相关实验视频
Updated: Jun 21, 2025

08:01
The Diffusion of Passive Tracers in Laminar Shear Flow
Published on: May 1, 2018
8.5K
在不和多孔介质中溶液的混乱运输
Andrés Velásquez-Parra1,2, Federica Marone3, Michele Griffa4
1Department of Water Resources and Drinking Water, Swiss Federal Institute of Aquatic Science and Technology (Eawag), 8600 Dübendorf, Switzerland.
Environmental science & technology
|July 6, 2024
概括
降低多孔介质中的液体和度会增加混乱的溶液混合,即使流速缓慢. 这一发现对于了解未和土壤中的污染物运输和营养含量至关重要.
科学领域:
- 环境科学 环境科学
- 地质物理学 地质物理学
- 流体动力学 流体动力学
背景情况:
- 不和的多孔介质对于地下污染物的命运和营养的可用性至关重要.
- 控制这些复杂系统中溶液混合的机制尚未完全理解.
- 和度对混沌溶液混合的影响仍然未被探索.
研究的目的:
- 调查和在不和多孔介质中混乱溶液混合中的和的作用.
- 探索孔尺度异质性如何影响混合效率.
主要方法:
- 孔尺度流量和运输的三维数值模拟.
- 使用多孔介质的X射线断层图像,在不同的液体 (湿) 阶段和水平.
- 采用混乱指标,包括利亚普诺夫指数,以量化羽毛变形和混合.
主要成果:
- 在溶液羽毛变形和混合中观察到混乱的动态.
- 较低的和水平增强了混乱的动态.
- 即使在扩散占主导地位的条件下,混沌的混合也发生了,并且通过更高的流速来加强.
结论:
- 孔尺度的空间异质性,被空气等不可混合的相放大,显著影响不和多孔介质中的混合效率.
- 这项研究为评估这些环境中的混合和反应提供了基础.
- 这些发现对于理解地下污染物运输和营养循环至关重要.
相关概念视频
Transcellular Transport of Solutes
3.5K
Transcellular transport of solutes is the movement of substances like monosaccharides and amino acids through polarized cells. This transport mechanism is primarily seen in epithelial and endothelial cells aided by membrane transport proteins such as channels and transporters. The tight junctions between these cells confine the membrane proteins to the two sides of the cell. The epithelial cells have distinct apical and basolateral domains. In contrast, the endothelial cells show the luminal...
3.5K
Fluid Movement Between Compartments
505
The force applied by fluids against a surface, known as hydrostatic pressure, initiates the transfer of fluid among different compartments. Within our blood vessels, the blood's hydrostatic pressure is a result of the heart's pumping action. At the arteriolar end of capillaries, hydrostatic pressure (capillary blood pressure) exceeds the opposing colloid osmotic pressure created primarily by plasma proteins like albumin. This discrepancy in pressure propels plasma and nutrients from the...
505
Osmosis
5.2K
Osmosis is the movement of free water molecules through a semipermeable membrane. The water's concentration gradient across the membrane is inversely proportional to the solutes' concentration. Whereas diffusion transports material across membranes and within cells, osmosis transports only water across a membrane, and the membrane limits the diffusion of solutes in the water. Osmosis is a special case of diffusion.
Water, like other substances, moves from a high concentration of...
Water, like other substances, moves from a high concentration of...
5.2K
Facilitated Transport
125.3K
The chemical and physical properties of plasma membranes cause them to be selectively permeable. Since plasma membranes have both hydrophobic and hydrophilic regions, substances need to be able to transverse both regions. The hydrophobic area of membranes repels substances such as charged ions. Therefore, such substances need special membrane proteins to cross a membrane successfully. In facilitated transport, also known as facilitated diffusion, molecules and ions travel across a...
125.3K
The Significance of Membrane Transport
25.0K
The transport of solutes across the cell membrane is essential for metabolic processes, like maintaining cell size and volume, generating the action potential, exchanging nutrients and gases, etc. Membrane transport can be either passive or active. It can be simple diffusion, facilitated, or mediated transport aided by transport proteins such as transporters and channels.
Transporters facilitate either an active or passive movement of solutes. They can allow a single-molecule transport down its...
Transporters facilitate either an active or passive movement of solutes. They can allow a single-molecule transport down its...
25.0K
Entropy and Solvation
7.0K
The process of surrounding a solute with solvent is called solvation. It involves evenly distributing the solute within the solvent. The rule of thumb for determining a solvent for a given compound is that like dissolves like. A good solvent has molecular characteristics similar to those of the compound to be dissolved. For example, polar solutions dissolve polar solutes, and apolar solvents dissolve apolar solutes. A polar solvent is a solvent that has a high dielectric constant (ϵ...
7.0K

