Streaming of Electrolyte

Brush plating is a special technique which dispenses with a container and uses a swab soaked in electrolyte applied to the work. In jet plating a stream of electrolyte is applied to the cathode. Both are methods of selective plating, applying an electrodeposit to only a part of an article. Little has been published about the techniques or the properties of coatings they produce. 

Fluid bed electrodes consist of a bed of particles supported by a structure such as a coarse sinter and fluidized by an upward stream of electrolyte and two different configurations have been described where the current path is parallel or perpendicular to the direction of fluidization (Backhurst et al., 1969). Such electrodes have been used for electrosynthetic reactions and, in particular, a pilot plant for the reduction of... 

Many 2D planar structures have been used to implement deflection (continuous flow) electrophoresis. The primary requirement is that flow and electrophoresis be carried out simultaneously and uniformly. Hanging paper curtains soaked with electrolyte and fed a stream of electrolyte from above served admirably for this purpose when the technique was initiated in the 1950s. In recent years thin flow channels enclosed between flat plates have become important. The process is complicated by parabolic flow, which distorts and effectively broadens the electrophoretic zones. More detail is available in the cited references on electrophoresis [3-5]. 

Indeed, even nonequilibrium systems do not necessarily show measurable excess noise and, thus, deviate from relation 1. An appropriate example that is relevant to the subject is a capillary channel that contains a stream of electrolyte maintained by an external pressure difference. Measurements on several aqueous polymer solutions with added electrolytes performed at up to 5000 dyn/cm2 shear stresses and zero external voltage showed that measurable excess noise can be observed only for non-Newtonian solutions exhibiting elasticity (19, 20). Similar results were obtained for colloid suspensions... 

This procedure represents a preparative version of zone electrophoresis. The apparatus and technique has been previously elaborated [294,295] separation itself is carried out either in a stream of electrolytic solution or on a sheet of cardboard (curtain electrophoresis). In the free flow version the separation is carried out in a cell formed by two parallel glass plates (50 x 50 cm) situated 0.5-1.0 mm apart. It is necessary to ensure an equal and laminar flow of the electrolyte, which is carried out by feeding the buffer through a multichannel peristaltic pump. The sample is continuously applied in the middle near the upper edge of the cuvette (or paper sheet). The electrophoretic separation occurs transversally between vertical electrodes located on the right and left hand side of the separation cuvette (Fig. 6.33). The separated fractions are collected at the lower end of the cell by a system of small communicating vessels or by a multi-channel pump. In the version using paper the... 

When maxima are observed on polarographic curves, gelatin or other surface active substances are sometimes added to the solution. The concentration of surface active substance should be as low as possible, because a higher concentration of gelatin, deforms the polarographic curve. The surface active agent damps the streaming of electrolyte around the polarized mercury drop. 

In atomization, a stream of molten metal is stmck with air or water jets. The particles formed are collected, sieved, and aimealed. This is the most common commercial method in use for all powders. Reduction of iron oxides or other compounds in soHd or gaseous media gives sponge iron or hydrogen-reduced mill scale. Decomposition of Hquid or gaseous metal carbonyls (qv) (iron or nickel) yields a fine powder (see Nickel and nickel alloys). Electrolytic deposition from molten salts or solutions either gives powder direcdy, or an adherent mass that has to be mechanically comminuted. 

In the atomizing process, a stream of molten zinc is broken into tiny droplets by the force of a pressurized fluid impinging on the stream. The fluid can be any convenient material, although air is normally used. The atomized drops cool and soHdify rapidly in a coUection chamber. The powder is screened to specified sizes. Particulate zinc is also produced by other methods such as electrolytic deposition and spinning-cup techniques, but these are not of commercial importance. 

A Perkin-Elmer 5000 AAS was used, with an electrically heated quartz tube atomizer. The electrolyte is continuously conveyed by peristaltic pump. The sample solution is introduced into the loop and transported to the electrochemical cell. A constant current is applied to the electrolytic cell. The gaseous reaction products, hydrides and hydrogen, fonued at the cathode, are flowed out of the cell with the carrier stream of argon and separated from the solution in a gas-liquid separator. The hydrides are transported to an electrically heated quartz tube with argon and determined under operating conditions for hydride fonuing elements by AAS. 

The reduction of the sample was made at 2250 K In a flowing stream of hydrogen carrier gas ( SO cm /mln). The total pressure of the carrier gas was approximately 1 atm. The water vapor produced during the reduction was swept by the carrier gas Into an electrolytic-type (P2O5) moisture monitor and a continuous recorder trace of the water concentration as a function of time was obtained. A typical plot of the moisture content of the carrier gas as a function of time Is shown In Figure 3. The region on the left side of this figure where the moisture content... 

Membrane process for recovery of valuable organic chemicals from aqueous waste streams containing electrolytes... 

Important inherent characteristics of an enzyme that should be considered are the substrate affinity, characterized by the Michaelis constant the rate of turnover fecat> providing the catalytic efficiency fecat/ M. and the catalytic potential. Several attempts to compare enzyme catalysis with that of platinum have been published. Direct comparisons are difficult, because enzyme electrodes must be operated in aqueous electrolyte containing dissolved substrate, whereas precious metal electrodes aie often supplied with a humidified gaseous stream of fuel or oxidant, and produce water as steam. It is not straightforward to compare tme optimal turnover rates per active site, as it is often unclear how many active sites are being engaged in a film of enzyme on an electrode. 

The next focus is on the electrolyte-concentration cells with a liquid junction. The dilution of HC1, which was the subject of the discussion above, can also be realized in a cell with a liquid junction, as shown in Figure 6.13. It is presupposed that the two HC1 solutions of different concentration can be brought together and averted from mixing. The flowing of two streams of solution synchronously sometimes attains this. One then can establish the cell ... 

Stable, conductive electrodes would also be a problem. Preliminary experiments, were carried out in a cell, using simulated flue gas nearly identical to that shown in Fig. 24. In these tests, the membranes were hot-pressed from mixed powders of electrolyte (ternary eutectic of [Na, Li, K]2 S04) with LiA102 as matrix. The electrodes were constructed of cold-pressed Li20-9Cr203, partially sintered to give a highly-porous gas-diffusion structure. The tests were encouraging up to 50% of the S02 was removed from the simulated flue gas with the application of current. Simultaneously, a stream of concentrated S03 and Oz was evolved at the anode. 

Metallic powders are made several different ways. They can be prepared by reducing salts in a stream of a reducing gas, such as hydrogen chlorides of metals are commonly used but oxides are used too. Thermal decomposition in a vacuum of metal carbonyls or metal salts of organic acids, such as formates, produces metal powders. Surface areas of such powders are around 1.5 m2/g. Powders can also be made from electrolytic reduction of salts in organic solvents and by atomization of the metal. 

The excess electrolyte is blown off the electrode with a stream of pure Ar. 

Fuel cells are electrochemical systems that convert the energy of a fuel directly into electric power. The design of a fuel cell is based on the key components an anode, to which the fuel is supplied a cathode, to which the oxidant is supplied and an electrolyte, which permits the flow of ions (but no electrons and reactants) from anode to cathode. The net chemical reaction is exactly the same as if the fuel was burned, but by spatially separating the reactants, the fuel cell intercepts the stream of electrons that spontaneously flow from the reducer (fuel) to the oxidant (oxygen) and diverts it for use in an external circuit. 

Further experiments with the coated electrode suggests that the surfactant bipyridiniums are mobile within the mercaptan monolayer. If the electrode is transferred to a fresh electrolyte, the coverage (measured at 0.1 V/s) greatly diminishes. Likewise rinsing the coated electrode with a stream of pure water between cyclic voltammograms removes most of the electroactive bipyridiniums. 

In 1980 Bemhardsson et introduced an automated electrochemical method for CPT determination. The specimen is mounted as described in Section IV.2 (ii) using a stream of argon to avoid crevice corrosion and 0.02-5% sodium chloride as electrolyte. The CPT is determined by a potentiostatic test method using an instrument called the Santron CDT 400 for potential control, temperature control, and current measurements. 

For the purposes of discussion, we distinguish between two types of electric conductance metallic and electrolytic, the first being a stream of electrons, as in a copper wire, the second being a stream of ions, as in the case of a salt solution in water. In this case, positive ions will drift in the direction of the cathode, whereas negative ions will drift in the direction of the anode. 

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