Machine planning in a product model environment

In recent years the integration of computer-based design and manufacture activities has received significant research effort as it has major potential to improve industrial performance. Product modelling is becoming accepted as the mechanism by which a central source of product data can be captured to provide an integrating mechanism between a range of design and manufacture functions. This paper describes the use of activity and data modelling methods to define an integrated planning system. From this an experimental system has been produced, building and integrating machine planning functions in a CAE system, employing a product modelling environment. The software implementation of this concentrates on planning and NC code generation functions for the machining of 2½-dimensional prismatic components from solid stock on a three-axis vertical machining centre.     

Performance deterioration in optimum linear systems

Uncertainty in dynamical systems may arise due to inaccuracies in modelling, parameter variations and external disturbances. As a result of this uncertainty, the performance index of an optimal control system deviates from its optimum value, which is referred to as the deterioration. A technique is presented to find a bound on the deteriorated performance index of optimum linear systems subject to bounded uncertainty. Uncertainty is incorporated as a forcing term in the system equations. To find the deteriorated performance bound, the performance index subject to the uncertain system is to be maximized within a specified time interval. The interchange theorem is used to interchange the maximizing and integral operations in the performance index functional to obtain a pointwise problem. Then, a Lyapunov technique, used to find reachable sets of uncertain systems, is applied to find the pointwise maximum values. The method serves as a measure of performance robustness or a measure of sensitivity to uncertainties. The problem is analytically solved for first-order systems. Finally, examples concerning first- and second-order systems are given as applications of the technique.     

Experimental evidence for spring and autumn windows for the detection of geobotanical anomalies through the remote sensing of overlying vegetation

This paper reports a second year's (1981) results of a field geobotanical remote-sensing study in central Virginia, the objective of which was to investigate the relationship between mineralization and reflectance from vegetation. The objective of the 1981 work was specifically to test the generality and reproducibility of the previous year's results.

Four pairs of sites in the Virginia Piedmont were used, two near the town of Mineral, Louisa County, and two in Buckingham County. At each site oak trees, predominantly white oaks (Quercus alba L.), and tulip poplar (Liriodendron tulipifera L.), were identified as close as possible to the nodes of a 4 × 4 grid. Leaf samples were taken at regular intervals during the growing season and their reflectances in bands corresponding to LANDSAT Thematic Mapper (TM) bands 3, 4 and 5 were measured using a three-band hand-held radiometer. Selected leaf and soil samples were analysed for elemental concentrations of certain micronutrients and macronutrients. Analysis of variance (ANOVA) techniques were used to analyse the variation in leaf reflectance. From this we found that neither asimuth about the tree nor height in the canopy were significant, but significance was found in the difference between tulip populars and oaks. While the leaf reflectances possess a great deal of natural variation, we also found a pattern of significant differences in TM bands 3 and 5 for oaks and tulip poplars in the early autumn which we can discern over 2 years and for three out of four site pairs separated by 90 km. There is also significant variation in oak and tulip popular leaf reflectances over the spring between site pairs, but the pattern of this significance is less clear. TM band 4 data explained a small amount of variation in the spring

More subtle relationships between leaf reflectance and mineralization were examined by regressing leaf-reflectance variables upon concentrations of trace metals in the soil. The quality of the fit of such models was dependent upon time of the growing season. The quality of fit of the models involving TM bands 3 and 5 weregreatest during the early autumn and late spring.TM band 4 showedslight significance in the spring. Models involving tulip poplars possessed a lesser quality of fit and significance and were shifted more towards the spring as compared with the models involving oak samples. These results establish spring and autumn windows for detection of metal sulphide related, geobotanical anomalies in the remotely sensed data. The autumn window appears to be related to earlier senescence of the mineralized vegetation. The spring window was examined further in the spring of 1982, by observing the overwintering recovery period. From these observations we found that the non-mineralized vegetation flushed or leaved out earlier than the mineralized vegetation. It appears therefore the spring and autumn windows are manifestations of the compression of the growing season for mineralized vegetation visavis non-mineralized vegetation     

Automated thresholding and analysis of microCT scanned bread dough

Computer aided x‐ray microtomography is an increasingly popular method to investigate the structure of materials. Continuing improvements in the technique are resulting in increasingly larger data sets. The analysis of these data sets generally involves executing a static workflow for multiple samples and is generally performed manually by researchers. Executing these processes requires a significant time investment. A workflow which is able to automate the activities of the user would be useful. In this work, we have developed an automated workflow for the analysis of microtomography scanned bread dough data sets averaging 5 GB in size. Comparing the automated workflow with the manual workflow indicates a significant amount of the time spent (33% in the case of bread dough) on user interactions in manual method. Both workflows return similar results for porosity and pore frequency distribution. Finally, by implementing an automated workflow, users save the time which would be required to manually execute the workflow. This time can be spent on more productive tasks.     

The effect of calcium addition on the rheological properties of a soft cheese at various stages of manufacture

The effects of calcium on the rheology of a model soft cheese at different stages of manufacture have been assessed. Several batches of reconstituted skim milk with 9% w/v and four calcium concentrations (0.14, 0.35, 0.88, 2.2 mM) were used to make a soft stretchable cheese whose rheological characteristics, G' (storage modulus or elastic component) and G' (loss modulus or viscous component), at different stages of manufacture, were measured using a Stress Controlled Rheometer. Calcium had a significant effect on the rheology of the soft cheese; however, it affected each rheological parameter differently .     

Effect of calcium on the minerals retention and cheesemaking parameters of milk

The objective of this study was to evaluate the effect of calcium on minerals retention and cheesemaking parameters of milk during manufacture of a model soft cheese. Several batches of both reconstituted skim milk containing 9, 12 and 15% (w/v) and whole milk with 12, 15 and 18% (w/v) of total solids were used to prepare a soft 'stretchable' cheese of the mozzarella type. A small amount of added calcium (0.14 mM) influenced the level of minerals and some of the measured cheesemaking parameters (clotting time, weight of whey, protein and fat recovery), but the efficiency of the cheesemaking process was lower than would be expected in commercial terms .     

An evaluation of the LacTek Beta-Lactam Milk Screening Kit

The LacTek Beta-Lactam Milk Screening Kit (an enzyme immunoassay) was compared to the Delvotest P method (a microbial inhibition test) for detecting antibiotics in raw milk samples. Good agreement (97·8%) was obtained from a total of 413 raw milk samples tested in four laboratories, The LacTek test has been accepted as a rapid (less than 10 minutes) antibiotic screening method for inclusion in the Joint Committee of the Milk Marketing Board and the Dairy Trade Federation Code of Practice for the Assessment of Milk Quality.     

Analysis of Factors Influencing Colour Matching in Package Dyeing

Automated dyeing can be successfully accomplished only if all the variables that affect the final colour are held within limits that keep the accumulated effect on colour within acceptable tolerances. The number of variables is large and the magnitude of the effect of each factor on colour must be assessed in order to determine the degree of process control to be imposed on each factor to meet any prescribed standard of colour matching. A comprehensive investigation of the many variables, using a statistical factorial type of design (termed skeleton factorial design), is described. These designs reduce the experimental work to reasonable proportions and enable simple estimates to be made of the effect of each factor. Colour variations were assessed instrumentally and translated into colour-difference terms using a uniform colour-difference co-ordinate system. Simulation work assessed the colour variation consequent upon random variation of groups of factors with given standard deviation. From this work, it was possible to construct limits of accuracy that had to be maintained, at each relevant process, to achieve dye lots that were within the prescribed tolerances at the end of each automated dyeing cycle.