Specific conductance experiments

Rowell and co-workers [62-64] have developed an electrophoretic fingerprint to uniquely characterize the properties of charged colloidal particles. They present contour diagrams of the electrophoretic mobility as a function of the suspension pH and specific conductance, pX. These fingerprints illustrate anomalies and specific characteristics of the charged colloidal surface. A more sophisticated electroacoustic measurement provides the particle size distribution and potential in a polydisperse suspension. Not limited to dilute suspensions, in this experiment, one characterizes the sonic waves generated by the motion of particles in an alternating electric field. O Brien and co-workers have an excellent review of this technique [65]. 

A radioactivity detector is used to measure radioactivity in the HPLC eluent, using a flow cell. The detection principle is based on liquid scintillation technology to detect phosphors caused by radiation, though a solid-state scintillator is often used around the flow cell [17,31]. This detector is very specific and can be extremely sensitive. It is often used for conducting experiments using tritium or C-14 radiolabeled compounds in toxicological, metabolic, or degradation studies. 

Since there is a close correlation between the specific conductivity of the catalytic solutions and the DP of the polymers formed in them, it follows that the electrochemical nature of the solutions must be largely unaffected by the polymerisation. Therefore at most a small fraction of the solute can be involved with the growing chain, and the remainder must be unaffected by the initiation of the polymerisation. This conclusion is strongly supported by the fact that in typical experiments the number of moles of polyisobutene formed was several powers of ten smaller than the number of moles of catalytic complex. 

Recently, new sorption experiments have been conducted with marine sediments [30] and microalgae [31]. Specifically these experiments have... 

It is difficult to obtain how the diffusivity depends on concentration using the bulk mass loss or gain method, although it is possible to verify specific concentration dependence by conducting experiments from small degrees of mass loss to almost complete mass loss (Wang et al., 1996). On the other hand, the shape of diffusion profiles reveals the dependence of diffusivity on concentration. 

The original specific heat experiments on BaPb xB Og by Methfessel et al (60) immediately raised the prospect that an unusual mechanism was operative in this newly found system. Their finding of no heat capacity anomaly at Tc could actually have a number of possible interpretations, including an impurity phase giving rise to superconductivity, a non-phonon mechanism, or some new form of conductivity. 

A large number of oxides which are commonly solid insulators at room temperature (e.g., A1203) yield highly conducting (specific conductance > 10 ohm-1 cm-1) melts on fusion. Some of these melts are undoubtedly ionic conductors whereas others are electronic conductors. It is, however, not always possible to differentiate between these two general types since both mechanisms may be operative to comparable extents at a particular temperature. Relatively few experiments have been reported in which reliable estimates of the transport numbers of either ions or electrons could be made. The subdivision in this section into the two general types of conductors is thus not to be interpreted as rigid. 

The specific conductivity of a large number of oxide melts is in excess of 1 ohm-1 cm-1 and the temperature coefficient of conductance is positive. Two types of experiments from which conclusions are drawn regarding the mechanism of conduction are to be found in the literature. In one, the applicability of Faraday s laws is directly tested. In the second case, the conductivity of both the crystalline solid up to the melting point and that of the melt is measured if the change in specific conductivity on fusion is negligible, and if the so-called activation energy EK defined by... 

The observed diffusion and reaction rate coefficients can be obtained from specific experiments. To quantify the rate coefficients on the right-hand side of Eq. (5.23), kinetic experiments could be conducted such that the global rate is preferably determined by FD, PD, or CR. In the laboratory these steps can be simulated separately by conducting experiments using static, stirred, or vortex batch adsorption systems (Ogwada and Sparks, 1986b). Therefore, to these systems one can assign additive resistance relations as follows ... 

At present we are conducting experiments with XIX, XX, and other flavins with crude hydrogenase (quite air labile) kindly provided by Wolfe. Initial results demonstrate ready reduction of biological and synthetic Fo (XX) at approximately 200 nmol/min/mg while the 7-methyl compound, XIX, is reduced tenfold more slowly (at equivalent 20fiM concentration). Studies are underway to investigate ratedetermining steps, flavin specificity, stereochemistry, and mechanism of redox transfer between H2 and F420 as well as its reoxidation by NADP. 

In their studies of conductance of the methylbenzenes in anhydrous hydrofluoric acid, Kilpatrick and Luborsky (96) found that the specific conductance of solutions of prehnitene and durene changed with time, and additional experiments indicated this was due to rearrangement toward isodurene. It should be noted that the symmetrical configuration 1,2,4,5- is the strongest base of the three tetramethylbenzenes. The concentration and stability of the ArH+ ions are the important factors in the isomerization. With the xylenes and trimethylbenzenes in anhydrous hydrofluoric acid, no reaction was observed at 20°, but isomerization did take place upon addition of boron trifluoride. This is interpreted to be due to an increase in the concentration of ArH+ by the reaction... 

Static leaching experiments were done in which the coal waste was shaken with deionized water for 1 to 50 days. The mixtures were then filtered and the filtrate was analyzed for acidity, specific conductance, and trace element content. All these measurements increased with leaching time. In many cases, the leachates were very acidic, with pH values less than 2, indicating that this waste could generate drainages of environmental concern. Iron, arsenic, nickel, manganese, and aluminium had concentrations in the waste effluents that are of... 

The weathering cycles consisted of weekly additions of water equivalent to 3/4 in. of rain, which was drained from each box 24 hours later and analyzed for pH, specific conductance, and iron species. Sample aliquots were acidified and retained for trace element analyses to be conducted after the completion of the experiment. The procedural details of this experiment are reported in Ref 5. 

Chance discoveries Sometimes, when a scientist plans research with a specific goal in mind, he or she will conduct experiments and reach a conclusion that is expected. Sometimes, however, the conclusion reached is far different from what was expected. Some truly wonderful discoveries in science have been made unexpectedly. 

Flip angles are determined by the specific 2D experiment being conducted, and Erast angle considerations are not an issue. The COSY family of experiments has a variety of final pulses (Section 6-1), and they are considered in Section 7-7a. Moreover, the final pulse before that is delivered to the detected nucleus is known as the read pulse,... 

---