Condition expression duplication

Thus, a polyester sample (1-3 g, exactly weighed) is dissolved in 25 mL of a titrated solution of acetic anhydride in dry pyridine (10% mass). The solution is heated to reflux for 1 h. After cooling, 50 mL pyridine and 10 mL water are added. The excess acetic acid present in the resulting solution is titrated by aqueous potassium hydroxide (0.5 mol/L) using a potentiometric titrator. The determination must be carried out in duplicate and a blank titration must be performed under the same conditions. The mass of polyester and the concentration of reactants should be adjusted to ensure that at least a fourfold excess of acetic anhydride is used. The final result (OH content) is expressed in mmol OH/g polyester or as the hydroxyl number, defined as the number of milligrams of KOH required to neutralize the acetic acid consumed per gram of polyester. [Hydroxyl number = (number of mmol OH/g polyester) x 56.106.]... 

Fig. 11.2 Effect of HU on ET-1 release in the supernatant of the TrHBMEC (a) and EA hy 926 (b) cell cultures. Results of the quantitative assessment of ET-1 by Elisa, from at least four independent experiments in duplicates, are expressed in pg of ET-1 mb supernatant per 5x10s plated cells. Control basal culture conditions, HU cells treated with HU 250 mM during 48 h, Cyto cells treated with cytokines TNFa and IFNy at 100 U/mL 1 during 48 h, HU+cyto combination of HU and cytokines.

In routine tests of environmental samples, many repeat analyses of a sample aliquots are not possible. Therefore, the precision of the test required is measured by a scale known as relative percent difference (RPD). This is determined from the duplicate analysis performed under identical conditions on two aliquots of one of the samples in a batch. It is calculated by dividing the difference of test results by the average of test results and expressing as percent. Thus,... 

With the normalizing condition that Pi + P2 = Po, we have an expression with three independent parameters, which has the attractive feature that with appropriate choice of constants, we can duplicate upward curvature in semilogarithmic plots of data. 

Beer s law, as expressed in Equations 24-6 and 24-8, can be used in several ways. We can calculate molar absorptivities of species if the concentration is known, as shown in Example 24-3. We can use the measured value of absorbance to obtain concentration if absorptivity and path length are known. Absorptivities, however, are functions of such variables as solvent, solution composition, and temperature. Because of variations in absorptivity with conditions, it is never wise to depend on literature values for quantitative work. Hence, a standard solution of the analyte in the same solvent and at a similar temperature is used to obtain the absorptivity at the time of the analysis. Most often, we use a series of standard solutions of the analyte to construct a calibration curve, or working curve, of A versus c (see Chapter 26, Figure 23-6) or to obtain a linear regression equation (see Chapter 8). It may also be necessary to duplicate closely the overall composition of the analyte solution to compensate for matrix effects. Alternatively, the method of standard additions (see Sections 8C-3 and 26A-4) is used for the same purpose. 

Figure 2. CEC inhibition of [ HJtamsulosin binding in HEK 293 cells expressing tti-AR subtypes. Membranes from transfected cells were incubated with 1 pM CEC for 10 min at 37°C. Membranes were washed and binding of a 90% saturating concentration of pHjtamsulosin determined. Values are expressed as a % of specific binding in membranes pretreated under identical conditions in the absence of CEC, and are the mean + S.E.M. of 5 experiments performed in duplicate.

For the application of these membranes to the electrolytic production of chlorine-caustic, other performance characteristics in addition to membrane conductivity are of interest. The sodium ion transport number, in moles Na+ per Faraday of passed current, establishes the cathode current efficiency of the membrane cell. Also the water transport number, expressed as moles of water transported to the NaOH catholyte per Faraday, affects the concentration of caustic produced in the cell. Sodium ion and water transport numbers have been simultaneously determined for several Nafion membranes in concentrated NaCl and NaOH solution environments and elevated temperatures (30-32). Experiments were conducted at high membrane current densities (2-4 kA m 2) to duplicate industrial conditions. Results of some of these experiments are shown in Figure 8, in which sodium ion transport number is plotted vs NaOH catholyte concentration for 1100 EW, 1150 EW, and Nafion 295 membranes (30,31). For the first two membranes, tjja+ decreases with increasing NaOH concentration, as would be expected due to increasing electrolyte sorption into the polymer, it has been found that uptake of NaOH into these membranes does occur, but the relative amount of sorption remains relatively constant as solution concentration increases (23,33) Membrane water sorption decreases significantly over the same concentration range however, and so the ratio of sodium ion to water steadily increases. Mauritz and co-workers propose that a tunneling process of the form... 

The factor that is least controllable in the deduction of static and kinetic friction values from stick-slip experiments is the condition of the contacting surfaces. This explains why Brockley and Davis [20] in their study of the influence of the time of contact on were unable to obtain repeatable results, as shown in Fig. 8-15a. For each series of determinations made with a single placement of the rider on the track, the plot of against the time of quiescent contact shows satisfactory self-consistency. But when the experiment is repeated with a fresh placement of the rider on the track, a different curve is obtained, self-consistent but not a duplicate of the previous experiment. This was traced to the variability of the surface with location on the rubbing track. Furthermore, it was demonstrated that a model of time-dependent junction growth could be made to yield the following expression ... 

The biggest advantage of the conditional operator is not in simple examples, like that above, but in more complicated settings, in which it allows one to avoid duplication of complicated expressions. 

Since the expression being evaluated at each stage can be different from the previous one, it is possible to construct an incomplete If statement or one that duplicates conditions. As a result, the If-else construct should be applied with caution. As the IF ELSE architecture demonstrates, it is good... 

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