Specification methods for material-handling control algorithms in flexible manufacturing systems

Good methods are needed to specify, test, and debug material-handling control logic. This article surveys a number of representative methods for defining and describing control algorithms for programmable material-handling equipment used in flexible manufacturing systems. The methods are evaluated with regard to their suitability for communication between people and as bases for interfaces to automatic program generators. It is concluded that no single method is entirely satisfactory. Three methods (position diagrams, function block diagrams, and operation networks) have potential to be combined into an effective hybrid approach that minimizes the need for the user to switch between various conceptual models.     

Effect of dose rate and length of storage on the ESR signal strength in irradiated chicken bone

One hundred and twenty-five pairs of chicken drumsticks were randomly allocated to one of five dose rates: 5, 10, 15, 20 or 600 kGyh-. The highest dose rate was obtained using a linear accelerator whilst the remaining dose rates were provided using a ⁶⁰Co gamma source. Each batch of 25 pairs was further divided into groups five of which were stored at 4°C for 0, 7, 14, 21 or 28 days. ESR spectroscopy was used to measure the intensity of the radiation-induced signal. There was a quadratic relationship between ESR signal strength and dose rate, which although statistically significant is unlikely to be of practical importance. The magnitude of the ESR signal declined by about 20% over the first 14 days of storage at 4°C and thereafter the decrease was minimal.     

Automated fluorimetry in quality control of pasteurized and ultra-high temperature-treated starch soup

Automated monitoring of the microbiological quality of heat-processed foods by the resazurin reduction test was applied to microtitration plate incubator-fluorimeter technology. The appearance and disappearance of the fluorescing peak of resorufin was monitored on microtitration trays. Pasteurized or ultra-high temperature-treated starch-based soup was used as the model food system. Bacillus subtilis spores (ultra-high temperature treatment) and vegetative cells of Enterococcus faecalis (pasteurization) were inoculated into the soup before the heat treatment at levels which resulted in some survival. The timing of appearance of maximum fluorescence correlated with the number of bacteria in pre-incubated samples. Automated resazurin-reduction fluorimetry was compared with conventional plating, turbidometry and microcolony count by the direct epifluorescent filter technique. The results of the resazurin test correlated well with those of all the other methods tested. Fluorimetry had the advantage that the results could be read within 1–5h and the reproducibility was superior to the other methods.     

Mashing of rice with barley malt under non-conventional process conditions for use in food processes

Non-conventional mashing conditions are relevant in the development of a lactic acid-fermented soymilk beverage where mashed rice is the source of carbohydrates for the fermentation and sweetness of the beverage. Advantages in the process layout could be achieved by mashing at higher pH and lower malt concentrations than normally used in the brewing industry. the work reported here assessed the consequences of mashing under non-conventional conditions. Malt concentration in the cereal part was varied from 25% to 70% (w/w), pH was varied within 5.3 to 7.1, and prolongation of the holding times at 50°C and 62°C was investigated. Regression equations have been established for predicting yields of soluble protein, low molecular weight sugars and total fermentability as functions of pH and malt concentration. the results showed that the maltose yield was constant while glucose, maltotriose and total fermentable sugar yields decreased slightly with increasing pH and decreasing malt concentration. Prolonged mash holding times at 50°C and 62°C gave minor increases in protein yields only. It is concluded that it is quite acceptable to use non-conventional mashing conditions when a mashing step is integrated in other food processes.     

Rapid analysis of polymer homologues and additives with SFE/SFC-MS coupling

A rapid and easy analysis method for polymers is presented. The method involves sample preparation by SFE, separation of the extracted compounds by SFC and simultaneous quantitative detection by FID, as well as identification of unknowns by MS. The applications illustrate how structural research work and routine polymer analysis can be done with this time saving method.     

Application of SiC-Si functionally gradient material to thermoelectric energy conversion device

Because of its high–temperature chemical stability, SiC ceramic is a promising material for high-temperature device applications such as thermoelectric energy converters. However, the electrical conductivity of SiC ceramic is too low for it to be used as a thermoelectric energy converter at the cold junction. Therefore, we propose a SiC-Si functionally gradient material (FGM) in order to improve the electrical conductivity of the SiC ceramic at the cold junction. An SiC rod was fired in a temperature gradient furnace. One end of the SiC rod was maintained at 2473 K and the other end was maintained at 1973 K for 30 min. After firing, the porous SiC edge fired at 1973 K was dipped into molten Si in order to infiltrate molten Si into the porous SiC. The microstructure of the FGM is classified into three regions: the SiC-Si composite material; the porous SiC ceramic; and the densified SiC ceramic. The electrical conductivity, the Seebeck coefficient and the thermal conductivity for each region of SiC-Si FGM was measured at 300 K; a figure of merit was calculated. The figure of merit of the SiC-Si FGM at the cold junction, at room temperature, was 10⁸ times higher than that of a nongradient SiC ceramic.     

Thin conducting polypyrrole film on insulating surface and its applications

An electrically conductive plastic material was obtained by the polymerization of pyrrole on insulating polymeric materials and nylon cloth impregnated with the oxidant by vapour phase technique, resulting in a uniform, smooth and adherent coating of conducting polymer having a surface resistance ranging from 200 Ω/□ to 20 kΩ/□, which makes it suitable for applications as an antistatic material.     

Effect of irradiation and packaging type on sensory quality of chill-stored turkey breast fillets

A panel of experienced assessors was used to test the effect of irradiation at 2.5kGy (250krad) on the sensory quality of 1-day and 21-day-old turkey breast fillets stored at 1°C in either oxygen-permeable polythene or an oxygen-impermeable barrier film. In the application of Free Choice Profiling and Generalized Procrustes Analysis, assessors used their own terms to describe the appearance, odour and flavour of the samples.
The irradiated samples showed negligible growth of micro-organisms across 21 days of storage. Radiation treatment resulted in an intense pink colour in the raw and cooked samples, which was maintained during storage in oxygen-impermeable film, but decreased in samples exposed to oxygen during storage. Radiation also produced a set of unpleasant raw odour notes variously described as sour, rancid, mature, bad meat or putrid in the samples stored in oxygen-impermeable film. These notes were unlike the sulphurous notes previously associated with protein denaturation in irradiated chicken and were apparently distinct from the odour notes that developed in corresponding non-irradiated samples.     

Dynamic buffering performance of the honeycomb paperboard filled with polyurethane

A new kind of composite buffering material was made by filling the voids of honeycomb paperboard with polyurethane. Drop tests were performed to evaluate the dynamic energy absorption capacity of the material. Based on the tests results, we analyzed the mechanical behaviors of the material under different conditions and obtained the inherent influencing laws of some factors on the material＇s dynamic buffering performance. It was shown that the dynamic buffering performance varied directly with impact velocity, and inversely with the void diameter, thickness and buffeting area of the composite material.