Compensation technique

Any deviation from the above criteria is indicative of kinetic complications and should be treated individually. However, one case is worthy of note. In non-aqueous solutions, it is commonly observed that AEP, for example, has typical values between 70 and 100 mV owing to the so-called IR drop resulting from the uncompensated and relatively large solution resistance. While IR compensation techniques are available, they are not always reliable, and it is more convenient to compare the measured AEP with that of a known reversible reaction measured under similar conditions. 

The data for the compensated CT-VPP-REDOR curves exhibits a similar trend, a decrease of the M2 values with increasing value for the dipolar evolution time (cf. Table 1). For the compensated CT-VPP-REDOR approach, however, the data for short evolution times (N=2) produces an M2 value slightly higher than the theoretical value, whereas the data for N=8 entails an M2 value smaller than the theoretical value. Thus, the compensation technique tends to overcompensate the experimental imperfections at low evolution times, whereas it leads to an undercompensation at longer evolution times. This behaviour may be the... 

The potentiality of the classical method treated here for the study of fast charge transfer reactions can be estimated as follows. Using a refined capacitive current compensation technique, Bos and van Dalen [30] were able to achieve transition times down to 0.1 s. In view of Fig. 6, non-reversibility is detected if — j/(nFcoksh) > 0.15, i.e. ksh < 6x -H nFc 0) = 6(7tD0)1/22t1/2 3 x 10 2 eras 1. 

The analytical predictor, as well as the other dead-time compensation techniques, requires a mathematical model of the process for implementation. The block diagram of the analytical predictor control strategy, applied to the problem of conversion control in an emulsion polymerization, is illustrated in Figure 2(a). In this application, the current measured values of monomer conversion and initiator feed rate are input into the mathematical model which then calculates the value of conversion T units of time in the future assuming no changes in initiator flow or reactor conditions occur during this time. 

The calorimetric technique used in the titration experiment illustrated in Figure 9 allows short time intervals between the injections due to a comparatively low time constant for the instrument in combination with the electrical compensation technique. Rather, slow heat conduction microcalorimeters can be used in fast titration experiments if a dynamic correction, based on the Tian equation (equation (17)), is employed (Bastos et al., 1991 Backman et al., 1994). 

Photon shot-noise or preamplifier shot-noise limitations, or source-flicker-noise limitations but utilizing source compensation" techniques... 

Fig. 10. Diagram aiding in the explanation of the Babinet compensator technique of measuring birefringence...

Fig. 19. Plot of birefringence as measured by the compensator technique against the orientation function as measured by the sonic method. Values in parenthesis represent theoretical values for Nylon 66, cellulose, and polypropylene from top to bottom respectively...

Both the sensitivity and the offset of the bridge are functions of temperature (Fig. 6.2.2). The temperature coefficient of sensitivity (TCS) is always negative and relatively constant (typically -0.2%/K). The bridge offset creates the largest part of the temperature coefficient of the bridge offset (TCO) and is caused by the TCS compensation technique used. 

The correctness of Natta s view was shown by Veerkamp and Veer-mans (92) who determined the intensities of the absorptions occurring in C2-C3 copolymers at 13.64 and 13.85 p by using an optical compensation technique from the resulting data they derived the distribution of the CH2 groups over sequences of 3 and 5 or more CH2 groups as a function of C3 incorporation. 

When a well-located control temperature is excessively sensitive to pressure changes, pressure compensation is often added. The most common pressure compensation technique is differential temperature control (see Sec. 18.8). Alternatively, a control temperature can be linearly compensated for pressure changes. 

The linear compensation technique calculates a compensated temperature Tc (°F) using the measured temperature, T (°F), the measured pressure, P (psia), and a compensation reference pressure,... 

Figure 6.6 shows an example for Fe in O.OIN HCl/EtOH with and without IR-drop compensation. Without IR-drop compensation, a straight line is observed over the entire range of polarization. When the IR-drop is compensated, curvature is seen and the shape of the curve indicates that. Without compensation of the ohmic drop Rp was 357 ohms. c5n applying a compensation technique Rp was found to be 74 ohms, R, being 212 ohms. 

Some of the more expensive commercially available potentiostats are, or can be, equipped vnth these forms of ohmic drop compensation technique. In principle, the method can be applied when the values of and the measuring resistance change during the measurements. 

In solids there are two general methods used for the determination of An. One is the transmission method while the other is a compensator technique. Each has advantages and disadvantages and thus the method chosen depends highly on the experimental circumstances as well as on the material itself. It is worth pointing out that the above discussion applies to both uniaxially and biaxially oriented systems. Two other methods not to be discussed here are interference microscopy and refractometry. ... 

For analytical purposes it is essential that interference effects in atomic absorption spectroscopy be eliminated or minimized. If they cannot be eliminated, it is necessary to compensate adequately for their presence through use of proper standards or other compensating techniques. This section deals with this problem. Reference also should be made to Chapter 9, as many techniques used for flame emission also apply to atomic absorption. 

C.Carrison, B.Krzyzabiwsju, N.Foss Non-Uniformity Compensation Techniques for Staring IR Focal Planes , Proc. SPIE Tech. Symp. East "79, Washington, D.C., April, 1979... 

Piezoelectric Materials Temperature and Stress Compensation Techniques and Aging Effects... 

The resonant frequency of the crystal depends on the physical properties and dimensions of the crystal. For applications requiring precision frequency control these properties and dimensions must be very stable. When stability is an issue, compensation techniques may be required to achieve the desired frequency control. Crystal resonators are typically plates with finite dimensions. The mechanical resonant frequencies for these bounded crystal plates are not easy to obtain thro ugh exact calculation. For circular and rectangular plates three-dimensional vibrations are possible, but they are difficult to model exactly. Approximations, however, are used to describe the complex modes of vibration in these systems. Methods for employing these approximations are discussed in detail in Zelenka (1986). 

In the days of linear, continuous electronics non-linearity was a major problem. Such compensation techniques as were available were based on diode networks having reciprocal characteristics, but by their nature these were relatively crude. As a result all non-linear primary sensor mechanisms tended to be ignored. Now, linearisation processes such as look-up tables or polynomials are easily realisable with digital electronics. 

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