Wall-tube cell

Reference electrodes constructed similar to high-pressure pH sensors have been proposed, among them internal [209, 252-254] as well as external types [205, 255]. Cell design [257-260] suited for extreme conditions has been given, especially a wall-tube cell [259] (Fig. 3.9). 

Fig. 3.9 Lc/t High-temperature-high-pressure electrochemical wall-tube cell (A) inlet, (B) pre-cell, (C) mixing dishes, (D) platinum resistor, (E) reference electrode, (F) counter electrode, (G) zircaloy nozzle, (H) outlet, (I) working electrode, (J) cell and (K) zircaloy rings. Right Typical voltammograms in Fe /Fe 1 mM in 0.2 M Na2S04 (pH 1.5) on a platinum electrode at 85 °C. Sweep rate 50 mV s, H 0.264 cm, d 0.204 cm and = 0.05 cm. Flow rates (a) 4, (b) 8, (c) 12 and (d) 20 cm min. From [259], with permission...

In the wall jet cell the column effluent obtains a high linear velocity because it is accelerated by narrowing the inlet tube. 

The rectangular frame in Fig. 10a enables a similar mixing quality in the cell chamber as in the cell of Fig. 9 (for reduced mixing requirements less tubes are sufficient). Ring-shaped frames as shown in Fig. 10b can be particularly easy machined by turning, or simply can be cut from thick-walled tubes, including glass. 

The biochemical similarities of leaf and stem rust elicitors, the missing gene specificity of both elicitors, the fact that an equally active elicitor was isolated from germ tube cell walls of oat crown rust (60), together with the described reactions of different non-hosts to the stem rust elicitor led us to speculate that the isolated elicitors may play a role in the induction of general mechanisms of non-host resistance (130). Although they may be involved in the elicitation of race-cultivar specific resistance as well, race-cultivar specificity in the wheat-stem rust system clearly cannot be explained on the basis of the specificity of the isolated elicitors. One possible explanation would be the occurrence of race-cultivar specific suppressors of the resistance reaction (124,131,132). 

Figure 4.19 — (A) Detail of a wall-jet cell in (Al) top view and (A2) side view (1,2) Perspex blocks (3) contact wire (hook) (4) CHEMFET (5) glass (6) ring (7) PTFE tubing. (B) Side view of the flow-through cell (1,2) Perspex blocks (3) contact wire (4) CHEMFET. (Reproduced from [151] with permission of Elsevier Science Publishers).

This value is corrected by 15cm for the cell-wall area, as estimated from the cell dimensions. Desorption peaks from an empty U-tube cell gave areas of 12-17 cm. ... 

Two complex tissues, the xylem and phloem, provide the conducting network or "circulatory system" of plants. In the xylem or woody tissue, most of the cells are dead and the thick-walled tubes (tracheids) serve to transport water and dissolved minerals from the roots to the stems and leaves. The phloem cells provide the principal means of downward conduction of foods from the leaves. Phloem cells are joined end to end by sieve plates, so-called because they are perforated by numerous minute pores through which cytoplasm of adjoining sieve cells appears to be connected by strands 5-9 pm in diameter.154 Mature sieve cells have no nuclei, but each sieve cell is paired with a nucleated "companion" cell. 

Fig. 9. Typical wall-jet cell, A, Disc electrode contact B, ring electrode contact C, Ag/AgCl reference electrode D, Pt tube counter electrode E, cell inlet F, Kel-F cell body. (From ref. 44.)...

Place 5 mg of dried cell walls or cell-wall fractions (uNrr E3.i) into a scrupulously clean (see Critical Parameters) borosilicate glass tube (in duplicate). Record the exact weight of cell walls or fractions. 

Weigh 5 mg (record exact weight) of cell walls or cell-wall fraction (in duplicate) into borosilicate glass tubes (see unit E3.i for cell wall preparation and cell-wall fractionation). 

Gabrielli and Perrot [23] carried out in situ mass measurements in well-defined flowing electrolyte with an electrochemical quartz crystal microbaiance (EQCM) adapted to a submerged impinging jet cell (wall tube configuration). The authors employed this new device for the study of nickel electrodeposition and evaluation of the cathodic efficiency. Under the conditions of their experiment (nozzle diameter d = 7 mm disc electrode diameter de = 5 mm and nozzle-to-electrode distance H = 2d), the current that flows at the electrode increases with the square root of flow rate (0-10 cm3 s"1). It should be noted that this approach is much simpler to implement than the rotating EQCM, while keeping control of the convective-diffusion conditions. 

Hydrodynamic electrodes — are electrodes where a forced convection ensures a -> steady state -> mass transport to the electrode surface, and a -> finite diffusion (subentry of -> diffusion) regime applies. The most frequently used hydrodynamic electrodes are the -> rotating disk electrode, -> rotating ring disk electrode, -> wall-jet electrode, wall-tube electrode, channel electrode, etc. See also - flow-cells, -> hydrodynamic voltammetry, -> detectors. 

Figure 5.7 Three-dimensional drawing of the experimental system used to assess the catalytic properties of the amorphous iron silicate smokes. The (smoke) catalyst is contained in the bottom of a quartz finger (attached to a 2L Pyrex bulb) that can be heated to a controlled temperature. A Pyrex tube brings reactive gas to the bottom of the finger. The gas then passes through the catalyst into the upper reservoir of the bulb and flows through a copper tube at room temperature to a glass-walled observation cell (with ZnSe windows) in an P iiR spectrometer. From there, a closed-cycle metal bellows pump returns the sample via a second 2L bulb and the Pyrex tube to the bottom of the catalyst finger to start the cycle over again (Hill and Nuth 2003).

The Pericarp or ripened ovarian wall which, alike with all other grains, adheres firmly to the wall of the seed forming a portion of the skin of the grain. The pericarp comprises an outer epicarp of elongated cells with thin cuticle, a mesocarp of thicker walled cells without, becoming thinner within, and a layer of tube cells. 

Uromyces phaseoli (Germ tube cell walls) SCB 1 13 1 (70)... 

Trunec has described the thermoplastic extrusion of thin-wall tubes made of yttria-stabilized zirconia and gadolinia-doped ceria [Tru 04], These ceramics are used for solid oxide electrolyte applications, e.g. solid oxide fuel cells. The thermoplastic binder system used consists of ethylene-vinyl acetate copolymer, parafHn wax and stearic acid. With this system tubes with an outer diameter of 10.5 mm and wall thicknesses of 290 and 280 pm could be fabricated. 

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