Flow cell hollow

Sato S., Saito M. and Miyagi M., Infrared Hollow Waveguides for Capillary Flow Cells, Appl. Spectrosc., 1993 47 (10) 1665-1669. 

In fact, membranes generally serve as the main barrier to water flow into or out of plant cells. The interstices of the cell walls provide a much easier pathway for such flow, and hollow xylem vessels present the least impediment to flow (such as up a stem). Consequently, the xylem provides a plant with tubes, or conduits, that are remarkably well suited for moving water over long distances. The region of a plant made up of cell walls and the hollow xylem vessels is often called the apoplast, as noted above (Chapter 1, Section 1.1D and in Section 9.4A). Water and the solutes that it contains can move fairly readily in the apoplast, but they must cross a membrane to enter the symplast (symplasm), the interconnected cytoplasm of the cells. 

A series of papers concerning the use of immobilized enzymes in industrial reactors has been published.The operational effectiveness factors of immobilized enzyme systems have been described.Analytical expressions have been developed that allow the generation of effectiveness graphs for immobilized whole-cell hollow-fibre reactors. A theoretical method of determining the kinetic constants of immobilized enzymes in continuous stirred tank and plug-flow reactors by transformation of rate-equation variables has been presented. 

We solved the problem of isotope measurement in the effluent for HPLC by mixing coliamn effluent with liquid scintillation fluid and passing it through a hollow flow cell (Bakay, 1975a Bakay, 1975b Bakay, 1977). The quantitation of UV compounds and radioactivity was carried out simultaneously and was completed in 120 minutes. 

Figure 5 Frequently applied dialysis setups. (A) Thin layer flow cell, (B) immersion membrane probe, (C) hollow-fiber membrane module, and (D) immersing hollow-fiber membrane probe.

The concentration of viruses in water is much lower than that of bacteria therefore their preconcentration and separation from other suspended matter is important in virological analysis. Viruses may be enriched by UF by use of tangential-flow or hollow-fiber filtration units most suitable for preconcentration from large-volume water samples. Another possibility consists in adsorption of the viruses on the microfilter matrix followed by elution with diluents containing cell extracts, serum, or surfactants. 

Hollow fiber reactors [7] and dialysis reactors [8] avoid shear stress by separating cells and flowing media. In both reactors nutrient supply takes place by diffusion through the capillary wall or the dialysis membrane. 

The pitot tube is a device for measuring v(r), the local velocity at a given position in the conduit, as illustrated in Fig. 10-1. The measured velocity is then used in Eq. (10-2) to determine the flow rate. It consists of a differential pressure measuring device (e.g., a manometer, transducer, or DP cell) that measures the pressure difference between two tubes. One tube is attached to a hollow probe that can be positioned at any radial location in the conduit, and the other is attached to the wall of the conduit in the same axial plane as the end of the probe. The local velocity of the streamline that impinges on the end of the probe is v(r). The fluid element that impacts the open end of the probe must come to rest at that point, because there is no flow through the probe or the DP cell this is known as the stagnation point. The Bernoulli equation can be applied to the fluid streamline that impacts the probe tip ... 

Blood cells are separated from blood (hematocrit 40%) by microfiltration, using hollow-fiber membranes with an inside diameter of 300 pm and a length of 20 cm. The average flow rate of blood is 5.5 cm s T Estimate the filtrate flux. 

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