Laboratory studies into how glass-reinforced plastic (GRP) vat surfaces can be repaired without causing migration of styrene into foodstuffs

Glass–fiber-reinforced plastic (GRP) vats are used widely for the storage of foodstuffs and potable water. As the inner surfaces deteriorate during decades of use, they need to be repaired. The unsaturated polyester resins that are used for recoating are crosslinked with styrene which can cause taint and odor problems. This article describes some coating parameters that affect the content of residual styrene and its subsequent migration. The influences of cure temperature and duration, along with the effect of washing with warm detergent solution, were investigated. Cured specimens were tested for their residual styrene content and for styrene migration into the food simulants, distilled water, 3% acetic acid, and 15% ethanol. The dominant factor in reducing the amount of residual styrene is the temperature. The resin self-heats as it cures, typically up to 50°C. Thus, any further lowering of the styrene content requires a higher cure temperature than this. A 3-h cure at 80°C reduced both the residual content and the migration levels by about 100-fold. At lower cure temperatures, the heating effect of washing at 60°C is more important than the washing effect of the detergent. When less catalyst was used the residual styrene levels rose dramatically, from 70 to 360 to 1300 mg/kg for the normal dose, half and quarter the normal dose, respectively. There was a linear relationship between residual content in the GRP and the migration levels. This correlation could be used for monitoring the quality of vats repaired in situ, using styrene-based coating resins.     

Cover Image,Volume 97, Issue 11

The cover image, by Hannah C Wells et al., is based on the Research Article Deer leather: analysis of the microstructure affecting pebble, DOI: 10.1002/jsfa.8199 .

     

Effect of high temperature annealing on scratch behavior of acrylonitrile styrene acrylate copolymers

The scratch behavior of butyl-acrylate rubber-modified styrene-acrylonitrile (ASA) upon high temperature annealing is investigated following the ASTM D7027/ISO 19252 linearly increasing normal load test methodology. The critical normal loads at the onset of the major deformation transitions along the scratch path, such as groove formation, scratch visibility, microcrack formation, and plowing, are reported and quantitatively analyzed. It is found that the scratch resistance improves with high temperature annealing, i.e., 30 °C above T_g, as compared to annealing below or around T_g. Microscopic investigation suggests that the increase in scratch resistance is related to the changes in surface morphology of the polymer. It is concluded that performing high temperature annealing enhances the scratch performance without compromising ASA bulk properties. Implication of the present study for improving scratch resistance of polymers is discussed.     

Carbon Nanotubes: Biocompatibility of Immobilized Aligned Carbon Nanotubes (Small 8/2011)

In vivo host responses to an electrode‐like array of aligned carbon nanotubes (ACNTs) embedded within a biopolymer sheet are reported. This biocompatibility study assesses the suitability of immobilized carbon nanotubes for bionic devices. Inflammatory responses and foreign‐body histiocytic reactions are not substantially elevated when compared to negative controls following 12 weeks implantation. A fibrous capsule isolates the implanted ACNTs from the surrounding muscle tissue. Filamentous nanotube fragments are engulfed by macrophages, and globular debris is incorporated into the fibrous capsule with no further reaction. Scattered leukocytes are observed, adherent to the ACNT surface. These data indicate that there is a minimal local foreign‐body response to immobilized ACNTs, that detached fragments are phagocytosed into an inert material, and that ACNTs do not attract high levels of surface fouling. Collectively, these results suggest that immobilized nanotube structures should be considered for further investigation as bionic components.     

Science, ethnicity, and bias: Where have we gone wrong?

The quality, quantity, and funding of ethnic minority research have been inadequate. One factor that has contributed to this inadequacy is the practice of scientific psychology. Although principles of psychological science involve internal and external validity, in practice psychology emphasizes internal validity in research studies. Because many psychological principles and measures have not been cross-validated with different populations, those conducting ethnic minority research often have a more difficult time demonstrating rigorous internal validity. Thus, psychology's overemphasis of internal as opposed to external validity has differentially hindered the development of ethnic minority research. To develop stronger research knowledge on ethnic minority groups, it is important that (a) all research studies address external validity issues and explicitly specify the populations to which the findings are applicable; (b) different research approaches, including the use of qualitative and ethnographic methods, be appreciated; and (c) the psychological meaning of ethnicity or race be examined in ethnic comparisons. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Contrast-based evaluation of mar resistance of thermoplastic olefins

The physical aspect of mar behavior is studied by applying a standardized progressive sliding load methodology to smooth and textured automotive-grade thermoplastic olefins. It is shown that surface texture has a strong effect on light scattering and, hence, the propensity for mar visibility. It is also shown that digital imaging via a desktop scanner can be used to quantitatively and objectively assess mar resistance using contrast as a basis. Incorporation of slip agent definitively improves the mar resistance for both types of surfaces. Relationships between contrast, gloss and surface roughness in relation to mar visibility are discussed.     

The diversification of psychology: A multicultural revolution.

The National Multicultural Conference and Summit was held in January 1999 in California. Hosted by Divisions 17 (Counseling Psychology), 35 (Society for the Psychology of Women), and 45 (Society for the Psychological Study of Ethnic Minority Issues), the event drew support from many American Psychological Association (APA) divisions and other organizations and sponsors. Approximately 550 psychologists and graduate students attended the conference, which was intended to (1) examine state-of-the-art issues in ethnic minority psychology, (2) identify barriers to becoming a multicultural profession, and (3) forge alliances for political action and advocacy. The summit participants unanimously endorsed resolutions aimed at implementing cultural competence in all psychological endeavors. Multicultural themes arising from the summit included the diversification of the US; the facilitation of difficult dialogues on race, gender, and sexual orientation; spirituality as a basic dimension of the human condition; the invisibility of monoculturalism and Whiteness; and the teaching of multiculturalism and diversity. APA was strongly encouraged to take the lead in seeing that multicultural competence becomes a defining feature of psychological practice, education and training, and research. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effects of stand-up and sit-down meeting formats on meeting outcomes.

The effects of meeting format (standing or sitting) on meeting length and the quality of group decision making were investigated by comparing meeting outcomes for 56 five-member groups that conducted meetings in a standing format with 55 five-member groups that conducted meetings in a seated format. Sit-down meetings were 34% longer than stand-up meetings, but they produced no better decisions than stand-up meetings. Significant differences were also obtained for satisfaction with the meeting and task information use during the meeting but not for synergy or commitment to the group's decision. The findings were generally congruent with meeting-management recommendations in the time-management literature, although the lack of a significant difference for decision quality was contrary to theoretical expectations. This contrary finding may have been due to differences between the temporal context in which this study was conducted and those in which other time constraint research has been conducted, thereby revealing a potentially important contingency—temporal context. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Glass-Related Injuries in Oklahoma City Bombing

When a terrorist bomb explodes in an urban area, it produces devastating effects, including structural and nonstructural damage to buildings, injuries, and deaths. Numerous injuries in explosions result directly and indirectly from window glass failure. Direct glass-related injuries occur when glass shards flying and falling from fractured windows cause lacerations and abrasions. Secondary glass-related injuries occur when the shock front of the blast wave passes into buildings through fenestrations vacated by fractured glazing. The Oklahoma city bombing killed 167 people and caused numerous injuries. Most of the deaths and many of the injuries occurred in the Alfred P. Murrah Federal Building, the target of the bomb. This event focused the attention of the engineering and security communities on two major issues: the prevention of progressive structural collapse and the design of blast-resistant glazing. This paper discusses glass-related injuries that occurred away from the Alfred P. Murrah Federal Building in Oklahoma City. In particular, it provides information concerning locations of glass-related injury victims in other buildings with respect to their position in proximity to outside walls with glazing. Location data indicate that more than one-quarter of the glass-related injury victims in buildings were positioned within 1.5 m (5 ft) of a wall with glazed fenestrations and nearly one-half of the glass-related injury victims were positioned within 3.0 m (10 ft) of a wall with glazed fenestrations. In addition to suffering lacerations and abrasions, a large number of victims in buildings suffered hearing damage because glazing that failed to maintain closure of fenestrations exposed them to the shock front of the blast wave. Consideration of the injury data justifies a requirement for design of blast-resistant glazing to protect building inhabitants.