Advancing magnetic resonance measurements of mass transport

这项拟议的研究旨在改进材料科学中使用的磁共振成像(MRI)方法。*核磁共振是一项令人惊讶的成功临床技术，因为它不会对患者造成伤害(非侵入性)，而且它可以可视化不透明物体的内部。这些同样的优势使核磁共振成为材料研究的有用技术。磁共振成像是一种非常灵活的测量方法，可以用来绘制包括温度、pH或化学势在内的各种材料属性的三维地图。我们正在开发新的方法来绘制气体和液体样本中的运动。*我们的核磁共振技术能够测量快速、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一切应用都很重要。这项拟议研究的第一步将解决在接近音速的流动中测量速度，以提高我们对这一区域中气体的理解。新的测量现在才有可能使用硬件和我们早期工作中开发的校准技术的组合。*我们还在改进磁共振成像方法，用于气体和液体的混合物，如泡沫，这在包括水修复和食品加工在内的各种应用中是至关重要的。拟议研究的第二部分是开发独立测量泡沫中的气体和液体速度，使用一种新的磁体设计，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)。*通过使用和改进我们在UNB MRI中心开发的材料MRI技术，将拟议研究的两个方面联系在一起，该技术使用短而恒定的时间对MRI信号进行编码，并形成射频激励脉冲，以选择适当的流动液体部分进行测量。

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.