Derivation of a Revised Model for Activity Calculation in Multisilicate Melts

Hollitt's model for prediction of thermodynamic properties in multicomponent silicate melts has been revised to better reflect network modifier depolymerization effectiveness as a function of basicity and melt composition. This model is based on the free energy changes in a melt caused by the breaking of silicate polyions by the addition of basic oxides; these free energy changes are in turn related to the change in the concentration of various oxyanion molarities caused by such additions. Application of the revised model to actual systems shows good agreement with experimental data; possible model improvements are discussed.     

CHARACTERIZATION OF THE POWER SPECTRUM OF FORCE-DEFORMATION RELATIONSHIPS OF CRUNCHY FOODS1

The mean magnitude of the power spectra of the compressive force-deformation relationships of breadsticks, pretzels and zwiebacks, exposed to five levels of relative humidity, was determined at various cutoff frequencies. In all three foods the mean magnitude had a linear correlation with the Fractal dimension of the normalized original force-deformation relationship, regardless of the cutoff frequency. This implies that the jaggedness of the force-deformation curve, which is most probably a manifestation of the material crunchiness or crumbliness, can be quantified by an additional single numerical index, the mean magnitude of the power spectrum. The correlation's independence of the cutoff frequency is an indication that the loss of crunchiness, as a result of moisture sorption, can be expressed in the shape of the whole spectrum and not only in its high frequency region.     

ACHIEVING FLEXIBLE AUTONOMY IN MULTIAGENT SYSTEMS USING CONSTRAINTS

Organizations influence many aspects of our lives. They exist for one reason: they can accomplish things that individuals cannot. While recent work in high-autonomy systems has shown that autonomy is a critical issue in artificial intelligence (AI) systems, these systems must also be able to cooperate with and rely on one another to deal with complex problems. The autonomy of such systems must be flexible, in order that agents may solve problems on their own as well as in groups. We have developed a model of distributed problem solving in which coordination of problem-solving agents is viewed as a multiagent constraint-satisfaction planning problem. This paper describes the experimental testbed that we are currently developing to facilitate the investigation of various constraint-based strategies for addressing the coordination issues inherent in cooperative distributed problem-solving domains.     

DAWN OF THE DEAD CITY: AN EXPLORATORY ANALYSIS OF VACANT ADDRESSES IN BUFFALO,NY 2008–2010

ABSTRACT: This article examines residential vacancy patterns in Buffalo, NY, using data from a unique data set. It includes variables from HUD Aggregate USPS Administrative Data on Address Vacancies, the American Community Survey (ACS) 5‐year estimates for 2005–2009, housing choice voucher (HCV) records of local public housing agencies, and municipal in rem property records. Multiple regression is used to identify significant relationships between vacancy patterns, socioeconomic characteristics, and institutional factors. The findings from this analysis suggest that the percent of vacant residential properties increases in census tracts with elevated poverty rates, higher percentages of renters receiving rental assistance, and long‐term vacancies. They also suggest that the percent of abandoned residential properties increases in census tracts with highly concentrated black populations, elevated poverty rates, long‐term vacancies, and higher percentages of business addresses. We conclude that these relationships are unique to older core cities experiencing systemic population and job losses. These cities struggle with a distinct type of long‐term vacant and abandoned structures, which we label zombie properties. They can be contrasted with vacant and abandoned properties in transitional or regenerating areas. We offer recommendations for further analysis of zombie properties in these urban settings.     

Producing and experiencing Harlow: neighbourhood units and narratives of New Town life 1947–53

This paper uses the notions of ‘Utopias of escape’ and ‘Utopias of reconstruction’ to help conceptualize the New Town movement and, in particular, the settlement at Harlow, built from 1947 onwards and located 25 miles north‐east of London. The analysis focuses on the neighbourhood unit as the means by which this and other New Towns were built, and centres on the ideological presuppositions of Modern architects and planners intending to shape modern citizens through the architectural designs provided in Harlow. As a counterpoint to this, perspectives provided by residents of these neighbourhood units are analysed alongside the architectural expressions. As such, a complex narrative of space and place is developed, which not only broadens the traditional approach of architectural geography beyond the ideas of architects and planners, but allows a much fuller interpretation of these spaces to be made. The argument focuses on the two schemes designed by Maxwell Fry and Jane Drew in Harlow: those of Tany's Dell and The Chantry housing groups. The paper concludes with some thoughts on the nature of the historiographical narratives written on planning and experiencing New Towns and the potential ambiguity of such (hi)stories.     

Wine bottle closures: physical characteristics and effect on composition and sensory properties of a Semillon wine 1. Performance up to 20 months post-bottling

A Semillon wine was bottled using 14 different closures: a screw‐cap type, two grades of conventional natural cork, two ‘technical cork’ closures (natural cork with a synthetic component), and 9 closures manufactured from synthetic polymer material. Closure performance was evaluated for physical aspects (e.g. extraction force and energy, change in closure diameter, and ease of closure reinsertion), and for wine composition and sensory properties. Wine under the screw cap closure retained the greatest concentration of sulfur dioxide (SO₂) and ascorbic acid and had the slowest rate of browning. For other closures the trend of SO₂ loss relative to the screw cap closure was apparent from an early stage of testing, and was most evident in the group of synthetic closures, intermediate in the conventional corks, and least evident in the technical cork closures. The loss of SO₂ was in general highly correlated with an increase in wine browning (OD₄₂₀) and the concentration of SO₂ in the wine at six months was a strong predictor of future browning in the wine, particularly after eighteen months. Neither the concentration of dissolved oxygen at bottling (0.6–3.1 mg/L), nor the physical closure measures were predictors of future browning. For several closures upright storage tended to accelerate loss of SO₂ from the wine, but in many cases this effect was marginal. The closures differed widely in regard to physical characteristics, and in general synthetic corks appeared least ‘consumer‐friendly’ in terms of extraction forces, energies, and ease of closure re‐insertion, but there was a trend for natural cork closures to exhibit larger variability in physical characteristics than technical cork and synthetic closures. Sensory analysis indicated large differences in wine flavour properties, with closures which tended to result in the best retention of free SO₂ having wine sensory scores for ‘citrus’ that were generally high whilst scores for the attributes ‘developed’/‘oxidised’ were low. The situation was reversed for wine under closures that performed poorly in the retention of free SO₂. It was found that below a critical level of free SO₂ remaining in the wine, closures exhibited substantially higher ‘oxidised’ aroma. Whilst trichloroanisole‐type (TCA) taint was a noticeable problem for some cork and technical cork closures, any plastic‐type taint appeared not to be a problem with most synthetic closures.     

EARLY RESIDENT EXPERIENCES AT A NEW MIXED‐INCOME DEVELOPMENT IN CHICAGO

ABSTRACT: Mixed‐income development is an increasingly popular poverty deconcentration strategy in the United States but there have been few in‐depth studies about the experiences of residents once they move in to the new housing developments. This article explores the early experiences of residents of all income levels who have moved into a new mixed‐income development on the south side of Chicago. In‐depth interviews have been conducted with 46 residents of the development, including 23 former public housing residents. Interviews were also conducted with a comparison group of 69 public housing residents who did not move to the development. I find that public housing movers appear to be a substantially different group than non‐movers. I find that overall satisfaction with the new development is quite high among residents of all income levels. Early social relations are limited, particularly across income levels, and there are key barriers to interaction, such as physical design, stigma and assumptions based on class and housing status, and segregated associational structures.