Advancing magnetic resonance measurements of mass transport

这项研究旨在改进磁共振成像（MRI）方法，以用于材料科学。**MRI是一种非常成功的临床技术，因为它不会对患者造成伤害（非侵入性），并且可以可视化不透明物体的内部。这些相同的优点使MRI成为研究材料的有用技术。MRI是一种非常灵活的测量方法，可用于绘制各种材料特性，包括三维温度、pH值或化学势。我们正在开发新的方法来映射气体和液体样品中的运动。** 我们的MRI技术能够测量快速湍流气流中的速度和速度波动，这对于它们在从风力涡轮机到喷气发动机的各种应用中的重要性。这项研究的第一部分将解决接近声速的流动速度的测量，以提高我们对这种情况下气体的理解。新的测量现在才可能使用我们早期工作中开发的硬件和校准技术的组合。** 我们还在改进用于气体和液体混合物（如泡沫）的MRI方法，这在水处理和食品加工等各种应用中至关重要。拟议研究的第二部分是使用新的磁体设计开发泡沫中气体和液体速度的独立测量，该磁体设计允许在水平和垂直之间的任何方向上测量泡沫（和其他多相流）。** 拟议研究的两条线通过使用和改进我们在UNB MRI中心开发的材料MRI技术连接起来，该技术使用短而恒定的时间来编码MRI信号和射频激励的成形脉冲，以选择流动流体的适当部分进行测量。

The proposed research aims to improve magnetic resonance imaging (MRI) methods for use in materials science. ******MRI has been an astonishingly successful clinical technique because it causes no harm to the patient (is non-invasive) and because it can visualise the inside of opaque objects. These same advantages make MRI a useful technique for the study of materials. MRI is a very flexible measurement method, which can be used to map a variety of material properties including temperature, pH or chemical potential in three dimensions. We are developing new methods to map motion in gas and liquid samples. ******Our MRI techniques are able to measure velocity and the fluctuations of velocity in fast, turbulent gas flows, which are important for their application in everything from wind turbines to jet engines. The first strand of this proposed research will address the measurement of velocity in flows approaching the speed of sound to improve our understanding of gases in this regime. The new measurements are only now possible using a combination of hardware and calibration techniques developed in our earlier work. ******We are also improving MRI methods for use in mixtures of gases and liquids, such as foams, which are critical in a variety of applications including water remediation and food processing. The second strand of the proposed research is the development of independent measurements of the gas and liquid velocities in foams, using a new magnet design, which allows the foams (and other multi-phase flows) to be measured at any orientation between horizontal and vertical. ******The two strands of the proposed research are connected by the use and improvement of materials MRI techniques we have developed at the UNB MRI Centre, which use short, constant times to encode the MRI signal and shaped pulses of radiofrequency excitation to select the appropriate section of the flowing fluids for measurement.