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Calorimetry measurements

The SIMULAR, developed by Hazard Evaluation Laboratory Ltd., is a chemical reactor control and data acquisition system. It can also perform calorimetry measurements and be employed to investigate chemical reaction and unit operations such as mixing, blending, crystallization, and distillation. Ligure 12-24 shows a schematic detail of the SIMULAR, and Ligure 12-25 illustrates the SIMULAR reaction calorimeter with computer controlled solids addition. [Pg.946]

Polyetherimides show no crystallinity as evidenced from calorimetry measurements. The heteroarylene like phenylquinoxaline [27], oxadiazole [30], and benzoxa-zole [56] activated polyethers show TgS from DSC thermograms, with no evidence of crystallization, indicating amorphous or glassy morphology. Furthermore, wide angle x-ray scattering measurements show no evidence of crystalline or liquid crystalline type morphologies, consistent with an amorphous structure. F polyether... [Pg.54]

Differential scanning calorimetry measurements have shown a marked cooling/heat-ing cycle hysteresis and that water entrapped in AOT-reversed micelles is only partially freezable. Moreover, the freezable fraction displays strong supercooling behavior as an effect of the very small size of the aqueous micellar core. The nonfreezable water fraction has been recognized as the water located at the water/surfactant interface engaged in solvation of the surfactant head groups [97,98]. [Pg.482]

Isoperibolic calorimetry measurements on the n-butanol/water and n-butoxyethanol/water systems have demonstrated the accuracy and convenience of this technique for measuring consolute phase compositions in amphiphile/water systems. Additional advantages of calorimetry over conventional phase diagram methods are that (1) calorimetry yields other useful thermodynamic parameters, such as excess enthalpies (2) calorimetry can be used for dark and opaque samples and (3) calorimetry does not depend on the bulk separation of conjugate fluids. Together, the present study and studies in the literature encompass all of the classes of compounds of the amphiphile/CO ydrocarbon/water systems that are encountered in... [Pg.304]

For the [Fe(bpp)2]2+ system, spin transition behaviour is also observed in acetone solution. For the three salts examined, the tetrafluoroborate, iodide and hexafluorophosphate, the behaviour is virtually independent of the associated anion, unlike the situation in solid samples, and in this instance the molecular process occurs essentially independently of cooperative effects [86]. Analysis of the systems in terms of a simple low spin high spin thermal equilibrium gives AH=20 1 kj mol-1 and AS=80 4 J K-1 mol-1 for the forward process, values typical for iron(II) spin crossover systems and similar to those obtained for solid [Fe 592][BF4]2 (AH=24 kj mol-1 and AS=100 J K-1 mol-1) from differential scannning calorimetry measurements [94],... [Pg.95]

TGA analysis shows that polymer degradation starts at about 235°C which corresponds to the temperature of decomposition of the cellobiose monomer (m.p. 239°C with decom.). Torsion Braid analysis and differential scanning calorimetry measurements show that this polymer is very rigid and does not exhibit any transition in the range of -100 to +250 C, e.g. the polymer decomposition occurs below any transition temperature. This result is expected since both of the monomers, cellobiose and MDI, have rigid molecules and because cellobiose units of the polymer form intermolecular hydrogen bondings. Cellobiose polyurethanes based on aliphatic diisocyanates, e.g. HMDI, are expected to be more flexible. [Pg.191]

The data obtained directly from adsorption calorimetry measurements can be expressed in different ways (Figure 13.5 [155]) as follows ... [Pg.216]

FIGURE 13.5 Calorimetric and volumetric data obtained from adsorption calorimetry measurements Raw pressure and heat flow data obtained for each dose of probe molecule and Thermokinetic parameter (a), Volumetric isotherms (b), Calorimetric isotherms (c), Integral heats (d), Differential heats (e), Site Energy Distribution Spectrum (f). (From Damjanovic, Lj. and Auroux, A., Handbook of Thermal Analysis and Calorimetry, Further Advances, Techniques and Applications, Elsevier, Amsterdam, 387-438, 2007. With permission.)... [Pg.217]

Peak temperatures (°C) determined by differential scanning calorimetry measurements on heating... [Pg.398]

NdOs4Sbi2 may undergo a displacive-type phase transition at -86 °C in which the Nd atoms freeze at off center positions (Evers et al., 1995). This transition was proposed on the basis of scanning calorimetry measurements and the huge room temperature value for the Nd atomic displacement parameter (Beq = 4 A2). [Pg.23]

S. van Herwaarden. Calorimetry measurement. In J.C. Webster, editor, Measurement, Instmmentation, and Sensors Handbook, 2nd Edition, Chap. 36. CRC Press, Boca Raton, 1999. [Pg.38]

This work was principally supported by a grant from the General Electric Co. The studies also were partly supported by grant DMR75-05004 from the National Science Foundation, grants from the Army Research Office and from the Materials Research Laboratory of the University of Massachusetts. One of us (A.E.) appreciates the travel support from the International Commission for Cultural Exchange between the United States and Spain. We would like to express also our appreciation to E. Balizer who obtained the calorimetry measurements. [Pg.477]

Kowalski, B., Gruczynska, E., and Maciaszek, K. 2000. Kinetics of Rapeseed Oil Oxidation by Pressure Differential Scanning Calorimetry Measurements. Ear. I Lipid Sci. Technol., 102, 337-341. [Pg.52]

Differential scanning calorimetry measures heat flow as a function of temperature. When starch is heated in the presence of excess water, a sharp peak (an endotherm) is obtained, which is caused by the disordering of... [Pg.167]

Fig. 6.24. Differential scanning calorimetry measurements of the heat released during equilibration of n-type a-Si H after (a) fast and b) slow cooling (Matsuo et al. 1988). Fig. 6.24. Differential scanning calorimetry measurements of the heat released during equilibration of n-type a-Si H after (a) fast and b) slow cooling (Matsuo et al. 1988).
Differential scanning calorimetry measures the thermodynamic parameters associated with thermally induced phase transitions. Here, the sample of interest and an inert reference are heated or cooled independently at a programmed rate, and in tandem, such that their temperatures change in unison and the differential temperature is maintained at zero. If the sample undergoes a thermally induced transition, heat must be applied to or withdrawn from the sample in order to maintain the same temperature in both sample and reference compartments. The instrument measures the heat flow into the sample relative to the reference and this dijferential heat flow (or excess specific heat) is recorded as a function of temperature, resulting in a trace, as shown in Fig. 1... [Pg.92]


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See also in sourсe #XX -- [ Pg.311 , Pg.331 , Pg.332 , Pg.333 , Pg.334 , Pg.335 , Pg.336 , Pg.337 ]




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