Globally stable and exponentially convergent adaptive control

In this paper three new adaptive control strategies for linear discrete-time single-input/single-output plants are proposed. They enable globally stable and exponentially convergent adaptive controllers to be designed based on various approaches, such as pole placement and optimal LQ. The principle idea of the strategies proposed is to apply a fixed-parameter control law while the estimates of the plant parameters leave some appropriately chosen region. The persistency of excitation of some external signals is crucial for the stability analysis of an overall adaptive system.     

EFFECT OF TREATMENT OF STARCHY WATER ON QUALITY OF PASTA DURING CONTINUOUS COOKING

Industrial continuous pasta cookers are filled with thousands of liters of cooking water. During the cooking process, the starch leaches from the cooked pasta. As the starch concentration increases, the cooked pasta becomes less firm and stickier. Starchy water must be constantly released to reduce the starch concentration. This requires addition of fresh makeup water and energy used to reheat it. The effects of presteaming freshly extruded pasta and posttreatment at high temperature and pressure of the starchy cooking water on the pasta cooking quality was tested. The posttreatment consisted of elevating the water temperature to 120C and the pressure to 1.0297 × 10 ⁵ Pa. The viscosity of cooking water decreased from 1.039 × 10^?5 m²/s to 7.280 × 10^?6 m²/s as a result of the temperature degradation of amylose. Applying high pressure/temperature treatment to the cooking water, as well as straining it through a tight mesh screen, makes it possible to use the same cooking water for a longer period of time. This, in turn, reduces the wastewater produced in continuous cookers, without decreasing the quality of cooked pasta. This results in the conservation of the water and energy.