Voltage applied

The flow rate will determine the amount of solution which will be used for electrospinning. For a certain voltage, there is a corresponding flow rate which maintains the stability of Taylor cone. If the flow rate is increased, there will be a corresponding increase in the fiber diameter or bead size. This is apparent as there 

Several other reports on electrospinning of bisphenol-A polysulfone/ DMAC (Yuan et al. 2004), hydroxypropyl, cellulose/ethanol or propanol 

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Corrosion protection of metals can take many fonns, one of which is passivation. As mentioned above, passivation is the fonnation of a thin protective film (most commonly oxide or hydrated oxide) on a metallic surface. Certain metals that are prone to passivation will fonn a thin oxide film that displaces the electrode potential of the metal by +0.5-2.0 V. The film severely hinders the difflision rate of metal ions from the electrode to tire solid-gas or solid-liquid interface, thus providing corrosion resistance. This decreased corrosion rate is best illustrated by anodic polarization curves, which are constructed by measuring the net current from an electrode into solution (the corrosion current) under an applied voltage. For passivable metals, the current will increase steadily with increasing voltage in the so-called active region until the passivating film fonns, at which point the current will rapidly decrease. This behaviour is characteristic of metals that are susceptible to passivation. 

In tlie polarization curve of figure C2.8.4 (solid line), tlie two regimes, activation control and diffusion control, are schematically shown. The anodic and catliodic plateau regions at high anodic and catliodic voltages, respectively, indicate diffusion control tlie current is independent of tlie applied voltage and7 is reached. 

Figure C2.8.4. The solid line shows a typical semilogaritlimic polarization curve (logy against U) for an active electrode. Different stages of reaction control are shown in tlie anodic and catliodic regimes tlie linear slope according to an exponential law indicates activation control at high anodic and catliodic potentials tlie current becomes independent of applied voltage, indicating diffusion control.

The situation in figure C2.8.5(b) is different in that, in addition to the mechanism in figure C2.8.5(a), reduction of the redox species can occur at the counter-electrode. Thus, electron transfer tlirough the layer may not be needed, as film growth can occur with OH species present in the electrolyte involving a (field-aided) deprotonation of the film. The driving force is provided by the applied voltage, AU. 

McKillop and associates have examined the electrophoretic separation of alkylpyridines by CZE. Separations were carried out using either 50-pm or 75-pm inner diameter capillaries, with a total length of 57 cm and a length of 50 cm from the point of injection to the detector. The run buffer was a pH 2.5 lithium phosphate buffer. Separations were achieved using an applied voltage of 15 kV. The electroosmotic flow velocity, as measured using a neutral marker, was found to be 6.398 X 10 cm s k The diffusion coefficient,... 

In the laboratory, it has been found that similar effects can be produced if a voltage is applied between two electrodes immersed in a gas. The nature of the laboratory or instrumental discharge depends critically on the type of gas used, the gas pressure, and the magnitude of the applied voltage. The actual electrical and gas pressure conditions determine whether or not the discharge is called a corona, a plasma, or an arc. 

The colors shown in Table 6.1 are only approximate. Sometimes mixtures of colors are seen as gas pressure or applied voltages change or if impurities are present. 

In Figure 6.4, the two electrodes are marked as cathode and anode, arising from the application of an external voltage between them. Before any discharge occurs, the electric-field gradient between the electrodes is uniform and is simply the applied voltage divided by the their separation distance, as shown in Figure 6.7. 

The exact conditions of gas pressure, current flow, and applied voltage under which the discharge occurs determine if it is of the corona, plasma, or arc type. The color of the emitted light may also change, depending not only on the type of gas used but also on whether it is a corona, plasma, or arc discharge. 

Under certain conditions the sample is clearly visible throughout the process. Other times it is necessary to stain the matrix to visualize the components. In cases where a final staining procedure is required, a small amount of dye is often added to the sample before the analysis. The dye typically migrates faster than any sample component. The position of the dye in the matrix indicates the speed of the resolution of the components of the sample. Typically, the electrophoretic medium is discarded after use. Good resolution can be obtained from 1 to 20 hours, using applied voltages of 10 to 2000 V and currents of 5 to 100 m A. 

Applied voltage Gos density Ion mobility Oust thickness Sectionolizotion Collection oreo Wire rodius Collector rodius... 

E = applied voltage, V V = counterelectromotive force (generated voltage), V R = armature resistance, H I = armature current, A k = constant dependent on motor design n = speed, r/min ( ) = magnetic-field flux... 

Electrolysis applied voltage = 10 V, AcONa, AcOH K2CO3, MeOH, H2O, 80-95% yield."... 

This depends upon the applied voltage, i.e. type of switching, starting torque of the motor, counter-torque... 

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