INCORPORATION OF THE SLOWING DOWN EFFECT INTO A MILL MODEL

ABSTRACT

The one-dimensional mixing model predicts mill residence time distributions which match reasonably well win an RTD determined experimentally on a ball mill. Assuming that the model applies along the mill length, the combined mixing-breakage equation set can be solved numerically, allowing for variation of specific rates of breakage along the mill as a function of the fineness of charge at each position along the mill. The slowing-down of breakage rates of materials measured in a small laboratory mill was used to illustrate the decrease of capability in a continuous mill.     

The applicability of a laser triangulation probe to non-contacting inspection

This paper highlights the main advantages of non-contacting inspection and discusses the methods adaptable for the dimensional inspection of engineering components by using a compact solid-state laser triangulation sensor on a computer-assisted co-ordinate measuring machine (CMM). The machine used is the bridge-type Granite 80 model of the LK Tools Company. The methods described are equally applicable for similar inspection work by using industrial robots. The motivation for looking at non-contacting inspection methods is also discussed.     

Effect of Modified Atmosphere Storage on C. Botulinum Toxigenesis and the Spoilage Microflora of Salmon Fillets

Modified atmosphere (MA) storage in conjunction with refrigeration has been shown to significantly increase the shelf life of fresh fish and other products, but the effects, if any on the outgrowth and toxigenesis of C. botulinum are unknown. A commercial system was duplicated in the laboratory and the effects of modified atmosphere on the outgrowth of C. botulinum types A, B, and E were observed in inoculated salmon fillets and sandwiches stored at 4.4°C and 22.2°C. Inoculated samples stored in air at the same temperatures were used as controls. No toxigensis was observed in either the air or modified samples stored at 4.4°C, but all inoculated samples held at 22.2°C were toxic within 2–3 days. Spoilage generally preceded toxigenesis. In a concurrent study, the tendency of CO₂ environments to repress the growth of gram negative bacteria to a greater extent than gram positive bacteria was also noted.     

Starter culture effects on caprine yogurt fermentation

The growth rate of the starter culture and its effects on the gelation process of caprine milk were determined. Caprine milk was fermented using various levels of starter culture inoculum and the acidification, growth and gelation profiles were obtained. The caprine yogurt samples inoculated with lower starter culture levels (1% and 1.5% wlv) produced gel structures about eight to 10 times stronger than that made using a 2% v/v inoculum. The gelation patterns suggested that the formation of the gel structure during the caprine yogurt fermentation was time dependent. This behaviour may be due to the presence of higher cell numbers in the caprine yogurt system.     

Aspartame Degradation Kinetics as Affected by pH in Intermediate and Low Moisture Food Systems

Kinetics of aspartame degradation in low to intermediate moisture systems were evaluated by incorporating aspartame into agar/micro-crystalline cellulose model systems. They were prepared at pH 3, 5, and 7, equilibrated after freeze-drying to three water activities (0.34, 0.56, and 0.66), and stored at 25 to 45°C. Aspartame in such systems was most stable at pH 5 and became less stable as pH decreased or increased. As the molar buffer salt concentration increased, the rate of aspartame degradation increased. The activation energy ranged from 23 to 36 kcal/mole.