Effect of Blanching and Drying on Pectin Constitutents and Related Characteristics of Dehydrated Peaches

The effects of sulfuring, blanching, dehydration, and storage (of dehydrated fruits), on the pectic constitutents and other characteristics of peaches are reported. Adequate blanching stabilized pectins of the dehydrated peaches so higher rehydration capacity and lower rehydration losses were observed after 5 min blanching. Increase in degradation was observed in nonblanched or 1.5 min heat-treated fruits, which resulted in lower rehydration capacity. A significant correlation was found between the contents of total pectin and protopectin fractions and the firmness or rehydration ratio of the peaches. Thus, pectin, one of the major cell-wall and intercellular tissue components, plays a significant role in determining the textural-structural characteristics of dehydrated fruits.     

WATER SIMULATION OF SODIUM REACTORS

The thermal hydraulic simulation of a large sodium reactor by a scaled water model is examined. The Richardson Number, friction coefficient and the Peclet Number can be closely matched with the water system at full power and the similarity is retained for buoyancy driven flows. The simulation of thermal-hydraulic conditions in a reactor vessel provided by a scaled water experiment is better than that by a scaled sodium test. The results from a correctly scaled water test can be tentatively extrapolated to a full size sodium system.     

Influence of heat and sulphur dioxide treatments on some quality characteristics of intermediate-moisture banana

The effect of duration of heat treatment (blanching) on the firmness, dehydration rate, colour, and pectin esterase (PE) activity, was investigated in sulphited, unsulphited, blanched and non heat-treated intermediate-moisture banana (IMB). The product was significantly firmer if the bananas had been blanched, and in either event, firmness as measured with a texturometer, also increased with increasing SO₂ concentration. The average rate of water removal (dehydration) increased, with increasing blanching time, up to about 4 min, and increased also with increasing SO₂ concentration. There was a decrease in PE activity in both blanched and non-heat-treated IMB, with increasing SO₂ content. The effect of sulphiting on pectolytic enzyme activities does not appear to have been reported previously.     

Role of Acetaldehyde Production in the Removal of Astringency from Persimmon Fruits under Various Modified Atmospheres

Astringency of persimmons was removed by enclosing the fruits in polyethylene bags under vacuum or by replacing air with N₂ or CO₂. Acetaldehyde produced by the fruit under these conditions accumulated at different rates. The rate of the deastringency process was directly proportional to the level of acetaldehyde accumulation. Thus, the fruit held at 20°C in CO₂ was the first to lose its astringency, but showed internal browning after 1 wk. Fruits under vacuum or N₂, where less volatiles accumulated, maintained their high quality and firmness for 2 wk at 20°C or 3 months at ? 1°C. However, fruit held under vacuum began to show internal browning when acetaldehyde accumulated above a certain level.     

Positive Column Plasma in a Neon Discharge at Medium Pressures†

The present paper concentrates on the experimental investigation of the behaviour of steady-state plasma columns in a neon discharge for a pressure range of 2-32 mm Hg. The electron temperature T _e, the electron concentration across the centre-line tube n _o, the electron radial distribution n(r), the axial electric field E and the ionic current density at the discharge tube walls are determined. The experimental results are compared to the theoretical data obtained in the model proposed by Kagan and Ljagushchenko (1964 a, b). For our experimental conditions a good agreement is obtained between theory and experiment.     

Expert system for autonomous handling of elementary assembly operations†

This paper addresses the new conception of a real-time expert system for elementary two-arm assembly operations under the inclusion of operation-based vision. Every operation is represented by a local blackboard which contains a recognition part, a world model and a measurement part. The total set of these behaviour-oriented modules is supervised and scheduled by an operation monitor, which is again a blackboard. The local-knowledge sources of each individual blackboard receive sensor signals as input and can directly produce a reaction without going to a higher-level global-inference engine. This local, short connection between sensor signal and reflex is decided on the basis of compiled rules which have the form of production rules. The main types of these rules are regulation tasks depending on the operation and analysis rules for situation assessments. Global plans are produced as assembly graphs and transmitted in parts to the operation monitor as task specifications. A 3-D CAD modeller is used to support the object representation and recognition     

PREDICTION OF VORTEX-INDUCED VIBRATION OF LONG FLEXIBLE CYLINDERS MODELED BY A COUPLED NONLINEAR OSCILLATOR:INTEGRAL TRANSFORM SOLUTION

The Generalized Integral Transform Technique(GITT) was applied to predict dynamic response of Vortex-Induced Vibration(VIV) of a long flexible cylinder.A nonlinear wake oscillator model was used to represent the cross-flow force acting on the cylinder,leading to a coupled system of second-order Partial Differential Equations(PDEs) in temporal variable.The GITT approach was used to transform the system of PDEs to a system of Ordinary Differential Equations(ODEs),which was numerically solved by using the Adams-Moulton and Gear method(DIVPAG) developed by the International Mathematics and Statistics Library(IMSL).Numerical results were presented for comparison to those given by the finite difference method and experimental results,allowing a critical evaluation of the technique performance.The influence of variation of mean axial tension induced by elongation of flexible cylinder was evaluated,which was shown to be not negligible in numerical simulation of VIV of a long flexible cylinder.