Measurement of solid fat content by ultrasonic reflectance in model systems and chocolate

A series of confectionery coating fat (CCF) and cocoa butter (CB) dispersions in corn oil were prepared and tempered to a range of temperatures (10, 12 and 15 °C and 26, 27.5 and 29 °C respectively) to produce samples with solid fat contents (SFC) between 0 and 9%. The ultrasonic velocity in the CCF samples increased with increasing SFC and decreased with temperature, however the CB samples were too attenuating to allow velocity measurements. The ultrasonic reflectance at the surface of both sets of dispersions decreased linearly with SFC but at the same level of solids was less for CB than CCF suggesting some dependence on other aspects of fat structure. The microstructures and thermal properties of the fat systems are compared in an attempt to understand these structural differences. Finally ultrasonic reflectance is shown to respond to changes in a chocolate melt during tempering.     

The Appropriation of the Material of Places in the Landscape: the case of tufa and springs

Springs have long been recognized as being significant places in the landscape, and there is ample evidence of later-prehistoric and Roman activity at spring sites. The Christian appropriation of springs as 'places', either indirectly by assigning their origin to saints, or directly by building chapels and churches on spring-head sites, is also well evidenced. The possibility that the material of petrifying springs - tufa - was both transplanted and appropriated, and that the symbolic properties of the material may go back well into British prehistory, is explored.     

Does marital conflict cause child maladjustment? Directions and challenges for longitudinal research.

Although the association between marital conflict and child adjustment problems has been well documented, there is no empirical evidence that conflict actually causes maladjustment. The investigation of causation requires theoretically and empirically informed longitudinal research. Two topics are addressed to facilitate such research. First, how marital conflict may lead to adjustment problems is outlined, with a focus on constructs that are likely to be critical to any theory on this topic. Second, several issues are identified that need to be addressed in longitudinal research on the mechanisms underlying the link between marital and child problems. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Morphological analysis of poly(o-methoxyaniline) thin-films deposited by spin coating technique

Morphological study of conducting polymer thin films obtained by spin coating is reported. Poly(o-methoxyaniline) films were deposited onto glass substrates and analyzed by profilometry and atomic force microscopy (AFM). It is shown that final thickness is correlated by a power law with spin speed with a solution concentration varying coefficient and that surface roughness decreases with increasing spin speed.     

Humans: the missing link in manufacturing simulation?

Computer based discrete event simulation (DES) is one of the most commonly used aids for the design of automotive manufacturing systems. However, DES tools represent machines in extensive detail, while only representing workers as simple resources. This presents a problem when modelling systems with a highly manual work content, such as an assembly line. This paper describes research at Cranfield University, in collaboration with the Ford Motor Company, founded on the assumption that human variation is the cause of a large percentage of the disparity between simulation predictions and real world performance. The research aims to improve the accuracy and reliability of simulation prediction by including models of human factors.     

Effects of mastication on the distribution of molecular weights and on the mechanical properties of native and commercial dental gutta percha (trans-polyisoprene)

Mastication of gutta percha (trans-polyisoprene) resulted in the selective scission of molecules, producing a narrower distribution of lower molecular weights. The mechanical properties of the samples also underwent a significant change due to mastication. The greater the content of incompatible substances (salts and oxides) in commercial gutta percha. the more substantial were these effects. The atmosphere (air, N₂, O₂) in which the experiments were conducted yielded significantly different results. The decrease in molecular weight was far greater in an O₂ atmosphere than under a current of nitrogen or air, owing to the combination of double bonds with O₂.     

Environmental effects on ductile-phase toughening in Nb5Si3-Nb composites

A variety of materials have been toughened via the addition of a ductile phase. Brittle silicide intermetallics such as Nb₅Si₃ have been significantly toughened by niobium particles incorporated during in-situ processing techniques. In the work described here, toughness tests conducted on Nb₅Si₃ were monitored in a scanning electron microscope to view the process of toughening provided by the niobium particles. In particular, the behavior of the ductile phase was monitored and related to the toughness obtained. In an attempt to vary the behavior of the ductile phase, the composite materials were exposed to a variety of gaseous environments and subsequently tested in air. The resulting toughness, resistance-curve behavior, and in-situ results highlight the importance of the behavior of the ductile phase on subsequent properties.