A Review of “Elderburbia: Aging With a Sense of Place in America”

A problem in applying benefit-cost analysis to planning issues is the difficulty of imputing values to public goods like water quality. During the past thirty years, the contingent valuation (CV) survey method has been institutionalized as a technique for valuing these types of goods. This article traces the development of the method and summarizes recent federal guidelines. Examples from three recent studies, involving willingness to pay for nonpoint-source pollution controls, are used to illustrate issues about the technique. Considerations for planners who must undertake or evaluate CV studies are discussed.     

Rippled and Helical MoS<Subscript>2</Subscript> Nanowire Catalysts: An Aberration Corrected STEM Study

Abstract  

Aberration corrected (C_s) scanning transmission electron microscopy (STEM) has been used for the first time to characterize MoS₂ catalysts (supported on Al₂O₃ substrates) to provide detailed information of its shape and structure. The high-resolution imaging reveals unprecedented morphologies present in the MoS₂ catalyst that have never been observed before with other experimental techniques because of the insufficient image contrast and/or resolution. High angle annular dark field (HAADF)-STEM images shows very clearly that the catalyst is formed by elongated chains with a twisted and helical structure. Based on the HAADF-STEM images, we built three atomic models to illustrate the different morphologies found in the MoS₂ catalyst. The existence of these nanostructures opens the posibility for novel catalyticaly active edge morphologies in MoS₂-based nanocatalysts.     

Space fission reactor structural materials: Choices past,present, and future

Nuclear powered spacecraft will enable missions well beyond the capabilities of current chemical, radioisotope thermoelectric generator and solar technologies. The use of fission reactors for space applications has been studied for over 50 years. Structural material performance has often limited the potential performance of space reactors. Space fission reactors are an extremely harsh environment for structural materials with high temperatures, high neutron fields, potential contact with liquid metals, and the need for up to 15–20 year reliability with no inspection or preventative maintenance. Many different structural materials have been proposed. While all of those proposed meet many of the requirements for space reactor service, none satisfy all of them. However, continued development and testing may resolve these issues and provide qualified materials for fission reactors for space power.     

The effect of prior flexural prestrain on the stability of structural steel columns

Prior large bending deformations may cause a significant reduction in the buckling stress of a mild steel strut subjected to direct compression. Although the work arose in investigating the properties of mangled bars, that is bars which have been deliberately deformed so as to reduce initial geometric imperfections, the conclusions are equally applicable to other instances of plastic strain reversal, such as those which might arise due to earthquake or shock waves. Particular attention is drawn to the possibly potentially dangerous situation which may arise when a severely deformed element is straightened and then subjected to loading conditions which would be regarded as safe for a previously undeformed element. Buckling stresses have been computed from material data for the prestrained specimens and these values are compared with actual test results.     

Mobilization of adsorbed copper and lead from naturally aged soil by bacterial extracellular polymers

Sorption of pollutants is a dominant phase transfer process affecting the fate and transport of metals through the subsurface. The movement of contaminants is retarded by sorption to the stationary subsurface porous media and can seriously hinder remediation efforts. Research has shown that the binding of adsorbed metals becomes more pronounced the longer the contaminant is in the subsurface and the release rates of aged metal contaminants have not received the research attention given to freshly added metals in laboratory studies. Metal release rates are also influenced by the presence of dissolved ligands that compete with mineral soil surfaces by providing binding sites. Dissolved organic matter such as bacterial extracellular polymers are common in natural soil solutions and the metal binding properties of bacterial polymers are well established. Therefore, binding of metals to dissolved biopolymers may result in mobilization of an adsorbed metal. This is important for cases where the metals are assumed to be relatively immobile such as in the case of land applied biosolids. In addition, naturally occurring adherent bacteria commonly produce extracellular polymers and thus may modify the bioavailability of meal contaminants at the point of their attachment. In this study samples from three sites, one a land applied sludge test site, were used to investigate the ability of bacterial extracellular polymers to release metals from soils with long-term exposures. The presence of ?200mg/L bacterial extracellular polymer was found to increase the short-term (less than 350h) release of Cu and Pb by a factor of 2-4-fold.     

New Professionalism: the post-industrial context

Definitions and perceptions of professionalism are continually challenged and transformed by public need, government interaction and institutional organizations. When the goals of those three entities are focused on near-term results, this poses a significant threat to the integrity, value and relevance of professional services. When the individual and corporate professional's profit margin, corporate shareholder responsibility and news media sensationalism are factored in, this short-termism dynamic is greatly magnified. Built environment professions are seen as particularly vulnerable to this threat, given that investments in buildings and infrastructure have long-life and high-performance service expectations. This commentary responds to the Building Research & Information special issue entitled ‘New Professionalism’ (2013, volume 40, number 1) and situates the predicament of built environment professionals within an emerging historical transition: that of the post-industrial information society with its characteristic knowledge workers and cybernetic bases of production. Long-term virtues of the built environment mission such as sustainability, public good and evidence-based design are shown to be reflections of the transition from industrial era short-termism to post-industrial systemic foresight. This commentary supplements the special issue papers with a discussion on the broader academy's potential role in breaking the stranglehold of contemporary short-termism in the built environment professions.     

Frank Lloyd Wright and the Concrete Slab and Column

This paper traces the development of Frank Lloyd Wright's ideas on the place of the concrete column and slab in architecture. It deals with his first employment of the slab at Unity Temple (Oak Park, 1904) and his use of the form in residential projects during the next few years. It surveys American literature on concrete construction and briefly analyses the contribution of Claude A.P. Turner and the employment of the Turner system in two Chicago buildings that Wright would have known. It discusses his project for the San Francisco Call (1912) and the use of the Barton system in the Richland Center warehouse for A.D. German (1915). It further discusses his first probable knowledge of the more sophisticated concrete slabs of Maillart, published in 1926, and of Maillart's invention of a proto lily-pad capital. This capital is also to be seen in Wright's champagne glass designed for Leerdam (1930) and in his project for the Salem Capitol Journal of 1931. Finally it is argued that the much admired lily-pad columns at the Johnson Wax office building (Racine, 1937-39) are really a series of three-hinged bents rather than shell construction.