Leak detection in petroleum pipelines using a fuzzy system

A methodology for pipeline leakage detection using a combination of clustering and classification tools for fault detection is presented here. A fuzzy system is used to classify the running mode and identify the operational and process transients. The relationship between these transients and the mass balance deviation are discussed. This strategy allows for better identification of the leakage because the thresholds are adjusted by the fuzzy system as a function of the running mode and the classified transient level. The fuzzy system is initially off-line trained with a modified data set including simulated leakages. The methodology is applied to a small-scale LPG pipeline monitoring case where portability, robustness and reliability are amongst the most important criteria for the detection system. The results are very encouraging with relatively low levels of false alarms, obtaining increased leakage detection with low computational costs.     

Immobilization of zirconocene within silica–tungsten by entrapment: Tuning electronic effects of the support on the supported complex

The immobilization of Cp₂ZrCl₂ was performed by entrapment within the binary oxide SiO₂–WO₃ using a non-hydrolytic sol–gel route. The catalyst and oxide matrix were characterized by complementary techniques (Rutherford backscattering spectrometry, ultraviolet–visible diffuse reflectance and infrared transmission spectroscopy, differential pulse voltammetry, adsorption–desorption of N₂, and X-ray diffraction). The catalyst performance in terms of catalytic activity and polymer properties was evaluated by ethylene polymerization. Catalyst characterization suggested that the entrapped complex exhibited lower Zr electronic density than the corresponding unsupported metallocene. The polymerization results also revealed that this low Zr electronic density is optimized in terms of complex activation with low MAO concentration (low [Al/Zr] ratio) and reactivity. This fine tuning results in a catalyst system that is active with a low [Al/Zr] ratio and that achieves high catalytic activity. The results demonstrate that the entrapping method allows the generation of a catalyst system in which part of the activation process is attributed to the support. In this sense, the support may partially play MAO functions by stabilizing the active catalytic species.     

Antiangiogenic properties of carotenoids: A potential role of maize as functional food

Several human disorders are associated with neovascularization. The current in vivo study examines the effect in the blood vessel formation of a xanthophyll-rich seed extract of maize. The angiostatic effects of treatment with maize seed carotenoid extract (0.1–10 μM of zeaxanthin equivalent/implant) were evaluated in the chick yolk sac membrane (YSM) (12–50% inhibition, P < 0.05) as well as in the chorioallantoic membrane (CAM) assay (23–52% inhibition, P < 0.05) as compared to control group. A similar inhibitory action was found by treatments with the retinoic acid (10 μM/embryo, 49% and 57% inhibition) and commercial lutein (10 μM/embryo, 65% and 55% inhibition) (positive controls) performed in the YSM and CAM, respectively. Results point to maize seeds as interesting sources of xanthophylls which effectively inhibited the process of vessel formation, suggesting a potential role of such compounds in the prevention of diseases associated with vascular dysfunction.     

Bayesian estimation of thermophysical parameters of thin metal films heated by fast laser pulses

In this paper, we apply the Markov Chain Monte Carlo method, within the Bayesian framework, for the estimation of parameters appearing in the heat conduction model in metals under the condition of thermal non-equilibrium between electrons and lattice. Such non-equilibrium can be experimentally observed in a time scale of up to few picoseconds, during the heating of thin metal films with laser pulses of the order of femtoseconds. Simulated measurements containing random errors are used for the solution of the inverse problem. Results are presented for the simultaneous estimation of the electron–phonon coupling factor, the thermal conductivity and the heat capacity of the electron gas.     

Developing competition while building up the infrastructure of the Brazilian gas industry

For the last 20 years, countless countries have been carrying out structural reforms in the natural gas industry, trying to achieve efficiency and economic rationality with the introduction of competition. The objective of the paper is to present an approach to the development of competition and infrastructure of the Brazilian natural gas industry. This approach is based on a market projection to 2011, on the international experience and on the characteristics of the Brazilian market, infrastructure and regulatory framework. Possible impacts of the proposed measures are also provided. According to the market projection carried out in this paper, in 2011 there will be a possible surplus of natural gas in the country, which includes a dependence diminishing of the Bolivian gas supply. This gas surplus, allied to an upcoming Gas Law and the trade liberalization in the states of São Paulo and Rio de Janeiro, can stimulate the development of competition, if some changes that proposed in this paper are made in the current Gas Bills. The approach proposed herein seeks to stimulate non-discriminatory open access, focused on information transparency and tariff regulation to help the development of infrastructure and competition.     

Physicochemical,biochemical, microbiological and safety aspects of Pico cheese: Assessment throughout maturation and on the final product

Pico cheese is a traditional variety manufactured on the eponymous Azorean Island (Portugal). In total, 153 cheeses were analysed. The average total solids (TS) content by the end of maturation was 63.3 ± 0.3 g/100 g, A_w 0.943–0.966, salt‐in‐moisture 2.12–4.17 g/100 g and pH 4.89–5.11 ± 0.02. Proteolysis was similar to that of other Iberian raw milk cheeses, but the free fatty acid content was generally higher. Lactococci were the predominant bacteria. Coagulase‐positive staphylococci constituted the most severe hygiene problem. Positive correlations were found between maturation time and TS, titratable acidity, A_w, proteolysis indices and Enterobacteriaceae and coagulase‐positive staphylococcus viable numbers.     

Decentralized decision-making and capacitated facility location

Given a set of candidate sites, the capacitated location problem consists of finding a most economical subset of facilities to be located. This paper works with aweak formulation of the problem, having in mind the application in an economic sector with partially decentralized decision-making. The model considers the activities of production, transportation and export, looking for facility locations and distribution alternatives that satisfy the domestic demands, while minimizing the total cost. We have shown improved criteria to locate facilities, assured their optimality and given computational results. We introduce clear economic interpretation of such criteria for the decentralized behavior of the production and distribution agents, based on a pricing system associated with dual variables. Some insight is also given on the possibility of analyzing a location algorithm as a competitive and adaptive process of searching for maximal profit. Within such context, an attempt is made to define the role of government in handling the indivisibility of the production resources, in order to assure stability at an optimal solution.     

A closed-loop mechanical ventilation controller with explicit objective functions

A closed-loop lung ventilation controller was designed, aiming to: 1) track a desired end-tidal CO2 pressure (Pet CO2), 2) find the positive end-expiratory pressure (PEEP) of minimum estimated respiratory system elastance (Ers,e), and 3) follow objective functions conjectured to reduce lung injury. After numerical simulations, tests were performed in six paralyzed piglets. Respiratory mechanics parameters were estimated by the recursive least squares (RLS) method. The controller incorporated a modified PI controller for Pet CO2 and a gradient descent method for PEEP. In each animal, three automated PEEP control runs were performed, as well as a manual PEEP titration of Ers,e and a multiple PetCO2 step change trial. Overall performance indexes were obtained from PEEP control, such as minimum Ers,e (37.0 +/- 4.5 cmH2O x L(-1)), time to reach the minimum Ers,e (235 +/- 182 s) and associated PEEP (6.5 +/- 1.0 cmH2O), and from Pet CO2 control, such as rise time (53 +/- 22 s), absolute overshoot/undershoot of PetCO2 (3 +/- 1 mmHg), and settling time (145 +/- 72 s). The resulting CO2 controller dynamics approximate physiological responses, and results from PEEP control were similar to those obtained by manual titration. Multiple dependencies linking the involved variables are discussed. The present controller can help to implement and evaluate objective functions that meet clinical goals.     

A methodology aimed at better integration of functional verification and RTL design

The advent of new 65 nm/90 nm VLSI technology and SoC design methodologies has brought an explosive growth in the complexity of modern electronic circuits. As a result, functional verification has become the major bottleneck in any digital design flow. Thus, new methods for easier, faster and more reusable verification are required. This paper proposes a verification methodology (VeriSC2) that guides the implementation of working testbenches during hierarchical decomposition and refinement of the design, even before the RTL implementation starts. This approach uses the SystemC Verification Library (SCV), in a tool capable of automatically generating testbench templates. A case study from a MPEG-4 decoder design is used to show the effectiveness of this approach.