A variable radius roll adhesion test (VaRRAT) suitable for measuring the adhesion of paint to metal

Early trials and analysis of a new adhesion test are discussed. The test is designed for measuring the adhesion of paint to deformable steel sheets as used in building, automotive, and other cladding applications, and does not require detailed knowledge of the paint mechanical properties. A stiff overlay, such as an epoxy resin, is applied to the coating, and the steel substrate is peeled away using a roll of well-defined radius to which the steel substrate is constrained. The propagation of a crack within the paint or at some interface in the paint/metal system depends mostly on the mechanical properties and thickness of the overlay and the radius of the constraining roll. The test is shown to discriminate better than existing practical adhesion tests between paints of expected differing adhesion/cohesion, but also presents some inconsistencies that require further work to resolve. BHP Institute of Steel Processing and Products, Wollongong NSW 2522, Australia.     

Microstructural changes in concretes with sulfate exposure

In prior papers the responses of concretes to 50,000 ppm MgSO₄ exposure depending on cement type, w/cm and the presence of slag were described. The present paper completes this analysis by examining the effects of immersion of concretes produced using slag blended cements, in solutions containing 50,000 ppm of sodium sulfate. The spatial evolution of microstructure associated with carbonation and sulfate attack show differences which can be related to the nature of the cation associated with the sulfate, the cement type, and the w/cm ratio.     

Mothers' supervision of their children's peer play: Relations with beliefs, perceptions, and knowledge.

Mothers (N?=?76) of 3- to 5-year-old children completed questionnaires assessing beliefs in the importance and modifiability (vs. innateness) of children's peer relationship skills, perceptions of their children's social competence with peers, and strategies they would use in response to children's peer interaction problems. A subsample of mothers (n?=?34) was observed supervising the play of their own children and a peer. Maternal perceptions of children's competence were negatively associated with the extent of mothers' involvement in children's play, whereas the quality of supervision was predicted by knowledge of socialization strategies and the interaction of beliefs and knowledge. Beliefs appeared to moderate the effects of maternal knowledge on mothers' behavior in that knowledge was associated with the quality of supervision only when mothers believed social skills were important and modifiable. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Geotechnical Investigation Strategies for Lunar Base

Geotechnical characterization of potential lunar sites will be a critical part of the planning and design process. The strategies used to conduct a geotechnical investigation will be dictated by the specific needs of the lunar base, the unique environment of the lunar surface, and general character of the lunar soils and rocks. This paper outlines some of the types of geotechnical information that will be important and identifies some of the more promising strategies which might be used to obtain such information in the lunar environment. Some of the most important geotechnical information for planning and site development will be related to construction in the lunar soil. In addition to construction concerns, geotechnical data for foundation design (or verification of predesigned foundations) will be needed. The geotechnical site‐characterization work should include geophysical techniques, supplemented by conventional mechanical boring and testing only to the degree necessary to correlate geophysical measurements with conventional soil properties and to investigate anomalies. Equipment used for geotechnical site characterization will also serve for mineralogical exploration. Several techniques for geotechnical investigation that may provide very useful information in an expedient manner are described. Geophysical methods include seismic and electromagnetic methods, including seismic surveys that utilize surface waves. Electromagnetic methods such as ground‐penetrating radar are fast, efficient methods for mapping the subsurface, although these techniques do not measure soil characteristics that can readily be correlated with engineering properties. Seismic methods provide information that may correlate with soil strength, compressibility, and excavatability. In‐situ physical testing will likely include penetration testing for direct physical measurement of lunar soil behavior.     

Encountering misspellings and spelling performance: Why wrong isn't right.

Experience with misspellings can be detrimental to subsequent spelling performance. Generating or being exposed to incorrect spellings between two successive spelling tests interfered with subsequent spelling accuracy of these same words in Experiments 1 and 2 (but not Experiment 3), as indicated by changes from correct to incorrect spellings (CI changes). Furthermore, significantly more CI changes occurred when a recognition test (with incorrect versions as distractors) followed a dictation test than when a second dictation test followed it. Repeatedly presented misspellings were rated as looking progressively more similar to the correct spelling across presentations (Experiment 3). These outcomes suggest that spelling tests that involve the discrimination of correct from incorrect versions may be ill advised. In addition, the instructional technique encouraging students to intentionally produce misspellings of words, for purposes of visual comparison, may be detrimental rather than helpful. (PsycINFO Database Record (c) 2010 APA, all rights reserved)