Conductance time , reciprocal

Conductivity (electrical) n. The reciprocal of volume resistivity the conductance of a unit cube of material. The SI unit is siemens per meter (S/m). It is measured by the quantity of electricity transferred across unit area, per unit potential gradient per unit time. Reciprocal of resistivity. Volume conductivity or specific conductance, k = lip where p is the volume resistivity. Mass conductivity = kid where d is density. Equivalent conductivity A = kic where c is the number of equivalents per unit volume of solution. Molecular conductivity p = kim where m is the number of moles per unit... 

In the same section, we also see that the source of the appropriate analytic behavior of the wave function is outside its defining equation (the Schibdinger equation), and is in general the consequence of either some very basic consideration or of the way that experiments are conducted. The analytic behavior in question can be in the frequency or in the time domain and leads in either case to a Kramers-Kronig type of reciprocal relations. We propose that behind these relations there may be an equation of restriction, but while in the former case (where the variable is the frequency) the equation of resh iction expresses causality (no effect before cause), for the latter case (when the variable is the time), the restriction is in several instances the basic requirement of lower boundedness of energies in (no-relativistic) spectra [39,40]. In a previous work, it has been shown that analyticity plays further roles in these reciprocal relations, in that it ensures that time causality is not violated in the conjugate relations and that (ordinary) gauge invariance is observed [40]. 

A guarded hot-plate method, ASTM D1518, is used to measure the rate of heat transfer over time from a warm metal plate. The fabric is placed on the constant temperature plate and covered by a second metal plate. After the temperature of the second plate has been allowed to equiUbrate, the thermal transmittance is calculated based on the temperature difference between the two plates and the energy required to maintain the temperature of the bottom plate. The units for thermal transmittance are W/m -K. Thermal resistance is the reciprocal of thermal conductivity (or transmittance). Thermal resistance is often reported as a do value, defined as the insulation required to keep a resting person comfortable at 21°C with air movement of 0.1 m/s. Thermal resistance in m -K/W can be converted to do by multiplying by 0.1548 (121). 

Throughput is therefore proportional to mass flow rate. For a given mass now rate, throughput is independent of pressure. The relation between throughput and pressure drop Ap =pi—po across a flow element is written in terms of the conductance C. Resistance is the reciprocal of conduc tance. Conductance has dimensions of volume per time. 

Debye and Falkenhagen predicted that the ionic atmosphere would not be able to adopt an asymmetric configuration corresponding to a moving central ion if the ion were oscillating in response to an applied electrical field and if the frequency of the applied field were comparable to the reciprocal of the relaxation time of the ionic atmosphere. This was found to be the case at frequencies over 5 MHz where the molar conductivity approaches a value somewhat higher than A0. This increase of conductivity is caused by the disappearance of the time-of-relaxation effect, while the electrophoretic effect remains in full force. 

If initial solute uptake rate is determined from intestinal tissue incubated in drug solution, uptake must be normalized for intestinal tissue weight. Alternative capacity normalizations are required for vesicular or cellular uptake of solute (see Section VII). Cellular transport parameters can be defined either in terms of kinetic rate-time constants or in terms of concentration normalized flux [Eq. (5)]. Relationships between kinetic and transport descriptions can be made on the basis of information on solute transport distances. Note that division of Eq. (11) or (12) by transport distance defines a transport resistance of reciprocal permeability (conductance). 

Figure 2. Reciprocal conductance relaxation times as a function of the square root of TBAP concentration in media and concentration range where conductance indicates a preponderance of the simple ions. TBAP in diphenyl ether (D— 3,55) at 318 ( ). TBAP in benzene-chlorobenzene (60 40 v/v D = 3, 55) at 298 (A). TBAP in benzene-chlorobenzene (60 40 v/v D = 3, 64) at 298 and 350 atm (2). TBAP in benzene-chlorobenzene (60 40 v/v D = 3, 36) at 323 (0).

Considering these different limiting forms of the recombination term an Important tentative conclusion emerges the concentration dependence of the reciprocal relaxation time is a direct measure of the main ionic recombination process and yields therefore information on the ionic species present in solution. A linear dependence on total ion-pair concentration would therefore indicate unilateral triple ion formation or, if both kinds of triple ions are present as indicated by conductance, a sufficient difference in their stability. At this point it should be noted that the usual method of Fuoss and Draus... 

Figure 3. Dependence of the reciprocal conductance relaxation time on TBA— salt concentration in media and concentration range where conductance indicates an important fraction of triple ions. TBA-bromide in benzene-nitrobenzene (3, 22 vol % D = 2, 90) at 298 ( ). TBA-picrate in benzene-chlorobenzene (16 vol % D = 2, 78) at 298 (0).

As a second example we turn to the analysis of the conductance relaxation observed in tetrabutylammonlun plcrate in benzene-chlorobenzene over the concentration range 0.1—2 x 10 M as shown in Figure 3. A qualitative, but important difference with the previous example is the linear relation between reciprocal relaxation time and total TBAP-concentratlon. 

Since the uncertainty of the numerical values in K3 makes the test of eq. 4b somewhat hazardous, the temperature, and pressure, dependence of the conductance relaxation was investigated. Temperature, and pressure, dependence of intercept and slope of the experimental reciprocal relaxation time vs. concentration is given in Table III. If the reciprocal relaxation time indeed is functionally described by eq. 14 b then we are able to calculate these temperature, and pressure, dependences from previously obtained experimental data. 

The tinctura iodi of the British Pharmacopoeia is a soln. of half an ounce of iodine, and a quarter of an ounce of potassium iodide in a pint of rectified spirit. P. Wantig found the mol. ht. of soln. —1 941 Cals., and S. U. Pickering —1 714 per 880 mol. of ethyl alcohol. C. Lowig found that alcoholic tincture of bromine is slowly decomposed in darkness, rapidly in light. Alcoholic soln. of iodine, according to H. E. Barnard, are stable in light and in darkness, but according to J. M. Eder they decompose 1000 times more slowly than chlorine water under similar conditions T. Budde has shown that hydriodic acid, acetic ester, and aldehyde are formed, and the electrical conductivity of the soln. increases. J. H. Mathews and E. H. Archibald and W. A. Patrick found a freshly prepared AT-soln. to have an electrical conductivity of 2 4 XlO-6 reciprocal ohms and a sat. soln., 1 61 X10 4 reciprocal ohms at 25°. The decomposition is accelerated by the presence of platinum. The heat of soln. decreases with concentration from —7 92 to —7 42 cals, respectively for dilute and sat. soln. in methyl alcohol, and likewise from —4 88 to —5 22 cals, for similar soln. in ethyl alcohol. The solubility of iodine in aq. soln. of propyl alcohol is not very different from that in ethyl alcohol. 

Electrolytic resistivity tthe reciprocal of conductivity is similarly defined as the electrical resistance of a unit cuhe of solution, h is expressed in the same units as electrical resistivity, i.e.. ohms times u unit of length. Most commonly we find ohm-cin (J2-cml and ohm-meter (fi-m) ... 

Given the complex nature of many commercial work environments, as well as the reciprocal interactions between employers and employees, factors associated with the development and implementation of performance impairment test systems in commercial environments become equally complex. In addition to the selection of test systems that are reliable and valid indicators of performance impairment, it is equally important to consider issues associated with worker acceptance of the testing system, time associated with the test, and the economic implications of use and non-use of impairment test systems. Substantial research into the use of impairment testing systems has been conducted over the past decade however, the vast majority of this work is available only in company reports and/or technical monographs with few exceptions (e.g., Delta), little information is available in peer-reviewed scientific publications. 

On the other hand, conductivity (cr) or specific conductance (reciprocal of resistivity p) is a material property that is normalized with respect to area, potential gradient, and time. It is expressed as the ratio of current density j (A cm-2) and electric field E (V cm-1). 

Gardner and Widstoe (1921) made attempts to develop a general equation. They assumed an ideal soil to be one in which the capillary potential was a linear function of the reciprocal of the moisture-content (after Buckingham, 1907), and that the inherent moisture conductivity is independent of the moisture-content. These assumptions are necessary for mathematical reasons. For downward flow through sand, whose surface is kept saturated, the equation connecting the time t and distance from the surface L was as follows ... 

In Section 4, we have examined, from a fundamental point of view, how temperature and cure affect the dielectric properties of thermosetting resins. The principal conclusions of that study were (1) that conductivity (or its reciprocal, resistivity) is perhaps the most useful overall probe of cure state, (2) that dipolar relaxations are associated with the glass transition (i.e., with vitrification), (3) that correlations between viscosity and both resistivity and dipole relaxation time are expected early in cure, but will disappear as gelation is approached, and (4) that the relaxed permittivity follows chemical changes during cure but is cumbersome to use quantitatively. 

Resistivity. The reciprocal of conductivity the electric pressure required to secure unit flow of electric charge through a unit cube of the substance in unit time. 

Fig. 11.5 shows heat evolution curves, obtained by conduction calorimetry, for a CjS paste with and without addition of CaCU. When the latter is present, the main heat evolution peak begins earlier and rises and falls more steeply its maximum is reached earlier. The rate of heat evolution at the maximum is positively correlated with the reciprocal of the time at which the maximum occurs (D18). The linear relation extends to organic retarders. As these probably act by hindering the growth of C-S H (Section 11.2.2), this evidence suggests that the accelerators act by promoting it. 

The reciprocal of the specimen resistance in the equivalent parallel circuit for a given frequency is sometimes called the specimen conductance GP. It is a combination of DC conductance, by which we mean any real flow of charge through the sample under the influence of the applied field, and the anomalous conductance due to any time-dependent polarisation processes. The contribution that a true DC conductivity dielectric loss at an angular frequency w can be readily calculated as follows for the material in a parallel-plate capacitor. If the capacitor plates have area A and separation s ... 

Eventually there is a critical frequency above lO s at which the ionic cloud cannot adjust anymore to the ion s movements in the right way because there is too much inertia to execute the rapid changes required by the oscillating applied field. The reciprocal of this critical frequency is called the relaxation time of the asymmetry of the ionic cloud. As a consequence, an increase in conductivity occurs at this frequency because there is no longer more charge behind the ion than in front. This increase in conductance at the critical frequency is called the Debye effect. It is part of the evidence that shows that the ionic atmosphere is indeed present and functioning according to the way first calculated by Debye. 

Fig. 13. Hydration dependence of protonic conduction. The dielectric relaxation time, Ts, is shown versus hydration, h, for lysozyme powders. The relaxation time is proportional to the reciprocal of the conductivity. (A) H20-hydrated samples solid curve, lysozyme without substrate , lysozyme with equimolar (GlcNAc)< at pH 7.0 , with 3x molar (G1cNAc)4 at pH 6.5. The relaxation time is nearly constant between pH 5.0 and 7.0. (B) HjO-hydrated samples solid curve, lysozyme without substrate 9, lysozyme with equimolar (GlcNAcb at pH 7.0. From Careri etal. (1985). 

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