Electrostatic field strength and

A quantitative estimation once again would require an estimation of the electrostatic field strength and its variation with particle size. This has been estimated previously [15], but since the electrostatic field strength is such a sensitive function of the distance normal to the surface, the calculation has little quantitative significance. 

The relation established between the electrostatic field strength and potential allows us to find dependence q>(r) knowing the function E(r) for all examples considered above. In fact, it follows from eqs. (4.1.26) and (4.1.27) that... 

Lux (1939) introduced the symbol pO (note it is not an exponent like pH) to quantify the acid-base balance in a glass, and various attempts have been made to obtain values for this parameter. All are based on the electronegativity of the cation or a related characteristic, such as electrostatic field strength (Volf, 1984). 

A major advantage of fluorescence as a sensing property stems from the sensitivity to the precise local environment of the intensity, i.e., quantum yield (excited state lifetime (xf), and peak wavelength (Xmax). In particular, it is the local electric field strength and direction that determine whether the fluorescence will be red or blue shifted and whether an electron acceptor will or will not quench the fluorescence. An equivalent statement, but more practical, is that these quantities depend primarily on the change in average electrostatic potential (volts) experienced by the electrons during an electronic transition (See Appendix for a brief tutorial on electric fields and potentials as pertains to electrochromism). The reason this is more practical is that even at the molecular scale, the instantaneous electric... 

In detail, the surface starts forming an oval under the influence of increasing field strength and in turn, a sharper curvature of the oval increases the field strength. When a certain field strength is reached, the equilibrium of surface tension and electrostatic forces becomes independent of the curvature s radius, and mathematically, the radius could become zero. However, in a real system infinite... 

Since CEC is a hybrid technique, the differential migration of analytes through the stationary phase bed will generally involve lipophilic, electrostatic, and electrophoretic processes between the analytes and the stationary and mobile phases. Consequently, the applied voltage and electrical field strength and the mobile phase properties such as pH, buffer concentration, ionic strength, temperature, and the organic content will all affect the separation. For a detailed discussion, also refer to reference 10. 

Spectra of type III are shown in Fig. 7. In all four cases these materials are metallic phases, having metallic luster and conductivity. Their spectra have an appreciable absorption coefficient at 0 ev., which may correspond to electrons being promoted to the Fermi level in the conduction band and very low amplitude of fine structure, i.e., relatively flat absorption plateaus. The low amplitude may be attributed to relatively low electrostatic field strength in the first coordination sphere, to be expected in these electronic... 

The slope of the line yields the average electrostatic field strength F of 2.7 X 10 e.s.u./cm. (at the operative distance from the rutile surface to the center of the dipole) this value is in excellent agreement with that calculated for rutile by de Boer (44) from the results for argon adsorption by Morrison, Los, and Drain (4 ). 

Average Electrostatic Field Strengths for Solid Adsorbents and Commercial Pigments from Heals of Immersion... 

The separation of compounds by ion exchange depends on the differences in electrostatic field strength around the sample ions and on the activity coefficients of the resin. However, these are not the only factors involved since many anomalies have been found. 

This is Coulomb s law. The units for charge, field strength, and force are made compatible by specifying the units of the factor of proportionality -y. For example, if y = 4-ir/e, where e is the dielectric constant of the medium, the units are in terms of cgs or absolute electrostatic system (esu). Since the dielectric constant for air is essentially 1, for aerosols using the cgs system of units, -y = 4u. 

Since the dielectric constant of a dipole is really a measure of the freedom of the dipole to become oriented in response to changes in electrostatic field strength, it would seem reasonable that the first layer of water molecules adsorbed to the charged surface (as the result at least of Van der Waals and London... 

The strength of the electrostatic field inside the cavity of the LiA, NaA, and especially CaA zeolites varies greatly. For different directions, the electrostatic field strength vector is often reversed in sign. 

It is evident that the presence of water (or perhaps of other proton donors) introduces ambiguities into the interpretation of catalytic results based on a series of cation-exchanged zeolites with different calculated (40,48) electrostatic field strengths. Although the water source could be an added promoter (49-51), it could also arise via elimination in alcohol dehydration, a reaction which is known (6,7,5i,5< ,56) to proceed smoothly over mono- and divalent cation-exchanged faujasites. 

Zettlemoyer, A.C., Chessick, J.J., and HoUabaugh, C.M. (1958). Estimation of the surface polarity of solids from heat of wetting measurements. Phys. Chem., 62, 489-90. Morimoto, T. and Suda, Y. (1985). Heat of immersion of zinc oxide in organic liquids. 1. Effect of surface hydroxyls on the electrostatic field strength. Langmuir, 1, 239—43. 

One must conclude as for the monovalent counterion sequences referred to in the Introduction that interaction between bivalent cations and anions is a complex phenomenon not determined solely by simple electrostatic considerations and ion size. Of the current hypotheses that explain ion sequences, that of Eisenman (45), based on anion field strength and recently expanded to include divalent cation effects (46, 47), seems the most comprehensive. However, we believe a fundamental understanding of these systems awaits better knowledge of the role of such factors as water structure, hydration, and geometric effects, including orientation associated with the presence of an alkyl group and of pH. Studies on a more extensive range of cations are required for all the cited systems, with the possible exception of those based on fatty acids. 

The study of carbon monoxide adsorption by Angell and Schaffer (6) has been discussed elsewhere (7, 74, 75). An interesting observation not previously emphasized is the appearance of cation specific absorption bands in the spectra of the multivalent cation zeolites because of the CO interacting with the exchanged cation via the carbon atom. They showed that the band frequency was a function of the electrostatic field strength which polarized the CO molecules. 

The DC properties of anti-static epoxy GFR pipes The use of glass-fibre reinforced (GFR) epoxy resin pipes is, especially in tankers, hampered by the bad electrostatic properties of these pipes. The possibility to decrease the volume resistivity to an acceptable level using only a small amount of carbon black (see 5.3.2) resulted in the development of the WAVIMAR anti-static GFR pipe system by Wavin BV. This pipe system is based on a liquid DGEBA/MDA (100/27) and cured for two hours at 120°C, containing about 1.5 %wt. (on the resin phase) of Ketjen black EC-2000 carbon black. The specific volume resistivity of a sample of such a pipe was measured as a function of the direction, the field strength and the pipe wall thickness. 

---