Scheduling/rescheduling in the manufacturing operating system environment†

A scheduling/rescheduling procedure is proposed for real-time control of a computerized manufacturing facility managed by a central manufacturing operating system. The procedure implies schedule revisions upon significant operational changes such as machine breakdowns. Experiments to evaluate the total production time of a computerized manufacturing system with breakdowns under scheduling/rescheduling have yielded advantages of between 25% to 7-0% compared to fixed sequencing and priority despatching procedures, respectively. Computation times required for the scheduling procedures on a CDC 65OO/66OO have also been studied. The scheduling/rescheduling procedure for an actual facility required less than two minutes, and the computation time can be regulated by the selection of parameters in an approximate method of scheduling.

     

Heat-induced Gelation of Myosins/Subfragments from Chicken Leg and Breast Muscles at High Ionic Strength and Low pH

Heat-induced gelation was studied to examine the reason for marked differences in gel strength of myosins at 0.6M KCl and pH 5–6. When leg myosin (L-myosin) or L-myosin tail subfragment was mixed with breast myosin (B-myosin) or B-myosin tail subfragment, rigidity of the mixture gel was higher than the sum of rigidities of the component gels. Difference in strength of heat-induced gel between L- and B-myosin seemed to be caused by differences in filament-forming ability and in gel-forming ability of head and tail segments of both kinds of myosins.     

Antimicrobial Effects of Pressured Carbon Dioxide in a Continuous Flow System

The application of microbubbles of pressured CO₂ greatly increased CO₂ concentration in the solution treated. By treatment at 6 MPa, 35°C and average residence time 15 min, L. brevis was completely inactivated at the level of dissolved CO₂,γ≧ 11 (γ, Kuenen's gas absorption coefficient). E. coli and S. cerevisiae required γ≧ 17, and T. versatilis required γ≧ 21 for complete inactivation. Z. rouxii could be sterilized at 20 MPa and 26. A comparison of the continuous and batch method showed that L. brevis was inactivated completely under pressured CO₂ > 0.16 g/cm³ with the continuous method and >0.9 g/cm³ with the batch method.     

An approximate solution of machine scheduling problems by decomposition method

To obtain an approximate solution for a large-scale job-shop scheduling problem the decomposition method was investigated. This means that an original problem is decomposed into subproblems, which are solved separately, and then the solution of the original problem is composed from the subproblems' solutions. Different methods to decompose the problem were tested by computational experiments and evaluated from the viewpoint of the goodness of schedule and computation time.     

Robust control for a constantly rising temperature system (Hm control approach)

Thermoluminescence dating has attracted the attention of geology and archaeology researchers as a new method. This method requires a heating device to raise the temperature of the specimens at an exact rate. This paper describes the design method of a control system that can achieve this goal. This control system lends to be unstable because of the existence of the parameter perturbation and dead time. In this paper, the perturbation and dead time are treated as perturbations of a nominal plant regarded as a first-order lag time system. Improvement of tracking characteristics in the low-frequency domain and robust stability in the high-frequency domain of the control system are achieved by using the solution of the mixed-sensitivity problem that is a kind of H^∞ control theory. Experiments verify the effectiveness of this method.     

Formation of Defects in Glass Under Electron Bombardment

Needlelike crystals grew from a fragment of glass bombarded with intense electron beams in an electron microscope. This phenomenon was limited to glasses containing mobile atoms such as Na and Pb, to fresh surfaces, and to the part of the sample not coated with carbon film. When there was a relatively thick carbon film on the surface, prolonged electron bombardment caused the formation of bubbles within the fragments.