Internal indicator

Mention should be made of one of the earliest internal indicators. This is a 1 per cent solution of diphenylamine in concentrated sulphuric acid, and was introduced for the titration of iron(II) with potassium dichromate solution. An intense blue-violet coloration is produced at the end point. The addition of phosphoric(V) acid is desirable, for it lowers the formal potential of the Fe(III)-Fe(II) system so that the equivalence point potential coincides more nearly with that of the indicator. The action of diphenylamine (I) as an indicator depends upon its oxidation first into colourless diphenylbenzidine (II), which is the real indicator and is reversibly further oxidised to diphenylbenzidine violet (III). Diphenylbenzidine violet undergoes further oxidation if it is allowed to stand with excess of dichromate solution this further oxidation is irreversible, and red or yellow products of unknown composition are produced. 

Internal indicators suitable for use with cerium(IV) sulphate solutions include AT-phenylanthranilic acid, ferroin [1,10-phenanthroline iron(II)], and 5,6-dimethylferroin. 

Potassium chloride (nitrate) bridge 583, 582 Potassium chromate as indicator, 343, 349 Potassium cyanoferrate(II) D. of, (ti) 384 Potassium cyanoferrate(III) D. of, (ti) 399 Potassium cyanonickelate(II) prepn., 328 Potassium dichromate solution analyses involving, 375 oxidising properties of, 375 internal indicators for, 377 preparation of, 0.02M, 375 redox indicators for, 377 standardisation of, by iron, (cm) 546, (ti) 376... 

Neither the usual membrane ISEs nor the gas-sensing electrodes, in which their internal indicator electrode functions as a zero-current potentiometric half-cell, are under consideration here. 

International indicates that the amount of calcium silicate added to a package of table salt is less than one-half percent (by weight). in addition to adding calcium silicate to table salt, this anti-caking agent is also included in formulations of baking powder. 

III. Purpose Determine the initial rate of a chemical reaction using an internal indicator. Examine the dependence of the initial reaction rate upon the initial concentrations of the reactants. Find the reaction order, the partial orders, and the experimental rate constant of the reaction. 

When retracing Herman Mark s footsteps once quickly learns that his career, from meteoric rise to prominence in Germany to founding of institutes in Vienna and Brooklyn, has truly been international. Indicative is the fact that over the years he has had contact and often close interaction with a large percentage of the notable scientists of this century. 

The estimation of a vanadate solution by direct titration with ferrous sulphate or ferrous ammonium sulphate solution has been worked out, and is found to be specially applicable to the analysis of vanadium alloys. The vanadate is again reduced to tire tetravalent state by the ferrous salt, the end point being obtained by the use of potassium ferricyanide as internal indicator alternatively, a known excess of the ferrous salt solution is added to the vanadate, the amount unused... 

A few drops of a very dilute alcoholic solution may be used as an internal indicator. 

Methyl Orange.—Used as an internal indicator in acidimetry and alkalimetry. Turned red with acid and yellow with alkali. Can be used in the presence of carbonates to detect free alkali. Is acted upon by bicarbonate. 

Methyl Red.—Used as an internal indicator like methyl orange, but is more sensitive. 

If electrodynamics is a gauge theory with internal 0(3) gauge group symmetry, however, there are internal indices and the vector potential becomes... 

In HeLa cells, the di-ferric transferrin-stimulated proton release is accompanied by an increase in the pH inside the cell as measured by change in fluorescence of the internal indicator BCECF incorporated into the cells (Figure 7). This alkalinization is consistent with exchanger activation to export protons. Most of the internal pH increase is inhibited by amiloride or dimethylamiloride (Mrkic et al., 1992 Yun et al., 1993). The internal change in pH is prevented if Cs+ is substituted for Na+ or Li+ in the external media (Toole-Simms, 1988). Ferricyanide-stimulated proton release by HeLa cells is not accompanied by an internal pH increase. The basis for this difference from di-ferric transferrin has not been investigated. It is possible that the rapid electron transport in response to ferricyanide leads to oxidation of sufficient NADH, which produces protons inside the cell, to counter... 

Because the characteristic blue color of the starch-iodine complex is not formed at high concentrations of hydrochloric acid, starch is not a suitable indicator. Andrews used a few milliliters of an extraction solvent such as carbon tetrachloride or chloroform to obtain a highly sensitive end point. The main disadvantage is the inconvenience of shaking the reagent with the extraction solvent after each addition near the end point. As internal indicators, amaranth, brilliant ponceau, and / -ethoxychrysoidin have given the best results. 

Summations are included over all internal indices—that is, all indices associated with lines that begin and end at operator interaction lines and do not extend to infinity above or below the diagram like the external lines described above. Thus, the present diagram requires a summation over indices i and a. 

Precipitation of silver azide from acetate solution and gravimetric determination of the silver as silver azide or silver chloride, or volumetrically by addition of an excess of standard silver nitrate solution and back-titration with standard ammonium thiocyanate using ferric alum as internal indicator. 

The internal indicators are also divided into the following groups according to their use in different types of reactions. 

The effect of pH changes on the potency of local anesthetics has been extensively investigated (30). Based on these studies, it was concluded that local anesthetics block the action potential by first penetrating the nerve membrane in their un-ionized forms and then binding to a site within the channels in their onium forms. Perhaps the most direct support for this hypothesis comes from the experimental results of Narahashi et al. (31,32), who studied the effects of internal and external perfusion of local anesthetics (both tertiary amines and quaternary ammonium compounds), at different pH values, on the sodium conductance of the squid axon. The observation that both tertiary amines and quaternary ammonium compounds produce greater nerve blockage when applied internally indicates an axoplasmic site for these compounds. 

Based on the fuzziness of coal spontaneous combustion standard, it is reasonable to use the membership which is determined by membership function division classification boundary. Combined with moisture, ash, volatile, sulfur, a total of 4 internal indicators on effect of coal spontaneous... 

To select moisture, ash, volatile and sulfur 4 internal indicators which influent port storage of spontaneous combustion, can be used to evaluate the spontaneous combustion tendency of port coal storage. Geological conditions and external factors have little use to coal spontaneous combustion tendency of port, so it does not take into account in the selection factors. 

The indicators included in RSDI measure road safety development in terms of direct (output or ends) and indhect (means or input). The direct indicators are derived measures e.g. fatalities rates (traffic risk and personal risk) and they are considered as good measures for explaining national road safety development. The indirect indicators are individual means in the way they can describe the development in a particular relevant theme to road safety. Many international indices include both terms in the same index. For example, the Composite Health Index includes infant mortality rates as an ou ut (dhect) indicator of health index. 

There are few indicators that are already widely used in international indices which will make RSDI easy to understand and more valid. The UNDP has considerable resources to decide which indicators to use in the HDl and determine best practices from different sources and countries. The examples used in the RSDI contexts and taken from HDI are Life expectancy (years) , Adult literacy rate and Gross domestic product per capita . However, Life expectancy alone is not enough to measure the health level. One needs to make the selection more specific. 1 therefore added severity index to this dimension (health level). As discussed earlier, the severity index decreases with better medical facilities and rescue services. 

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