Sustained Bio-Convection in Porous Media

提案编号：cts -0500466项目负责人：Peter vadasz附属于：北亚利桑那大学提案标题：多孔介质中的持续生物对流多孔介质中的持续生物对流该提案是由研究人员主动提交给化学和运输系统部门的，随后被转移到热传输和热加工项目，以获得后续资金。本项目是一项基础研究，旨在通过理论和实验技术研究流体饱和多孔介质（如土壤、食物、人体组织）中持续生物对流的影响。生物对流是由于流体和悬浮在流体中的可运动微生物之间的密度差异所产生的浮力而引起的重力驱动的流体运动现象。迄今为止，尽管微生物在多孔环境中自然生长，但多孔介质中生物对流的影响很少或没有得到重视；土壤、食物和人体组织就是最基本的例子。我们研究的一个主要焦点是与生物对流运动的可持续性有关。现有的纯流体和多孔介质中生物对流的研究都排除了生物对流过程中微生物的生长，因为所涉及的时间尺度很短（从几秒到5分钟）。然而，当这种对流在很长一段时间内的可持续性问题出现时，必须考虑到微生物的生长。如果多孔介质中持续的生物对流是可能的，它为研究其对土壤、食物和人体组织中微生物增殖的影响开辟了途径，这是理论结果应用的重要途径。然后，如果生物对流增强微生物增殖，在某些情况下可能是不希望的，例如在食品中，或者如果可以用于污染土壤修复的特定微生物将被生物对流过程“帮助”进入土壤中的污染区域，这可能是可取的。因此，该研究将扩展现有的关于多孔介质中生物对流的稀缺知识。这项研究的预期成果是在期刊和会议上发表，从而传播科学成果，与来自南非的两个团队进行强有力的国际合作，以及来自北亚利桑那大学的大约六名本科生将积极参与该项目。

National Science FoundationABSTRACTProposal Number: CTS-0500466Principal Investigator: Peter VadaszAffiliation: Northern Arizona University Proposal Title: Sustained Bio-Convection in Porous MediaSUSTAINED BIO-CONVECTION IN POROUS MEDIAThe proposal was received as an unsolicited investigator-initiated submission to the Chemical and Transport Systems Division and was subsequently transferred to the Thermal Transport and Thermal Processing Program for subsequent funding. This project is a fundamental research aimed at investigating the effect of sustained bio-convection in a fluid saturated porous medium (such as soil, food, human tissue) by applying theoretical as well as experimental techniques. Bio-convection is the phenomenon of gravity driven fluid motion due to buoyancy forces resulting from density differences between the fluid and motile micro-organisms suspended in the fluid. So far effects of bio-convection in porous media received little or no attention, despite the fact that micro-organisms grow naturally in porous environments; soil, food and human tissues serve as basic examples. A major focus of our research is linked to the sustainability of the bio-convection motion. The existing work on bio-convection in both pure fluids and porous media exclude micro-organism growth during the bio-convection because the time scales concerned were very short ( between a few seconds and up to 5 minutes). However, when the question of the sustainability of this convection over long times arises, micro-organism growth has to be accounted for. If sustained bio-convection in porous media is possible it opens the avenue to investigate its impact on microbial proliferation in soil, food and human tissue, an important avenue for application of the theoretical results. Then, if bio-convection enhances microbial proliferation it may be undesirable in some cases, e.g. in food, or it might be desirable if specific micro-organisms that can be used for contaminated soil remediation will be "helped" by the bio-convection process to access contaminated regions in the soil. The research will therefore expand the existing scarce knowledge on bio-convection in porous media. The anticipated outcomes from this research are publications in journals and conferences hence disseminating the scientific results, a strong international collaboration with two teams from South Africa, and about six undergraduate students from Northern Arizona University who will be heavily involved in the project.