Crystallization Fouling Of The Aqueous Two-Component System CaSO\u3csub\u3e4\u3c/sub\u3e/CaCO\u3csub\u3e3\u3c/sub\u3e

Solutions, which cause fouling problems, consist mostly of more than one single component. Up to now only few studies concerning the fouling phenomena in such multicomponent systems exist. Therefore batch and continuous experiments with the aqueous two-component system CaSO4/CaCO3 were carried out, investigating especially the influence of pH-value on the fouling behaviour. As measure for the crystalline deposit the fouling resistance Rf was used. The composition of the obtained fouling layers were analysed by x-ray diffraction and scanning electron microscopy (SEM). Further the strength of the crystalline deposits were determined in abrasion experiments. The measured abrasion was correlated with crushing strength values. In the fouling experiments a strong effect of the pH-value on crystallization fouling was observed. Lowest fouling tendency was seen for experiments at pH 7.0. At different pH-values the crystalline layers showed big differences in their macroscopic as well as in their microscopic structure. As it could be seen with the SEM the crystals differed in their size but also in their shape. Below pH 6.0 only calcium sulphate was detected by x-ray diffraction, which agrees with the saturation theory. At higher pH values besides calcium sulphate also calcium carbonate was found in different modifications. The different layer composition leads to different strength of the layers. Highest strength values in the crystalline upper and middle layer were measured for crystalline scales grown at pH 7.0, followed by layers at pH 6.5. At the moment it is difficult to correlate the fouling behaviour clearly to the different experimental conditions

The role of treatment delivery factors in exposure-based cognitive behavioral therapy for panic disorder with agoraphobia

Treatment delivery factors (i.e., therapist adherence, therapist competence, and therapeutic alliance) are considered to be important for cognitive behavioral therapy (CBT) for panic disorder and agoraphobia (PD/AG). In the current study, four independent raters conducted process evaluations based on 168 two-hour videotapes of 84 patients with PD/AG treated with exposure-based CBT. Two raters evaluated patients' interpersonal behavior in Session 1. Two raters evaluated treatment delivery factors in Session 6, in which therapists provided the rationale for conducting exposure exercises. At the 6-month follow-up, therapists' adherence (r=0.54) and therapeutic alliance (r=0.31) were significant predictors of changes in agoraphobic avoidance behavior; therapist competence was not associated with treatment outcomes. Patients' interpersonal behavior in Session 1 was a significant predictor of the therapeutic alliance in Session 6 (r=0.17). The findings demonstrate that treatment delivery factors, particularly therapist adherence, are relevant to the long-term success of CBT for PD/AG