Mathematical modelling of the alcoholic fermentation of glucose by Zymomonas mobilis mobilis

The kinetics of alcoholic fermentation of a strain of Zymomonas mobilis, isolated from sugarcane juice, has been studied with the objective of determining the constansts of a non-structured mathematical model that represents the fermentation process. Assays in batch and in continuous culture have been carried out with different initial concentrations of glucose. The final concentrations of glucose, ethanol and biomass were determined. The following kinetic parameters were obtained: μ_max, 0·5 h^?1; K_s, 4·64 g dm^?3; P_max, 106 g dm^?3; Y_x/s, 0·0265 g g^?1; m, 1·4 g g^?1 h^?1; α, 17·38 g g^?1; β, 0·69 g g^?1 h^?1.     

Mining fuzzy association rules from low-quality data

Data mining is most commonly used in attempts to induce association rules from databases which can help decision-makers easily analyze the data and make good decisions regarding the domains concerned. Different studies have proposed methods for mining association rules from databases with crisp values. However, the data in many real-world applications have a certain degree of imprecision. In this paper we address this problem, and propose a new data-mining algorithm for extracting interesting knowledge from databases with imprecise data. The proposed algorithm integrates imprecise data concepts and the fuzzy apriori mining algorithm to find interesting fuzzy association rules in given databases. Experiments for diagnosing dyslexia in early childhood were made to verify the performance of the proposed algorithm.     

Influence of PS‐b‐PEO diblock copolymers on the compatibility of syndiotactic polystyrene modified epoxy blends

Homogeneous solutions of syndiotactic polystyrene (sPS) in diglycidylether of bisphenol A (DGEBA), containing 2.5, 5 and 7.5 wt % of thermoplastic with or without 0.5 and 1 wt % of poly(styrene‐b‐ethylene oxide) (PS‐b‐PEO) block copolymer, were polymerized using a stoichiometric amount of an aromatic amine hardener, 4,4′‐methylene bis (3‐chloro‐2,6‐diethylaniline) (MCDEA). The dynamic‐mechanical properties and morphological changes of sPS‐(DGEBA/MCDEA) compatibilized with different amount of PS‐b‐PEO have been investigated in this paper. The addition of the block copolymer produced significant changes in the morphologies generated. The size of the dispersed spherical sPS spherulites does not change significantly, but less spherulites of sPS appeared upon network formation in the systems with compatibilizer, what means that addition of compatibilizer in this system delayed crystallization of sPS in sPS‐(DGEBA/MCDEA) systems and change phase separation mechanism from crystallization‐induced phase separation (CIPS) and reaction‐induced phase separation (RIPS) almost only to RIPS. Moreover, PS‐b‐PEO with higher molecular weight of PS block seems to be a more effective compatibilizer than one with lower molecular weight of PS block. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 479–488, 2006     

Event-driven,pattern-based methodology for cost-effective development of standardized personal health devices

Experiences applying standards in personal health devices (PHDs) show an inherent trade-off between interoperability and costs (in terms of processing load and development time). Therefore, reducing hardware and software costs as well as time-to-market is crucial for standards adoption. The ISO/IEEE11073 PHD family of standards (also referred to as X73PHD) provides interoperable communication between PHDs and aggregators. Nevertheless, the responsibility of achieving inexpensive implementations of X73PHD in limited resource microcontrollers falls directly on the developer. Hence, the authors previously presented a methodology based on patterns to implement X73-compliant PHDs into devices with low-voltage low-power constraints. That version was based on multitasking, which required additional features and resources. This paper therefore presents an event-driven evolution of the patterns-based methodology for cost-effective development of standardized PHDs. The results of comparing between the two versions showed that the mean values of decrease in memory consumption and cycles of latency are 11.59% and 45.95%, respectively. In addition, several enhancements in terms of cost-effectiveness and development time can be derived from the new version of the methodology. Therefore, the new approach could help in producing cost-effective X73-compliant PHDs, which in turn could foster the adoption of standards.     

Porous poly(2-hydroxyethyl acrylate) hydrogels prepared by radical polymerisation with methanol as diluent

Dynamic-mechanical and water sorption properties of porous and non-porous hydrogels have been studied as a function of their porosity and crosslinking density. Porous hydrogels with different crosslinking densities were prepared by co-polymerisation of 2-hydroxyethyl acrylate and ethyleneglycol dimethacrylate in solution in methanol. Pores were formed due to the segregation of the solvent from the polymer network during the polymerisation process. The porosity of the samples was observed by scanning electron microscopy. The pores collapse during the drying process after polymerisation but they reopen when the xerogel is immersed in liquid water. Bulk polymer networks with varying crosslinking densities were also synthesised and used as a reference in the analysis of the porous hydrogels. Water sorption from the gas phase and from the liquid phase was studied by means of equilibrium sorption isotherms and immersion experiments, respectively. Dynamic-mechanical spectroscopy conducted on the xerogels shows that the elastic modulus in the rubber-like state highly depends on the amount of solvent used in the polymerisation what is attributed to the presence of discontinuity surfaces in the xerogel although the pores are closed.