Enthalpy-entropy relationships in the fluid kinetics of aqueous electrolyte solutions containing only negatively hydrated ions

Because the validity of linear relationship between activation parameters derived from kinetic measurements is currently in doubt, a re-assessment has been made of work presented in earlier papers. It has now been found that the previously reported linear relationships are in fact non-linear, but this does not invalidate the earlier conclusion that negatively hydrated ions behave as simple structure-breakers in water. The treatment of kinetic data is discussed and suggestions are made for establishing relationships between activation parameters, whether these are linear or non-linear.     

Therapist attitudes as influenced by A-B therapist type, patient diagnosis, and social class.

Attempted to clarify a number of inconsistent and contradictory findings regarding interactions between patient diagnosis (schizophrenic vs. neurotic) and the A-B therapist variable. 37 psychiatric residents completed Kemp's version of the A-B scale. The 10 highest and 10 lowest scorers then rated 4 patient vignettes on likability, discomfort, interest in treating, and prognosis. Patient social class as well as diagnosis were systematically controlled. Results support some of the previous research on likability but provided no support for other A-B * Patient Type interactions. A number of main effects for diagnosis and social class indicate that, in general, residents of both types hold more favorable attitudes toward neurotic and middle-class patients than they do toward schizophrenic and lower-class patients. (23 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Equating student satisfaction measures

Colleges and universities conduct student satisfaction studies for many important policy making reasons. However the differences in instrumentation and the use of students' self-reported ratings of satisfaction makes such decisions sample-, instrument-, and institution-dependent. A common metric of student satisfaction would assist decision makers by providing a richness of information not typically obtained. The present study investigated the extent to which two nationally known instruments of student satisfaction could be scaled on the same quantitative metric. Pseudo-common item equating (Fisher, 1997) based on five link items of low and high endorsability enabled comparisons of "similar, but not identical items, from different instruments, calibrated on different samples" (p. 87). Results suggest that both instruments measured similar constructs and could be reasonably used to create a single, common metric. While samples used in the experiment were less than ideal, results clearly demonstrated the usefulness and reasonability of the pseudo-common item equating process.     

Transformation of the plant growth regulator daminozide (Alar) and structurally related compounds with CuII ions: oxidation versus hydrolysis

As part of a study of metal ion effects on chemical transformations of nitrogen-containing agrochemicals, conversion of daminozide to succinate via cleavage of the hydrazide C-N bond was examined in the presence and absence of divalent metal ions. No conversion was observed in metal ion-free solutions or in the presence of 1.0 mM NiII, ZnII, and PbII. CuII, in contrast, markedly increased rates of daminozide to succinate conversion. Halide ions (CI-, Br-) had no effect on daminozide conversion in the absence of metal ions but markedly increased conversion rates observed in the presence of CuII. The nitrogen-donor ligands ethylenediamine, N-(2-hydroxyethyl)ethylenediamine, and 1,4,7,10-tetraazacyclododecane decreased rates of CuII-facilitated conversion, while 1,5,9-triazacyclododecane actually increased rates of conversion. H NMR and UV spectroscopy provide evidence for the formation of 1:1 CuII-daminozide complexes. Halide ion effects and nitrogen-donor ligand effects point to an oxidative mechanism for CuII-facilitated daminozide breakdown, rather than hydrolysis. The structurally related compound butyric acid 2,2-dimethylhydrazide (BH) is subject to the same CuII-facilitated breakdown via an oxidative mechanism. N,N-Dimethylsuccinamic acid (SA), in contrast, breaks down via a hydrolytic mechanism.     

The Effect of Silane Coupling Agents on the Durability of Titanium Alloy Joints

An aqueous solution of γ-glycidoxypropyltrimethoxysilane (GPS) applied to titanium alloy adherends greatly improved bond durabilities compared to alloy surfaces that were only abraded and solvent cleaned, γ-aminopropyltriethoxysilane (APS) also gave improved durability but was not so effective.

Three epoxy adhesives differed considerably in their responses to the five metal pretreatments that were compared. Overall, a sodium hydroxide anodise treatment gave the highest resistance to crack growth in the wedge test.     

Inverter-fed drives: which motor stators are at risk?

This article describes measurements of the surge voltage characteristics from a number of motors driven by inverter-fed drives (IFDs). The measurements were done with both laboratory and purpose-built instrumentation. Further, we discuss why certain surges deteriorate the insulation, and we give guidelines for determining which motors may be at risk of failure from IFD voltage surges. The effect of these surges on stator windings is also included, as well as means to determine if a motor installed in a severe surge environment will fail