Use of near infrared spectroscopy to evaluate the intensity of extrusion-cooking processing of pea flour

Twenty-five different pea extrudates were produced using a Clextral BC45 twinscrew extruder. Near infrared reflectance (NIR) spectra of the extrudates were recorded between 1100 and 2500 nm. the application of principal component analysis (PCA) on these spectral data permitted discrimination between the extrudates produced under moderate, intermediate or severe conditions of extrusion-cooking. the study of protein quality through solubility experiments, polyacrylamide gel electrophoresis, determination of available basic amino acids and brown colour measurement showed that, under moderate conditions of extrusion-cooking, protein was only slightly affected. All protein subunits could be restored after solubilization in phosphate buffer containing a detergent and a reducer of disulphide bonds. However, under severe conditions of extrusion-cooking, the extrudates exhibited a relatively intense brown colour and all protein fractions were implicated in non-disulphide covalent bonds and underwent some macromolecular degradation. Therefore, the spectral discrimination between pea extrudates which was related to the processing parameters, could also be related to the degree of transformation of these extrudates. Thus, the method may be used to classify an extrudate produced under unknown conditions by projecting its spectrum on the similarity maps obtained by PCA on a known collection of extrudates.     

Microcomputer-based expert systems: where we are, where we are headed

Abstract: While the idea of developing 'true' expert systems in the current microcomputer environment continues to be a subject of derision among serious AI researchers, undaunted developers and designers of microcomputer-based systems continue to make progress on the personal computer front. This article presents an overview of the current state of expert systems in a microcomputer environment and then offers some prognostications about the near-term future of expert systems on desktop and personal computers. It is suggested that the history of software developments on the small computers indicates that a pattern of growth exists. If this same pattern is applied to expert systems, the author contends, the near-term future of micro-based knowledge-based systems is at least forecastable if not predictable.     

Analysis of Fracture Probabilities in Nonuniformly Stressed Brittle Materials

The results of theoretical studies on the effect of nonuniform stress fields encountered in prismatic beams under bending on the fracture of brittle materials are described. Derivations were carried out to determine the risk of rupture of bending specimens subjected to a symmetrical four-point load of arbitrary spacing, the symmetric three-point loading and pure bending forming limiting cases of this more general loading. The analysis was based on materials obeying the Weibull distribution function with assumptions for either volumetric or surface flaw dispersion conditions. The predicted strengths of bending and tensile specimens are compared. An analytical method for the determination of the three Weibull parameters from a pure bending test is proposed. This method, based on the best fit of a theoretical curve to the experimental data, was applied successfully to experimental results on Columbia Resin, a brittle amorphous polymer.     

Electrical Conductivity of Iron-Doped NiO Single Crystal at Equilibrium and During Internal Oxidation

The dc electrical conductivity of (Ni_{1- x} Fe _x )O single crystals (0.01 < x < 0.09) has been measured at controlled oxygen partial pressure, at temperatures ranging from 1170 to 1490 K. The behavior of single-phase (Ni,Fe)O is characterized as a function of temperature, oxygen partial pressure, and iron content, and interpreted in terms of diffusive transport of the electronic charge carriers. From in situ electrical conductivity measurements performed during the internal oxidation of (Ni,Fe)O to a two-phase mixture of "NiO"+ NiFe₂O₄, kinetics data for the internal oxidation are inferred.     

The Slow Pace of Rapid Technological Change: Gradualism and Punctuation in Technological Change

Discussions of technological change have offered sharply contrastingperspectives of technological change as gradual or incrementaland the image of technological change as being rapid, even discontinuous.These alternative perspectives are bridged using the punctuatedequilibrium framework of evolutionary biology. Using this framework,it is argued that the critical event is not a transformationof the technology, but speciation—the application of existingtechnology to a new domain of application. As a result of thedistinct selection criteria and the degree of resource abundancein the new domain, a new technological form may emerge. Thenew technological form may be able to penetrate other nichesand, in particular, may precipitate a process of ‘creativedestruction’ and out-compete prior technologies. Thisframework is applied to an historical study of wireless communicationfrom the early experimental efforts of Hertz to the modern developmentof wireless telephony.     

Characteristics of Frozen Desserts Sweetened with Fructose and Lactose

Combinations of fructose and lactose were used as the major sweetening agents in ice cream-type frozen dessert formulations. In addition to the sweeteners, variable amounts of caseinate were subjected to a 2³ factorial experimental design in order to evaluate the most suitable combinations of lactose (4.5% or 5.5%), fructose (7.5% or 8.5%) and sodium caseinate (2% or 3%). Comparative chemical, physical and sensory analyses indicated that a formulation using 5.5% lactose, 8.5% fructose and 2% sodium caseinate gave product acceptability similar to that of an ice cream of standard ingredient array and composition.