Simultaneous measurement change

Ideally, one would like to know the number or proportion of voucher recipients whom the scheme protects from becoming impoverished or the reduction in income inequalities in health outcomes. This is known as poverty impact analysis. In practice, these outcomes can be very difficult to measure because of the need to simultaneously measure changes in the health status of subgroups within a population as well as within the population as a whole and to demonstrate that differences among subgroups were caused by the program. 

Fig. 11.10.11 / Potential oscillations and 2 the simultaneously measured changes of the EQCM frequency response, i.e., the variation of the surface mass, in the course of gedvanostadc electrooxidation of formic acid at a platinized Pt electrode (A = 0.3 cm ). = 10 MHz, I = 0.45 mA. Solution 0.5 mol dm HCOOH + 1 mol dm HOGa...

In this work, a microwave interferometric method and apparatus for vibration measurements is described. The principle of operation is based on measurement of the phase of reflected electromagnetic wave changing due to vibration. The most important features of the method are as follows simultaneous measurement of tlie magnitude and frequency of the rotating object high measurement accuracy weak influence of the roll diameter, shape and distance to the object under test. Besides, tlie reflecting surface can be either metallic or non-metallic. Some technical characteristics are given. 

The effects of adsorbed inhibitors on the individual electrode reactions of corrosion may be determined from the effects on the anodic and cathodic polarisation curves of the corroding metaP . A displacement of the polarisation curve without a change in the Tafel slope in the presence of the inhibitor indicates that the adsorbed inhibitor acts by blocking active sites so that reaction cannot occur, rather than by affecting the mechanism of the reaction. An increase in the Tafel slope of the polarisation curve due to the inhibitor indicates that the inhibitor acts by affecting the mechanism of the reaction. However, the determination of the Tafel slope will often require the metal to be polarised under conditions of current density and potential which are far removed from those of normal corrosion. This may result in differences in the adsorption and mechanistic effects of inhibitors at polarised metals compared to naturally corroding metals . Thus the interpretation of the effects of inhibitors at the corrosion potential from applied current-potential polarisation curves, as usually measured, may not be conclusive. This difficulty can be overcome in part by the use of rapid polarisation methods . A better procedure is the determination of true polarisation curves near the corrosion potential by simultaneous measurements of applied current, corrosion rate (equivalent to the true anodic current) and potential. However, this method is rather laborious and has been little used. 

As pointed out above, accumulatory pressure and weight loss measurements usually refer to the total reaction. When there are several volatile products, it is necessary to identify all components and investigate progressive changes in gas composition. Quantitative determinations of the amounts of each product (EGA) should, ideally, be combined with measurements of the total extent of reaction, although Gam [143] has recommended caution in the interpretation of results from simultaneous measurements. 

The electrochemical quartz crystal microbalance (EQCM) is a powerful tool for elucidating interfacial reactions based on the simultaneous measurement of electrochemical parameters and mass changes at electrode surfaces. The microbalance is based on a quartz crystal wafer, which is sandwiched between two electrodes, used to induce an electric field (Figure 2-20). The field produces a mechanical oscillation... 

Such approximation is valid when the thickness of the polymeric layer is small compared to die thickness of die crystal, and the measured frequency change is small with respect to the resonant frequency of the unloaded crystal. Mass changes up to 0.05% of die crystal mass commonly meet this approximation. In die absence of molecular specificity, EQCM cannot be used for molecular-level characterization of surfaces. Electrochemical quartz crystal microbalance devices also hold promise for the task of affinity-based chemical sensing, as they allow simultaneous measurements of both tile mass and die current. The principles and capabilities of EQCM have been reviewed (67,68). The combination of EQCM widi scanning electrochemical microscopy has also been reported recently for studying die dissolution and etching of various thin films (69). The recent development of a multichannel quartz crystal microbalance (70), based on arrays of resonators, should further enhance die scope and power of EQCM. 

Simultaneous weight-change and diamagnetic-anisotropy measurements upon adsorption and desorption of bromine in PG have been carried out (M4). They showed that final susceptibility values are reached well before full bromine saturations, and remain until 80% desorption is attained. 

FIG. 32 Top Semilog plot of the time constant t for ionic motion as a function of RH for KF. Bottom Simultaneously measured contact potential. At a critical humidity A, there is a break or a change in slope in these two surface properties. Below A, water solvates preferentially cations at the step edges. Above A, the rates of dissolution (solvation) of anions and cations are similar and water uni-... 

Sonication of 0.05 M Hg2(N03)2 solution for 10,20 and 30 min and the simultaneous measurements of conductivity, temperature change and turbidity (Table 9.2) indicated a rise in the turbidity due to the formation of an insoluble precipitate. This could probably be due to the formation of Hg2(OH)2, as a consequence of hydrolysis, along with Hg free radical and Hg° particles which could be responsible for increase in the turbidity after sonication. The turbidity increased further with time. Mobility of NO3 ions was more or less restricted due to resonance in this ion, which helped, in the smooth and uniform distribution of charge density over NO3 ion surface. Hence the contribution of NOJ ion towards the electrical conductance was perhaps much too less than the conduction of cationic species with which it was associated in the molecular (compound) form. Since in case of Hg2(N03)2, Hg2(OH)2 species were being formed which also destroyed the cationic nature of Hg22+, therefore a decrease in the electrical conductance of solution could be predicted. The simultaneous passivity of its anionic part did not increase the conductivity due to rise in temperature as anticipated and could be seen through the Table 9.2. These observations could now be summarized in reaction steps as under ... 

Summarizing, we stress that the anisotropy and the fluorescence decay functions change in a complex way as a function of target concentration. Species that fluoresce more intensely contribute disproportionably stronger to the measured parameters. Simultaneous measurements of steady-state intensities allow accounting this effect. 

Figure 3 is an example of simultaneous measurements of radon concentration in indoor air. The measurements shown in this figure were made under changing condition the indoor radon concentration increased after the room had been closed tightly. 

The first application of the quartz crystal microbalance in electrochemistry came with the work of Bruckenstein and Shay (1985) who proved that the Sauerbrey equation could still be applied to a quartz wafer one side of which was covered with electrolyte. Although they were able to establish that an electrolyte layer several hundred angstroms thick moved essentially with the quartz surface, they also showed that the thickness of this layer remained constant with potential so any change in frequency could be attributed to surface film formation. The authors showed that it was possible to take simultaneous measurements of the in situ frequency change accompanying electrolysis at a working electrode (comprising one of the electrical contacts to the crystal) as a function of the applied potential or current. They coined the acronym EQCM (electrochemical quartz crystal microbalance) for the technique. 

Shmigol AV, Eisner DA, Wray S 2001 Simultaneous measurements of changes in sarcoplasmic reticulum and cytosolic [Ca2+] in rat uterine smooth muscle cells. J Physiol 531 707-713... 

Very easy to change samples and sample holders and to carry out other operations simple compatibility with other apparatus for simultaneous measurements convection goes the natural way, no additional shielding is required for protection of the balance against radiation from the furnace. The other two arrangements 15 B and 15 C which are used besides the first variant are equal in the distribution of use. The advantages of variant C are similar to that of A ... 

Metabonomics has changed the way data are analyzed. Instead of the single biomarker concept, the goal is to simultaneously measure the entire range of plasma metabolites to see changes in the patterns of the biomarkers. This requires both analytical platforms that can assess the broad range of metabolites in an individual and the knowledge of metabolism that is necessary to interpret the analytical data. 

The third block in Fig. 2.1 shows the various possible sensing modes. The basic operation mode of a micromachined metal-oxide sensor is the measurement of the resistance or impedance [69] of the sensitive layer at constant temperature. A well-known problem of metal-oxide-based sensors is their lack of selectivity. Additional information on the interaction of analyte and sensitive layer may lead to better gas discrimination. Micromachined sensors exhibit a low thermal time constant, which can be used to advantage by applying temperature-modulation techniques. The gas/oxide interaction characteristics and dynamics are observable in the measured sensor resistance. Various temperature modulation methods have been explored. The first method relies on a train of rectangular temperature pulses at variable temperature step heights [70-72]. This method was further developed to find optimized modulation curves [73]. Sinusoidal temperature modulation also has been applied, and the data were evaluated by Fourier transformation [75]. Another idea included the simultaneous measurement of the resistive and calorimetric microhotplate response by additionally monitoring the change in the heater resistance upon gas exposure [74-76]. 

T. Takada. Temperature drop of semiconductor gas sensor when exposed to reducing gases - simultaneous measurement of changes in sensor temperature and in resistance . Sensors and Actuators B66 (2000), 1-3. 

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