Adjusted reference temperature

The indexing temperature for the reference toughness curves is termed the adjusted reference temperature (ART). ART is the irradiated RTndt plus a margin to account for uncertainties and to provide regulatory... 

RTndt = adjusted reference temperature at the edge of the flaw = RTndtw... 

Current practice in the USA is to use the guidelines in NRC (1988) to define the adjusted reference temperature as ART = initial RT+ARTndt + margin. In this instance, a margin term is added to account for uncertainty in initial RT and ARTndt and obtain conservative upper bound values of the adjusted reference temperature.The conventional P-riimit curve that includes both the ASME Code margin of 2 on pressure and the adjusted reference defined in the regulatory guidelines (NRC, 1988) is expressed as ... 

Polanyi s theory is adequate in a large domain near the normal boiling temperature of the adsorbate, with p taken equal to the density of pz of the liquid. Thus the adjustable parameters were adjusted to give a common tangent for the two curves p vs. T and pi vs. T, at a reference temperature T0, which is the normal boiling temperature, or the triple point temperature for C02. The following equation was obtained (17) ... 

To connect these results to the dielectric relaxation in curing systems, it is useful to examine the post-cure data of Shito et al. 49 50) and of Blyakhman et al. 5I,52). Figure 25 shows the fit of Shito s data for xd (the reciprocal of fmax) to the WLF Equation for a series of DGEBA resins cured with a variety of anhydrides50). In this case, the data were fit to the universal WLF Equation, using the reference temperature as an adjustable parameter, which fell in the range 55-61 °C above Tg for the various samples. 

Fig. 42. EELS spectra of adsorbed HQ/BQ at Pt(lll). (a) HQ (1.0mM) (b) BQ (1.0mM) (c) HQ (500mM). Experimental conditions supporting electrolyte, lOmM KF adjusted to pH = 4 with HF electrode potential, 0.2 V vs. Ag/AgCl (1M KC1) reference temperature, 23 + 1°C beam energy, 4 eV beam current, 0.15 nA reflected beam was detected at the specular angle (62° from the surface normal). Reprinted from ref. 80.

DSG is similar to DTA except the actual differential heat flow is measured when the sample and reference temperature are equal. In DSG both the sample and reference are provided with individual heaters. If a temperature difference develops between the sample and reference because of exothermic or endothermic reactions in the sample, the power input is adjusted to remove this difference. Thus, the temperature of the sample holder is always kept the same as the reference. 

In practice the computerized data reduction procedure consists of the series of steps listed in Table I. For both multimodal resonant frequency data and constant frequency dynamic taken at several different frequencies, the correct value of the reference temperature (Tq) is that which reduces the scatter of the modulus and loss tangent data to fit a smooth curve. The initially assumed value of T0 is taken as the temperature corresponding to the loss tangent maximum or Tg. If this value of T0 does not give satisfactory superposition, the assumed value of T0 is adjusted to a slightly higher value and the procedure is repeated until a satisfactory superposition is achieved. Previous... 

Fig. lO.a The inset shows the postulated variation of the solubility parameter 8 caused by deuterium labeling (symbols and V correspond to labeled and nonlabeled copolymers, respectively) and due to the change in ethyl ethylene fraction x. The cumulative analysis, described in text, yields the absolute 8 value for deuterated dx (A) and protonated hx (V) copolymers as a function of x at a reference temperature Tref=100 °C determined interaction parameters (as in Fig. 9) allow us to determine two sets of differences AS adjusted here to fit independent PVT data [140,141] measured at 83 °C ( ) and at 121 °C (O). b The interaction parameter, yE/EE, arising from the microstructural difference contribution to the overall effective interaction parameter (hxj/dxpej) in Eq. (19) as a function of the average blend composition (xi+Xj)/2 at a reference temperature of 100 °C.%E/ee values are calculated (see text) from coexistence data ( points correspond to [91,143] and O symbols to [136]) for blend pairs, structurally identical but with swapped labeled component. X marks %e/ee yielded directly [134] for a blend with both components protonated. Solid line is the best fit to data... 

A discrepancy exists between the calculated product rates and the design product rates. A better match can be obtained by adjusting the reference component K-values, which would reflect an adjusted column temperature profile. 

Use a 50 ml sample or a portion diluted to 50 ml with distilled water. Adjust sample temperature to that used for the standard curve. Add 5 ml each of SPADNS solution and zirconyl-acid reagent or 10 ml acid-zirconyl-SPADNS reagent. Mix well and read absorbance first setting the reference point of the photometer as above. If the absorbance falls below the range of standard curve, repeat using a diluted sample. 

In the boiler problem, the stable reference environment (Table II) is taken as atmospheric air saturated with H20 at T0 = 298.15°K (77°F) and pQ = 101320 Pascals (14.696 psia) in equilibrium with several condensed phases (12). These values of Tg and pg were chosen because they are representative of yearly average air conditions for much of the contiguous United States and because no adjustments for temperature need to be made when applying tables of heats of formation, absolute entropies and free energies of formation. Saturated air was chosen so that liquid water at Tg,pg would be in complete equilibrium with the... 

In the differential-temperature loop, signals representing the sample and reference temperatures, as measured by the platinum-resistance thermometers, are fed to the differential-temperature amplifier via a comparator circuit, which determines whether the reference or the sample temperature is greater. The differential-temperature-amplifier output then adjusts the differential-power increment put into the reference and sample heaters in the direction and magnitude necessary to correct any temperature difference between them. A signal proportional to the differential power is also transmitted to the pen of a recorder, giving a curve of differential power versus time (temperature). The area under a peak, then, is directly proportional to the heat energy absorbed or liberated in the transition,... 

Contact thermometers of a maximum-minimum type are also manufactured these make contact both on exceeding an upper limit and on dropping below a lower limit. By means of a fine adjusting screw the temperatures may be set with an accuracy of 0.1 °C [23]. Temperature control may be arranged to follow a variable reference temperature by moving the thermometer contact with a synchronous motor. 

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