Total current profiles

Figure 7.6 Total ion current profile of the acidic fraction of a sample from a linseed oil reference paint layer (Opificio delle Pietre Dure, Florence, Italy), after saponification and silylation of carboxylic and hydroxyl ic groups [9]...

Figure 6.14. Cell Voltage vs. Cell Current profile of a hydrogen - oxygen fuel cell under idealized (dotted-dashed curve) and real conditions. Under real conditions the cell voltage suffers from a severe potential loss (overpotential) mainly due to the activation overpotential associated with the electroreduction process of molecular oxygen at the cathode of the fuel cell. Smaller contributions to the total overpotential losses (resistance loss and mass transport) are indicated.

Figure 12. Total ion-current profiles obtained with LC-MS, moving-belt interface, for the detection of carbamates and other pesticides. (Reproduced with permission from reference 53. Copyright 1982 Preston Publications.)...

GC-MS runs were stored as files by the data system on discs FORTRAN routines were written to compare selected parameters in file sets and to reduce the data to summary tables for hard copy output. These routines facilitated the determination of peak areas of components in extracted ion current profiles (EICP) for both total and selected ion chromatograms, calculated the removal of components of interest (e.g., those containing halogen isotopes) by treatment processes (GAC, CI2) or derivatization, summarized the occurrence of new components of interest in treatment or derivatization, and calculated the percent of the total ion current represented by a given component. The programs allowed operator discrimination between major and minor components in a file set by preselection of an ion current threshhold for data reduction. For data summarized herein, components were >4000 ion counts, which corresponds to a level >5 of the internal standard (decachlorobiphenyl) response. 

The details of the calculation of the voltammetric profiles can be consulted in the specialized literature8. Here we give the expression for a reversible reaction in which only the adsorbed species O and R contribute to the total current. The reason for this is to enable a comparison between the expressions for this situation and for thin-layer... 

The resolution criteria must be evaluated using measurements made on the selected ion current profile (SICP) for the appropriate ions for each isomer. Measurements are not made from total ion current profiles. 

Figure 3. Capillary GC-total ion current profile of Tenax-bound tobacco stalk headspace volatiles.

Oversimplifications of the mathematical treatment usually lead to nonuniform current distributions, but in this case, since the values of Dt and C° are not so high, the current profile is nonuniform for low overpotentials. When we are at large overpotentials, the situation is totally opposite, since we approach the limiting current. 

Figure 2. A comparison of total ion current profiles (TICPs) of a dock tar and sediment. Numbers refer to compound identifications presented...

Considering the practically important case of fixed total current Itot and A (galvanostatic regime under constant oxygen stoichiometry), the profile (6.57) provides invariance of I,ot with time. Indeed,... 

The system (6.108), (6.110), (6.111) determines oxygen, water vapour and local current density profiles along the channel in the case of constant A. The parameter E is iterated so that the local current density j gives the prescribed total current density... 

Figure 1 LC/ESI-MS analysis of oxidized PtdCho in oxidized LDL. Total positive ion current profile of oxidized LDL (A) single ion plots of representative PtdCho oxidation products. Peak identification is as given in figure. LDL was oxidized by incubation with 5pmoll CiS04 in 0.1 moll phosphate buffered saline (PBS) for 12h at 37°C. The total lipid extract of the oxidized LDL was dissolved in chloroform/methanol (2 1, v/v) and 20 pi of the sample containing 10 pg lipid was analyzed. Structural assignment for aldehydes and hydroperoxides are according to reference standards. Ions 832 and 830 were identified on the basis of retention time and molecular weight. Reproduced with permission of publisher from Ravandi A, Kuksis A, and Shaikh NA (2000) Arteriosclerosis, Thrombosis, and Vascular Biology 20. 467-477.

Figure 3.22 shows the total displacement values that occur in membrane (slice contom plots) and the deformation shape of the membrane (scale enlarged 180 times) for three different nominal current densities. It can be seen that the total displacement and the degree of the deformation in membrane are directly related to the increasing of current density, due to increasing of heat generation. In addition, the total displacement profile correlate with the Mises stresses. The deformation that occurs in membrane under the land areas is much smaller than under the channel areas due to the clamping force effect. 

Fig. 2.17 - (a) The potential-time profile for differential pulse polarography. Also shown schematically, (b) the charging current-time dependence (c) the Faradaic current-time dependence, and (d) the time-dependence of the total current. 

Figure 4.30 (a) Evolution of local current density profile upon variation of the total current J (indicated) in the cell. Solid lines—anal3dical solution (4.243) of reduced system, and dashed lines—numerical solution of the full system of equations (4.197), (4.198) and (4.233). Parameters are = 1, A = 100, = 8, p = 1, and 7 = 2. The other parameters required... 

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