Infra-red investigations on the hydrocarbon cyperene-II

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Effect of Ca-Montmorilionite Expansion on X-ray Diffraction lntensities

The most abundant clay mineral group in Iowa soils is montmorillonite, most commonly calcium-saturated (Hanway et al. 1960). The calcium montmorillonite-water system was therefore selected for detailed X-ray study. Montmorillonite is unusual among minerals in that it has an expansible lattice in the c direction. That is, upon wetting with water, the individual silicate layers separate to allow entry of water, and the mineral expands. Characteristics of expansion are readily studied by means of X-ray diffraction: the X-ray diffraction angle gives the average layer-to-layer d001 spacing for any given moisture condition; the sharpness of the diffraction peak is a measure of uniformity of the d001 spacing; and the intensity of the peak relates to uniformity of the d001 spacing and in addition to the electron density distribution within the repeating elements. The latter is embodied in the structure factor . The variation of d001 structure factor caused by montmorillonite expansion is the subject of this paper

Mother's social cognitions and discipline responses Differences between physical and relational aggression

This research was designed to explore differences in mothers' social cognitions, affect, and proposed discipline responses to physical and relational aggression. The two main aims of the research were: (1) to examine whether maternal social cognitions (i.e. attributions of responsibility and stability, and descriptive norms) about, and their responses to, children's aggressive behavior vary as a function of aggression form; and (2) to investigate the associations between mothers' social cognitions and their emotional reactions and proposed discipline responses (i.e., level of power assertion). Ninety-nine mothers of 3rd-5th grade students read hypothetical vignettes depicting their child engaged in relational and physical aggression. Following each story, mothers responded to nine questions that assessed social cognitions, affect, and discipline responses. Overall, the results indicated that mothers hold a different set of cognitions about relational aggression as compared to physical aggression, and that these cognitions are reliably linked to their proposed responses to children. Specifically, in situations depicting relational aggression as compared to physical aggression, mothers viewed the behavior as more normative, and they attributed less responsibility to children for engaging in the behavior. Mothers also reported that they would experience less negative affect and employ lower levels of power assertion in relational aggression situations. Implications of these findings for models of parental influence on child peer competence and for parent education are discussed

Fourier Transform Infrared Thermal Analysis of a Segmented Polyurethane

Fourier transform infrared spectroscopy (FTIR) has been used to study the extent of hydrogen bonding and its temperature dependence in a segmented polyurethane elastomer synthesized from 2,6-toluene diisocyanate, 1,4-butanediol, and poly(tetramethylene oxide) of 2060 number average molecular weight. It is found that the ratio of the molar extinction coefficient for the hydrogen bonded to the free amine stretching vibration is 4.6 and that this ratio is 1.05 for the hydrogen bonded to the free carbonyl stretching vibration. The temperature dependence of the concentration of hydrogen bonded groups is without any discontinuity at the hard segment glass transition temperature, and the enthalpy and entropy of hydrogen bond dissociation are 29 kJ moJ^(- 1) and 64 J mo1^(-1) K^(-1), respectively. An additional absorption band in the carbonyl stretching region at 1726 cm-1 is attributed to an oxidation product of the polyether segment formed during initial sample preparation and subsequent thermal treatment