Stress Heterogeneity Effect on the Strength of Silicon Nitride

The experiments reported in this paper demonstrate the causes of the failure of monolithic ceramics. The specimens are made of silicon nitride and tested at room temperature. The stress field within the specimen is different for each of four series of tests that have been conducted. Fractographic observations have also been made to identify the causes of the failures. A size effect analysis is performed.     

Alpha olefin sulfonates from a commercial SO3-Air reactor

Alpha olefin sulfonate (AOS) can be made by SO₃-air sulfonation of straight chain alpha olefins followed by saponification of the neutralized product. The sulfonation step forms unsaturated sulfonic acids, sultones and sultone sulfonic acids. Hydrolysis of the various sultones yields a mixture of unsaturated and hydroxy sulfonates. Sulfonation of commercial mixtures of straight chain alpha olefins in a large-scale SO₃ falling film unit has given AOS of 1.5–3.0% oil based on active content and tristimulus color of about 40% saturation (2% solution) which is readily bleachable with 1–3% NaOCl to about 10–15% saturation. Performance of AOS made from C₁₅−C₁₈ alpha olefin is comparable to that of the high-foaming C₁₁−C₁₄ LAS in both detergency and dishwashing foam. It is superior to similar products made from internal straight chain olefins. The product shows a low order of toxicity and biodegrad-ability slightly better than that of LAS. A C₁₅−C₁₆ AOS blend is especially attractive in liquid detergent formulations. Presented at the AOCS Meeting, Los Angeles, April 1966.     

Improving the heat transfer of nanofluids and nanolubricants with carbon nanotubes

Low thermal conductivity is a primary limitation in the development of energyefficient heat transfer fluids required in many industrial and commercial applications. To overcome this limitation, a new class of heat transfer fluids was developed by suspending nanoparticles and carbon nanotubes in these fluids. The resulting heat transfer nanofluids and nanolubricants possess significantly higher thermal conductivity compared to unfilled liquids. Three types of heat transfer nanofluids and nanolubricants, each containing controlled fractions of single-wall carbon nanotubes, multiwall carbon nanotubes, vapor grown carbon fibers, and amorphous carbon have been developed for multifunctional applications, based on their enhanced heat transfer and lubricity properties. For more information, contact F.D.S. Marquis, South Dakota School of Mines and Technology, Department of Materials and Metallurgical Engineering, Rapid City, SD 57701; (605) 394-1283; fax (605) 394-3369; e-mail fernand.marquis@sdsmt.edu.     

Michael J. Mahoney: A retrospective.

Michael Mahoney, who made seminal contributions not only to the Society for the Exploration of Psychotherapy Integration (SEPI) but also to the entire field of psychotherapy, died a tragic death at the age of 60 on May 31, 2006. He published more than 250 scholarly articles and chapters, authored and edited 19 books (one of which was awarded a Citation Classic by the Science Citation Index), edited 4 journals, and served on 23 editorial boards plus numerous guest editorships and advisory boards. His research spanned a tremendous breadth without sacrificing depth. Primarily, however, he inquired into development across the life course, including but not limited to psychotherapy. Initially trained as a behaviorist, he played a significant role in the cognitive revolution in psychology; he was also a leading figure in constructivist psychotherapies. He was a Fellow of the World Academy of Art and Science, as well as a Fellow of the American Association for the Advancement of Science. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Shear decohesion of clamped abraded steel interfaces reinforced with epoxy adhesive

This paper presents an experimental assessment of quasi-static shear strength of the combined mechanically clamped and epoxy adhesive reinforced steel interfaces. The effect of the surface roughness and clamping load on the combined interfacial decohesion and slipping is investigated. The maximum shear strength of the adhesive reinforced specimens with fine ground, coarse ground and grit blasted contact surface finishes is reported with comparison to the results of the identical non-reinforced specimens. Results have been assessed both in terms of calculated fracture energy and interface decohesion. The bonded interfaces with grit blasted finish showed considerably higher maximum shear stresses as compared to the identical ground cases. The shear strength contributions of strong clamping and reinforcing conformed well to the principle of superposition for all experimented interface types.     

THREE-DIMENSIONAL NUMERICAL MODELING OF HEAT AND MASS TRANSFER IN A CERAMIC OXYGEN GENERATOR (COG)

A three-dimensional numerical model has been developed to simulate the conjugate heat transfer and the separation of oxygen from air in a single-cell ceramic oxygen generator (COG). Attention is focussed on the temperature distribution in the brittle ceramic electrolyte as a result of heat generated from electrochemical reactions and the resistance to current flow. Investigations conducted to determine the influence on the thermal behaviour of the electrolyte with the presence of metallic current collectors and gas distributors in the model will also be summarised.     

Characterization of aqueous and solid inclusion complexes of diuron and isoproturon with beta-cyclodextrin

The interaction of diuron and isoproturon herbicides with beta-cyclodextrin is conducive to the formation of inclusion compounds in aqueous solution as well as in the solid state. The physico-chemical study of these complexes was carried out by various analytical techniques such as ultraviolet (UV), Fourier transform infrared (FT-IR), Raman, X-ray diffraction, and 1H-NMR (nuclear magnetic resonance) spectroscopies. The existence of inclusion complexes in water solution between the beta-cyclodextrin and each of the herbicides was revealed by electronic absorption and 1H-NMR spectroscopies. A 1:1 stoichiometry was determined for both complexes in aqueous medium from UV absorption spectra by using the Benesi-Hildebrand method; the relative stability constants at room temperature were calculated at 2700 +/- 300 L mol(-1) and 750 +/- 50 L mol(-1) for isoproturon and diuron, respectively. In the solid state, inclusion processes with beta-cyclodextrin were characterized by means of infrared and Raman techniques and confirmed by X-ray diffraction spectra.