-Designing an effective criterion and learning algorithm for find the best structure is a major problem in the control design process. In this paper, the fuzzy optimal control methodology is applied to the design of the feedback loops of an Exothermic Continuous Stirred Tank Reactor system. The objective of design process is to find an optimal structure/gains of the Robust and Optimal Takagi Sugeno Fuzzy Controller (ROFLC). The control signal thus obtained will minimize a performance index, which is a function of the tracking/regulating errors, the quantity of the energy of the control signal applied to the system, and the number of fuzzy rules. The genetic learning is proposed for constructing the ROFLC. The chromosome genes are arranged into two parts, the binary-coded part contains the control genes and the real-coded part contains the genes parameters representing the fuzzy knowledge base. The effectiveness of this chromosome formulation enables the fuzzy sets and rules to be optimally reduced. The performances of the ROFLC are compared to these found by the traditional PD controller with Genetic Optimization (PD_GO). Simulations demonstrate that the proposed ROFLC and PD_GO has successfully met the design specifications.

No abstract

The optimization of the formulation (nature and content of chemical components) and the technical parameters of the shaping-up process of ceramic insulators (in replacement of those in glass) are the objectives of this study. The decontamination of SiO2 (solid-liquid extraction of Fe xOy) and the increase of both BaO and ZrO2 amounts (while Na2O is partially eliminated) and the firing temperature allowed a significant increase of all the phys-mechanical and insulating properties at the commercial frequency 50-60 Hz. Samples with 15 mm diameter and 2 mm thickness and others for mechanical properties were needed. The characterization concerned Ba-Zr(Al xSi1-x)O3 ceramic samples. By data computing of the test results, a new "computed" formulation (Ba-stabilized and Zr doped mullite) showed excellent phys-mechanical (density, viscosity, flexural and traction strengths) and insulating properties (transversal resistivity, dielectric strength).

In this study, the effect of substitution of feldspar by soda-lime glass waste (SLGW), on rheological behavior, thermal, physical-mechanical and structural properties of sanitary-ware vitreous china (VC) bodies, has been evaluated. The findings show a positive effect on the rheological behavior of the slip, to viscosity, thixotropy, density and casting process. Indeed, during the firing stage at 1230°C, the use of 20 wt. % of SLGW in the composition of VC bodies, improved Bulk density (2 to 2.52 g/cm3), reduced water absorption (0.35 to 0.02%), and increased flexural strength (33 to 51 MPa). The fired samples were characterized using X-ray diffraction, SEM and FTIR analysis; results indicate that Mullite and Quartz are the major phases, with a little presence of anorthite phase formed by SLGW additions. From TGA/DTG analysis, it was found that the use of SLGW (15 wt. %) reduces mass loss of VC bodies (8.83 to 8.53%). These positive results open new horizons for using this waste, as a sound environmental, technological and economic solution.

No abstract