Unsaturated water flow through thin porous layers plays an important role in many applications such as water management in hydrogen fuel cells and hygiene products. It is well known that void spaces between adjacent thin layers (i.e., layer-layer interfaces) considerably impact through-plane water infiltration. Therefore, it is essential to account for this fact in the …
Single-sided NMR with the NMR-MOUSE is employed for the characterization of fluids in fibrous and open foam materials. One of the key aspects of this study is the quantification of the fluid amount. To this end critical information was provided by a relaxation study. Using 2 mM/L of a Gd3+ relaxation agent the repetition time could be shortened to …
Macroscale three-dimensional modeling of fluid flow in a thin porous layer under unsaturated conditions is a challenging task. One major issue is that such layers do not satisfy the representative elementary volume length-scale requirement. Recently, a new approach, called reduced continua model (RCM), has been developed to describe multiphase fluid flow in a stack of …
Offering multifaceted applications, thin fibrous porous materials are mostly used in stacks of layers, each layer having a defined functionality. Since only a few pores exist across a layer a couple of hundred microns thick, the interface between layers may significantly affect liquid ingress. Thus, the main objective of the study is to substantiate that …
The conservation of historical buildings and outdoor cultural assets is of great value for the humankind. In this context, consolidation treatments represent a fundamental procedure to assure the survival of deteriorated cultural artefacts. For porous materials characterized by a wide distribution of pore sizes, adequate consolidation treatments require a product with a sufficient penetration depth and homogeneous …
The diffusion of alkaline chlorides (LiCl, KCl, and CsCl) and water in mesoporous silica samples with pore sizes covering the range from micropores (2 nm) up to mesopores larger than 30 nm have been measured by resorting to a simple diffusional technique in the case of electrolytes and 1H NMR in the case of water. The …
Evaporation kinetics of water confined in hierarchal polymeric porous media is studied by low field nuclear magnetic resonance (NMR). Systems synthesized with various degrees of cross-linker density render networks with similar pore sizes but different response when soaked with water. Polymeric networks with low percentage of cross-linker can undergo swelling, which affects the porosity as …
Spatially Resolved Monitoring of Drying of Hierarchical Porous Organic Networks Read More »
Taking a relaxed approach : The NMR relaxation behavior of imbibed solvent has been used to estimate the surface area of a variety of microporous metal–organic frameworks and zeolites. This NMR technique is amenable to automation and can expedite the characterization of microporous materials by identifying any nonporous or low‐surface‐area structures. Chen, Joseph J., et al. …
Ex Situ NMR Relaxometry of Metal-Organic Frameworks for Rapid Surface-Area Screening Read More »
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