presence of a stray field of an array of permanent magnets, so you don't really have control over the gradients per se. You can, however, control the spin phase by flipping it with RF pulses, so we generated an "effective" square-wave gradient, a la Stepisnik-Callaghan, by using the CPMG 180-pulse train. The resulting sensitivity to ~100-nm amplitude vibrations can be improved further and, unlike the conventional MR elastography where you need a big MRI scanner, the NMR sensor can fit into your palm.

Selected publications

Grant Wilbur, Bryce MacMillan, Kyle M. Bade, Igor Mastikhin. “MRI monitoring of sea spray freezing”, Journal of Magnetic Resonance (2020) 310, 106647.

Adair, A., Mastikhin, I.V., Newling, B."Motion-Sensitized SPRITE Measurements of Hydrodynamic Cavitation in Fast Pipe Flow", Magnetic Resonance Imaging (2018) 49, 71-77.

I.V.Mastikhin, K.Bade, S.Ahmadi, K.Bade, A rapid magnetization preparation for MRI measurements of sprays, J. MAGN RESON (2017) 283, 52-60

I.V.Mastikhin, A.Arbabi, K.Bade, Magnetic Resonance Imaging measurements of a water spray upstream and downstream of a spray nozzle exit orifice, J.MAGN.RESON (2016) 266, 8-15