A network of adaptive Kalman filters for data channel equalization

The aim of this paper is to revisit the Kalman filtering-based approach of channel equalization. Indeed, Kalman equalizers have already been proposed in the literature as an alternative to more classical structures. However, these Kalman solutions are based on the assumption of Gaussian signals that is not valid in the context of data channel equalization. From an approximation of the density functions of the data signals by a weighted sum of Gaussian probability density functions, we here propose a new structure of an equalizer that is based on a network of Kalman filters operating in parallel. An adaptive version of this network is investigated. It includes the on-line estimation of the channel and of the noise variance     

Simulation and cost estimate for biodiesel production using castor oil

Brazilian government has established a regulation that imposes the commercialization of diesel blended with 3% of biodiesel by volume. Castor oil has being considered an option to guarantee the supply of biodiesel needed. For this reason, in this work, a continuous biodiesel plant was designed and simulated in HYSYS simulator using castor oil as feedstock. The developed process was capable of producing biodiesel at high purity using an alkali catalyst. Material and energy flows, as well as sized unit operations were used to conduct an economic assessment of the process. Total capital investment, total manufacturing cost and after annual equivalent cost were also calculated. A study of production costs was performed considering the fluctuations of the raw material prices and the glycerin purification step.     

On the stability radii of continuous-time infinite Markov jump linear systems

In this paper we introduce the subject of stability radii for continuous-time infinite Markov jump linear systems (MJLS) with respect to unstructured perturbations. By means of the small-gain approach, a lower bound for the complex radius is derived along with a linear matrix inequality (LMI) optimization method which is new in this context. In this regard, we propose an algorithm to solve the optimization problem, based on a bisectional procedure, which is tailored in such a way that avoids the issue of scaling optimization. In addition, an easily computable upper bound for the real and complex stability radii is devised, with the aid of a spectral characterization of the problem. This seems to be a novel approach to the problem of robust stability, even when restricted to the finite case, which in turn allows us to obtain explicit formulas for the stability radii of two-mode scalar MJLS. We also introduce a connection between stability radii and a certain margin of stability with respect to perturbations on the transition rates of the Markov process. The applicability of the main results is illustrated with some numerical examples.     

Determination and Evaluation Employing Multivariate Analysis of the Mineral Composition of Broccoli (Brassica oleracea L. var. Italica)

Broccoli (Brassica oleracea L. var. Italica) is a vegetable food that belongs to the family Cruciferaceae, and it is a good source of vitamins and minerals. Among other characteristics, the kind of culture (conventional or organic), the climate of origin, and the way a vegetal will be consumed influence directly in the concentrations of minerals. The aim of this work was to determine mineral composition (Fe, Mn, Zn, K, Ca, Mg, and Na) of 16 broccoli samples collected in four cities of Bahia, Brazil, in summer and winter, from organic and conventional cultures. These elements were also determined in a lot of raw and cooked summer samples and then all results were evaluated using multivariate analysis. Broccoli samples were analyzed by inductively coupled plasma optical emission spectrometry after digestion with HNO₃ and H₂O₂. The results expressed as milligrams of element per 100 g of sample demonstrated that the concentration ranges for conventional and organic broccoli varied, respectively, from 0.13 to 0.90 and 0.14–1.18, for iron; from 0.15 to 1.79 and 0.04–1.40, for manganese; from 0.20 to 1.58 and 0.17–1.28, for zinc; from 317.65 to 484.45 and 321.58–521.78 for potassium; from 7.14 to 153.50 and 9.38–131.55, for calcium; from 21.09 to 47.15 and 29.51–61.23, for magnesium; from 3.66 to 21.21 and 1.89–27.09 for sodium. The accuracy of the method was confirmed by analysis of a certified reference material of spinach leaves (NIST 1570a). The statistical evaluation of the obtained results showed that broccoli samples were not differentiated by city of origin, station, or culture. Nevertheless, by comparing raw and cooked samples, it was noticed a tendency of separation in the principal component analysis and hierarchical cluster analysis.     

Topical Delivery of Fluconazole: In Vitro Skin Penetration and Permeation Using Emulsions as Dosage Forms

ABSTRACT

We investigated in vitro skin penetration and permeation of fluconazole from emulsions containing different penetration enhancers. Fluconazole permeation was high (15–65% of the applied dose) across hairless mouse skin and low (8–9%) across pig ear skin. Permeation across mice skin from a formulation containing propyleneglycol and isopropyl myristate was significantly higher than that observed with the paraffin oil and propyleneglycol or Transcutol® emulsions. With pig skin, the paraffin oil or isopropyl myristate and propyleneglycol emulsions showed similar skin permeation and penetration. However, these emulsions provided epidermal concentrations higher than the minimal inhibitory concentrations for most dermatophytes.     

Influence of procedures and transfer modes in MAG welding in the reduction of deformations on marine structure panels

With the growth of the Brazilian shipbuilding industry, problems from the production processes emerged in the form of distortions and residual stresses. This study researched the influence of welding procedures (sequence, welding direction and reverse pass) and transfer modes (MAG-CC, MAG-STT and MAG-CW) on distortion values. All of the welds were performed with ER70S-6 wire and pure CO₂ shielding gas in the short-circuit mode. It was observed that the most important variable was change of welding direction, which is directly connected to restriction levels of the test panel. The sequences used showed little effect on the distortion values. The reverse pass had low distortion values, yet was unproductive. It was observed that the distortion values were similar for the processes and MAG-STT. The panels welded by the MAG-CW process obtained the lowest distortion values measured.     

BEAN DRYING IN FIXED,SPOUTED AND SPOUT-FLUID BEDS: A COMPARISON AND EMPIRICAL MODELING

ABSTRACT

In this work the drying of IAC-Carioca bean was analyzed experimentally in fixed, spouted and spout-fluid beds. A laboratory scale, batch operated apparatus was used. To obtain experimental data, a factorial design technique was used and the influences of the following variables on the process were evaluated: the solids toad, initial grain moisture and drying air temperature. This analysis was done for each dryer by means of drying curves, evolution of grain temperature over time, drying rate and statistical results obtained from factorial design. An energy evaluation was also done and used as a means of comparison between the dryers studied. The three dryers operating under the same conditions showed very similar behavior and the fixed bed dryer showed a performance slightly better. With this work the potential of using spouted bed grain dryerswas confirmed and the possibility of using the spout-fluid bed as a dryer was verified. Two empirical models were proposed and their parameters were correlated with experimental variables. A sensory evaluation was also performed for the purpose of evaluating the effects that the high drying temperatures had on the grain's potential value as food.