Acquisition of an Ultra-High Temperature Acoustic Interferometer

9903070 lange这笔拨款为密歇根大学高压和温度实验室购买超声波干涉仪提供部分费用支持。该仪器将用于测量多组分硅酸盐液体的可压缩性。该设备的超高温能力（2000摄氏度）将允许访问广泛的熔体成分，包括那些具有高液相温度的（例如过铝液体，熔融橄榄岩）和那些过于粘稠而无法在1600摄氏度以下获得轻松声速的（例如熔融流纹岩）。通过测量跨越几百度的温度区间的松弛声速，对熔体可压缩性的温度依赖性的限制将大大改善。干涉仪还将在较低温度下用于含挥发性液体（含氟和磷）和各种碳酸盐岩液体，在确定不发生挥发性损失的条件下。另一个应用是检查在一bar条件下硅酸盐熔体的可压缩性变化，这些变化是由组成引起的阳离子（Al3+， Fe3+和Ti4+）的配位变化。这些实验将为理解压力引起的这些阳离子配位变化对熔体密度的影响提供类比。除了私家侦探丽贝卡·兰格（Rebecca Lange）之外，密歇根大学其他可能在研究中使用该设备的教员包括副教授张友学和Lars Stixrude。这将是第一个能够在液体上进行超高温工作的声学干涉仪，因此可能会吸引整个美国的外部用户

9903070LangeThis grant provides partial support of the costs to acquire an ultrasonic acoustic interferometer for the High Pressure and Temperature Laboratory at the University of Michigan. This instrument will be used to measure the compressibilities of multicomponent silicate liquids. The ultra-high temperature capability of the apparatus ( 2000 degrees centigrade) will allow access to a wide range of melt compositions, including those with high liquidus temperatures (e.g. peraluminous liquids, molten peridotite) and those that are too viscous to obtain relaxed sound speeds below 1600 degrees centigrade (e.g. molten rhyolite). Constraints on the temperature dependence of melt compressibility will be substantially improved by measuring relaxed sound speeds over temperature intervals spanning several hundered degrees. The interferometer will also be used at lower temperatures on volatile-bearing liquids (containing fluorine and phosphorous) and a variety of carbonatite liquids under conditions where it is established that volatile loss does not occur. An additional application is to examine variations in the compressibility of silicate melts undergoing composition-induced coordination change of cations (Al3+, Fe3+, and Ti4+) at one bar. These experiments will provide analogies for understanding the consequences of pressure-induced coordination change of these cations on melt density. In addition to the P.I., Rebecca Lange, other faculty at the University of Michigan who are likely to utilize the equipment in their research include Associate Professors Youxue Zhang and Lars Stixrude. This will be the first acoustic interferometer that is capable of ultra-high temperature work on liquids and is thus likely to attract outside users throughout the U.S.***