Porous flow

Iwamori H (1993) Dynamic disequilibrium melting model with porous flow and diffusion-controlled chemical equilibration. Earth Planet Sci Lett 114 301-313 Iwamori H (1994) U- °Th- Ra and Pa disequihbria produced by mantle melting with porous and channel flows. Earth Planet Sci Lett 125 1-16... 

Several models relating the isotopic effects of U-series disequilibria to the timescales of the melting process have now been proposed (e.g., McKenzie 1985 Williams and Gill 1989 Spiegelman and Elliott 1993 Qin 1992 Iwamori 1994 Richardson and McKenzie 1994). While these models differ mainly in their treatment of the melt extraction process (i.e., reactive porous flow vs near fractional melting), because they incorporate the effect... 

Dynamic melting models provide results that are similar to those obtained from the chromatographic porous flow melting model in that the extent of ( Ra/ Th)... 

In what follows, we present a simplified box-model that capture the essential of the chromatographic porous flow model with the only assumption that there is equilibration... 

Batch and equilibrium porous flow melting models... 

Figure 15. (a) Comparison of equilibrium porous flow (EPF Spiegelman and Elliott 1993) and dynamic melting (DM Williams and Gill 1989) models for Ra- °Th and activity ratios in... 

The limiting-current method has been used widely for studies in packed and fluidized beds (see Table VII, Part H). Limiting current measurements in these systems overlap in part with the design and analysis of packed-bed and fluidized-bed electrochemical reactors in particular the potential distribution in, and the effectiveness of, such reactors (for example, for metal removal from waste streams) is an extensive area of research, which cannot be covered in this review. For a complete discussion of porous flow-through electrodes the reader is referred to Newman and Tiedemann (N8d). 

Porous flow-through electrode design (coulometric or amperometric). 

Aliena, F. W. and Belfort, G. Chem. Eng. Sci. 39 (1984) 343. Lateral migration of spherical particles in porous flow channels application to membrane filtration. 

The various versions of the Cu ISE also include flow-through electrodes [36, 389], porous flow-through electrodes [290] and flow-through microelectrodes [407]. 

Goodfellow 2003 Gilliss et al. 2004). Interpretation of hydrology is simplified in regions dominated by porous flow in unconfined aquifers, and significantly more complicated where flow is fracture-dominated, or where significant density contrasts between different groundwater flow systems exist (Carey et al. 2003). 

Equations (5.95), (5.96) and (5.97) are suitable for constant critical melting porosity. In a one dimensional steady state melting column as a result of decompression melting, the porosity may increase from the bottom to the top of the column. If melting porosities change as a function of the spatial position, the related differential equations need to be solved numerically. More details of various melt transport models by porous flow have been given by Spiegelman and Elliott (1993), Iwamori, (1994), and Lundstrom (2000). 

For melt as porous flow, the enrichment factors due to melt transport over batch melting at variable depths in a one dimensional melting column are given by (5.95), (5.96) and (5.97). 

Transport Inviscid Newtonian non-Newtonian Porous Flow, Convection,... 

Anti-atrazine antibodies were coupled to a Si microchip comprising 42 coated porous flow channels. The porous Si layer was achieved by anodizing the channel in 40% HF/96% ethanol (1 1). Detection of atrazine was achieved in a competitive format. The chemiluminescence signal decreased when a known amount of horseradish peroxidase-labeled atrazine was added. This decrease was used to determine the amount of unlabeled atrazine in the sample [1030],... 

In order to get noble gas based paleotemperatures that represent the average annual temperatures, study areas should be remote from past snowmelt recharge areas, and they should include only systems that received recharge through thick enough aerated zones in which porous flow dominated. On the other hand, the seasonal variations that accompanied the climatic... 

The thickness of the aerated zone and the nature of its soil and rocks have to be established in terms of the lithologies, prevalence of conduit flow or porous flow, and absorption capacity. 

Experiments have shown that the solution - diffusion imperfection model fits data better than the solution - diffusion model alone and better than all other porous flow models.6 However, the solution-diffusion model is most often cited due to its simplicity and the fact that it accurately models the performance of the perfect RO membrane. 

To account for their distinctive characteristics, several authors (notably Peter Kelemen) suggested the formation of the layered refractory peridotites by olivine-forming, melt-rock reactions, leading to the evolution of porous-flow channels ... 

Fertilization may alternatively result from the fractional solidification of partial melts incompletely drained from residual mantle, upon cooling of melting domains due to mantle convection or tectonic upwelling. In this situation, the refertilized peridotites (sometimes associated with replacive pyroxenites—see Section 2.04.4.2.2) may dehne a layering interpreted in terms of high-porosity compaction waves or porous-flow channels (Obata and Nagahara, 1987 Van der Wal and Bodinier, 1996 Garrido and Bodinier, 1999). 

The paradox of the spatial decoupling between isotopic contamination and LILE and LREE enrichment was resolved with a numerical simulation of isotopic variations during reactive porous flow (Bodinier et al., 2004). This confirmed that the isotopic contamination (e.g., " Nd/ " Nd) by the infiltrated melt is restricted to the domain between the melt source ( = dike) and the chromatographic front of the element (neodymium)—i.e., —20 cm from the dike in the studied wall rock. Numerical experiments also showed that the fractional solidification of infiltrated melt (due to amphibole cpx precipitation) accounts for the systematic increase in thorium, uranium, LREE, and P2O5, that reach a maximum in the distal apatite-bearing wall rock (>50 cm from the... 

---