Stress in Leached Phase-Separated Glass

When a phase-separated glass is leached, stresses develop because of release of thermal stresses, creation of surface area, ion exchange, and hydration. Analyses are presented for the thermal stresses, including the portion that develops on cooling from the heat-treatment temperature to the setting temperature of the less viscous phase. During leaching, the interfacial energy of the residual phase increases, so that phase tends to contract. A more important effect is the contraction caused by removal of alkali and B₂O₃ from the residual phase during leaching. The extent of removal of B₂O₂ decreases with heat-treatment time, t_H , because the scale of the microstructure increases as t^1/3_H. The change in residual B₂O₂ content with t_H is shown to be consistent with diffusion-controlled ion exchange. The dependence of stress on t_H in partially leached glasses, measured by Drexhage and Gupta, results principally from the change in extent of ion exchange; the reduction in surface area with increasing t_H also has a significant effect on the stresses.     

Cure Levels, Processing Methods and Meat Source Effects on Low-fat Frankfurters

Frankfurters were manufactured from lean meats (100% beef and 50:50 beef-pork) to contain reduced levels of fat (about 1.3%). A curing solutibn was added to yield 160% of fresh meat weight. Three processing methods, coarse ground tumbled, fine ground tumbled and fine ground emulsified were used. All products were cooked in live steam to 71°C internal temperature. Product yields, penetrometer values, color, chemical composition, caloric content and added water were evaluated. Emulsified frankfurters from 50:50 beef-pork mixtures at 160% cure had texture similar to conventional product as well as increased (P<0.05) yields, acceptable color and 74% fewer calories.     

Soybean Hulls as an Iron Source for Bread Enrichment

Soybean hulls, a concentrated source of iron, may have potential as a source of iron fortification in baked products. Retention of ⁵⁹Fe in rats from white bread containing intrinsically labeled soybean hulls did not differ significantly (p<0.05) from extrinsically labeled white bread fortified with bakery grade ferrous sulfate (70.4 and 63.1%, respectively). Physical and sensory evaluations of bread containing up to 5% soybean hulls did not differ from white bread in loaf volume, cross-sectional area, tenderness or overall acceptance. These results suggest that soybean hulls are a good source of available iron and may be added to bakery products without deleterious effects in baking performance and sensory acceptability.     

CHARACTERISATION OF PATTERNS OF CHEWING BEHAVIOUR IN HUMAN SUBJECTS AND THEIR INFLUENCE ON TEXTURE PERCEPTION

Electromyography was used as a noninvasive and unobtrusive technique to characterise chewing patterns for a range of foods. Differences between subjects for a variety of aspects of chewing sequence are recorded for a range of foods (carrot, apple, roast pork, salami, biscuit and toast). Identifiable subgroups of subjects differing in chewing behaviour existed within the random sample of 52 dentate subjects. The five subgroups accounted for 52%, 21%, 11%, 10% and 6% of the sample population. Major discriminating factors between the behavioural groups lie in their chewing time and the muscle work rate during chewing. Sensory ratings for firmness and rubberiness of model foods differed significantly between the subjects exhibiting different chewing behaviours. Chewing behaviour may influence consumers' perceptions about the texture of a food.     

THE EFFECT OF ELECTRICAL STIMULATION ON THE PALATABILITY AND CONSUMER ACCEPTANCE OF BONELESS RIB STEAKS

A total of 25 cattle (5 purebred Simmental, Limousin, or Chianina bulls and 10 each of steers and heifers (1/2 blood Simmental, Limousin, or Chianina) 11 to 15 months of age and with carcasses weighing approximately 270 kg, after approximately 255 days on a high concentrate ration, were utilized to evaluate the effects of electrical stimulation upon the palatability and consumer acceptance of boneless rib steaks. The right side of each carcass was electrically stimulated at 400 V (AC 50 to 60 cycles/sec) using a hog stunner with a maximum output of 5 amps, immediately after splitting, while the left side served as an unstimulated control. Boneless rib steaks were presented to an experienced taste panel (1/side) and distributed to household consumers (4/side) for evaluation of overall tenderness and the acceptability of flavor, juiciness, tenderness, and overall palatability. Significant (P <0.05) treatment effects were not observed in cooking losses, consumer acceptance, or any of the palatability attributes evaluated, indicating that prerigor electrical stimulation, prior to chilling, did not produce meaningful differences in these traits, with the type of cattle and conditions employed in this study.     

Growth of the Acid-Tolerant Fungus Scytalidium acidophilum as a Potential Source of Single-Cell Protein

An acid-tolerant fungus, Scytalidium acidophilum, was cultivated in peat extract for potential use as a single-cell protein (SCP) source. In shake flask fermentations with a 0.3% yeast extract diluted peat extract medium, it was found that the best conditions for growth occurred at pH 2.0 and 25°C. The maximum biomass concentration was produced after 10 days, with no significant differences for agitation rates between 100 and 200 rpm. Microbial contamination was not observed in nonaseptic operations. The protein content and amino acid composition of the mycelium produced compares with those reported for S. acidophilum grown in other fermentation media. The advantages of growing S. acidophilum in acid peat extract are presented.     

Conditions for exponomial output control

A closed-form expression for the output of a multivariable linear system with an input that is the product of a polynomial vector and an exponential function is derived without reference to the theory of the Laplace transform. When the exponent of the exponential factor in the input coincides with one of the natural modes (eigenvalues) of the system, the Drazin inverse of a matrix is used to derive a closed-form expression for the output. Using this expression, necessary and sufficient conditions for an input to produce a predetermined output are derived. These conditions are expressed in terms of a block matrix known as the system matrix. These results include some results appearing in the literature dealing with the problem of characterizing those input functions that will yield zero output. A tracking result is included which shows that, for a stable system, asymptotic tracking of a predetermined reference signal is possible if, and only if, the signal can be tracked instantaneously.     

Equivalence of quadratic performance criteria†

Two quadratic cost functionals are defined to be equivalent, if they generate the same optimal control law. Necessary and sufficient conditions are derived in terms of the system parameters and the quadratic weighting matrices for two cost functionals to be equivalent.     

A note on the observed and predicted flow patterns around islands— Flat Holm,the Bristol Channel

Abstract

Multispectral scanner (MSS) data from the Natural Environment Research Councils (NERC) aircraft flown over the island of Flat Holm in the Bristol Channel, U.K. have been used in association with a System Probatoire d'Observation de la Terre, high-resolution visible scanner (SPOT HRV) image of the same area to identify the major surface water flow patterns around the island. Theoretical scaling parameters for shallow water flows are used to predict wake form and compared with the MSS and SPOT HRV images. Initial results indicate that the mathematical approach gives a useful approximation to the observed flow patterns though additional information on tidal currents throughout the tidal cycle and detailed bathymetry in the area are required to further the predictive model.