Ultrasonic Viscosity Measurement Using the Shear-Wave Reflection Coefficient with a Novel Signal Processing Technique

Real-time viscosity measurement remains a necessity for highly automated industry. To resolve this problem, many studies have been carried out using an ultrasonic shear wave reflectance method. This method is based on the determination of the complex reflection coefficient`s magnitude and phase at the solid-liquid interface. Although magnitude is a stable quantity and its measurement is relatively simple and precise, phase measurement is a difficult task because of strong temperature dependence. A simplified method that uses only the magnitude of the reflection coefficient and that is valid under the Newtonian regimen has been proposed by some authors, but the obtained viscosity values do not match conventional viscometry measurements. In this work, a mode conversion measurement cell was used to measure glycerin viscosity as a function of temperature (15 to 25 degrees C) and corn syrup-water mixtures as a function of concentration (70 to 100 wt% of corn syrup). Tests were carried out at 1 MHz. A novel signal processing technique that calculates the reflection coefficient magnitude in a frequency band, instead of a single frequency, was studied. The effects of the bandwidth on magnitude and viscosity were analyzed and the results were compared with the values predicted by the Newtonian liquid model. The frequency band technique improved the magnitude results. The obtained viscosity values came close to those measured by the rotational viscometer with percentage errors up to 14%, whereas errors up to 96% were found for the single frequency method.

Assembling a consistent set of sentences in relational probabilistic logic with stochastic independence

We examine the representation of judgements of stochastic independence in probabilistic logics. We focus on a relational logic where (i) judgements of stochastic independence are encoded by directed acyclic graphs, and (ii) probabilistic assessments are flexible in the sense that they are not required to specify a single probability measure. We discuss issues of knowledge representation and inference that arise from our particular combination of graphs, stochastic independence, logical formulas and probabilistic assessments. (C) 2007 Elsevier B.V. All rights reserved.

Topology Optimized Design, Microfabrication and Characterization of Electro-Thermally Driven Microgripper

This article presents a systematic and logical study of the topology optimized design, microfabrication, and static/dynamic performance characterization of an electro-thermo-mechanical microgripper. The microgripper is designed using a topology optimization algorithm based on a spatial filtering technique and considering different penalization coefficients for different material properties during the optimization cycle. The microgripper design has a symmetric monolithic 2D structure which consists of a complex combination of rigid links integrating both the actuating and gripping mechanisms. The numerical simulation is performed by studying the effects of convective heat transfer, thermal boundary conditions at the fixed anchors, and microgripper performance considering temperature-dependent and independent material properties. The microgripper is fabricated from a 25 mm thick nickel foil using laser microfabrication technology and its static/dynamic performance is experimentally evaluated. The static and dynamic electro-mechanical characteristics are analyzed as step response functions with respect to tweezing/actuating displacements, applied current/power, and actual electric resistance. A microgripper prototype having overall dimensions of 1mm (L) X 2.5mm (W) is able to deliver the maximum tweezing and actuating displacements of 25.5 mm and 33.2 mm along X and Y axes, respectively, under an applied power of 2.32 W. Experimental performance is compared with finite element modeling simulation results.

Modeling extended Petri nets compatible with GHENeSys IEC61131 for industrial automation

Petri net (PN) modeling is one of the most used formal methods in the automation applications field, together with programmable logic controllers (PLCs). Therefore, the creation of a modeling methodology for PNs compatible with the IEC61131 standard is a necessity of automation specialists. Different works dealing with this subject have been carried out; they are presented in the first part of this paper [Frey (2000a, 2000b); Peng and Zhou (IEEE Trans Syst Man Cybern, Part C Appl Rev 34(4):523-531, 2004); Uzam and Jones (Int J Adv Manuf Technol 14(10):716-728, 1998)], but they do not present a completely compatible methodology with this standard. At the same time, they do not maintain the simplicity required for such applications, nor the use of all-graphical and all-mathematical ordinary Petri net (OPN) tools to facilitate model verification and validation. The proposal presented here completes these requirements. Educational applications at the USP and UEA (Brazil) and the UO (Cuba), as well as industrial applications in Brazil and Cuba, have already been carried out with good results.

Reconfigurable organisation to cope with unpredictable goals

The paper proposes a methodology and design rules for organisational structures facing higher necessity of rapidly reconfigure themselves to cope with unpredictable situations-new markets, new products, changing mix of production, problems in production process or flows etc. It implies changing and often conflictive criteria for production goals and for the allocation of work. The methodology was developed based on a large field action research and consulting. Their basis is the design of auto-reconfigurable working groups-or groups with variable geometry, depending on the events to face. (C) 2009 Elsevier B.V. All rights reserved.

A calibration approach based on Takagi-Sugeno fuzzy inference system for digital electronic compasses

Recently, the development of industrial processes brought on the outbreak of technologically complex systems. This development generated the necessity of research relative to the mathematical techniques that have the capacity to deal with project complexities and validation. Fuzzy models have been receiving particular attention in the area of nonlinear systems identification and analysis due to it is capacity to approximate nonlinear behavior and deal with uncertainty. A fuzzy rule-based model suitable for the approximation of many systems and functions is the Takagi-Sugeno (TS) fuzzy model. IS fuzzy models are nonlinear systems described by a set of if then rules which gives local linear representations of an underlying system. Such models can approximate a wide class of nonlinear systems. In this paper a performance analysis of a system based on IS fuzzy inference system for the calibration of electronic compass devices is considered. The contribution of the evaluated IS fuzzy inference system is to reduce the error obtained in data acquisition from a digital electronic compass. For the reliable operation of the TS fuzzy inference system, adequate error measurements must be taken. The error noise must be filtered before the application of the IS fuzzy inference system. The proposed method demonstrated an effectiveness of 57% at reducing the total error based on considered tests. (C) 2011 Elsevier Ltd. All rights reserved.

Supercritical steam cycles and biomass integrated gasification combined cycles for sugarcane mills

Back in 1970s and 1980s, cogeneration plants in sugarcane mills were primarily designed to consume all bagasse, and produce steam and electricity to the process. The plants used medium pressure steam boilers (21 bar and 300 degrees C) and backpressure steam turbines. Some plants needed also an additional fuel, as the boilers were very inefficient. In those times, sugarcane bagasse did not have an economic value, and it was considered a problem by most mills. During the 1990s and the beginning of the 2000s, sugarcane industry faced an open market perspective, thus, there was a great necessity to reduce costs in the production processes. In addition, the economic value of by-products (bagasse, molasses, etc.) increased, and there was a possibility of selling electricity to the grid. This new scenario led to a search for more advanced cogeneration systems, based mainly on higher steam parameters (40-80 bar and 400-500 degrees C). In the future, some authors suggest that biomass integrated gasification combined cycles are the best alternative to cogeneration plants in sugarcane mills. These systems might attain 35-40% efficiency for the power conversion. However, supercritical steam cycles might also attain these efficiency values, what makes them an alternative to gasification-based systems. This paper presents a comparative thermoeconomic study of these systems for sugarcane mills. The configurations studied are based on real systems that could be adapted to biomass use. Different steam consumptions in the process are considered, in order to better integrate these configurations in the mill. (C) 2009 Elsevier Ltd. All rights reserved.

Horticultural performance of `Folha Murcha` sweet orange onto twelve rootstocks

Despite its outstanding position, the Brazilian citriculture is established on a very limited pool of varieties that limits its expansion and restricts the fruit availability throughout the year. This situation determines the urgent necessity of developing alternative scion and rootstock cultivars, with good performance under local conditions. `Folha Murcha` sweet orange (Citrus sinensis (L.) Osbeck) is a late-harvest cultivar, suitable both for the juice processing industry and the fresh fruit market, being described as tolerant to citrus canker (Xanthomonas citri subsp. citri Schaad et al.), and less affected by citrus variegated chlorosis (Xylella fastidiosa Wells et al.). A study was conducted in Bebedouro, Sao Paulo State, Brazil, to evaluate the horticultural performance of `Folha Murcha` sweet orange budded onto 12 rootstocks: the citrandarin `Changsha` mandarin (Citrus reticulata Blanco) x Poncirus trifoliata `English Small`: the hybrid `Rangpur` lime (Citrus limonia Osbeck) x `Swingle` citrumelo (P. trifoliata (L.) Raf x Citrus paradisi Macfad.); the trifoliates (P. trifoliata (L.) Raf.)`Rubidoux`, `FCAV`, and `Flying Dragon` (P. trifoliata var. monstrosa); the `Sun Chu Sha Kat` mandarin (C. reticulata Blanco); the `Sunki` mandarin (Citrus sunki (Hayata) Hart. ex. Tanaka); the `Rangpur` limes (C. limonia Osbeck) `Cravo Limeira` and `Cravo FCAV`; `Carrizo` citrange (C. sinensis x P. trifoliata), `Swingle` citrumelo (P. trifoliata x C. paradisi), and `Orlando` tangelo (C. paradisi x Citrus tangerina cv. `Dancy`). The experimental grove was planted in 2001, using a 7 m x 4 m spacing, in a randomized block design, with five replications and two plants per plot. No supplementary irrigation was applied. Fruit yield, canopy volume, tree tolerance to drought and to citrus variegated chlorosis, and fruit quality were assessed for each rootstock. Trees grafted onto the `Flying Dragon` trifoliate were smaller in size, but had largest yield efficiency when compared to those grafted onto other rootstocks. Lower alternate bearing index was observed on trees budded onto `Cravo FCAV` `Rangpur` lime. Both `Rangpur` lime rootstocks and the `Sunki` mandarin induced higher tree tolerance to drought. The `Flying Dragon` trifoliate induced better fruit quality and higher tolerance to citrus variegated chlorosis (CVC) to `Folha Murcha` trees. A cluster multivariate analysis identified three groups of rootstocks with similar effects on `Folha Murcha` tree performance. Among the 12 evaluated rootstocks, the `Flying Dragon` trifoliate has a unique effect on plant growth, tolerance to drought and CVC, fruit yield and fruit quality of `Folha Murcha` trees, and may be better suited for high-density plantings. (C) 2011 Elsevier B.V. All rights reserved.

Development of Vegetable Oil Emulsions with Lamellar Liquid-Crystalline Structures

Emulsions containing vegetable oils and anisotropic phases have especially attractive properties in pharmaceutical technology. They are use as vehicle for different kind of drugs, especially those of topical application. Apart from that, many vegetable oil have pharmacological activity, increasing the necessity for the development of new delivery systems for them. We developed emulsions with vegetable oils at a fixed surfactant ratio and observed the formation of liquid crystalline phases. Nine vegetable oils: Andiroba, Apricot, Avocado, Brazil Nut, Buriti, Cupuassu, Marigold, Passion Fruit and Pequi and mineral oil were tested. Surfactant system was consisted by Steareth-2 and Ceteareth-5. Emulsions were prepared by the emulsion phase inversion (EPI) method, presenting high stability independent on the HLB value. Results indicate that this method could be employed to attain stable emulsions, even if the required HLB value is not known.

Methylmercury and inorganic mercury determination in blood by using liquid chromatography with inductively coupled plasma mass spectrometry and a fast sample preparation procedure

Despite the necessity to differentiate chemical species of mercury in clinical specimens, there area limited number of methods for this purpose. Then, this paper describes a simple method for the determination of methylmercury and inorganic mercury in blood by using liquid chromatography with inductively coupled mass spectrometry (LC-ICP-MS) and a fast sample preparation procedure. Prior to analysis, blood (250 mu L) is accurately weighed into 15-mL conical tubes. Then, an extractant solution containing mercaptoethanol, L-cysteine and HCI was added to the samples following sonication for 15 min. Quantitative mercury extraction was achieved with the proposed procedure. Separation of mercury species was accomplished in less than 5 min on a C18 reverse-phase column with a mobile phase containing 0.05% (v/v) mercaptoethanol, 0.4% (m/v) L-cysteine, 0.06 mol L(-1) ammonium acetate and 5% (v/v) methanol. The method detection limits were found to be 0.25 mu g L(-1) and 0.1 mu Lg L(-1) for inorganic mercury and methylmercury, respectively. Method accuracy is traceable to Standard Reference Material (SRM) 966 Toxic Metals in Bovine Blood from the National Institute of Standards and Technology (NIST). The proposed method was also applied to the speciation of mercury in blood samples collected from fish-eating communities and from rats exposed to thimerosal. With the proposed method there is a considerable reduction of the time of sample preparation prior to speciation of Hg by LC-ICP-MS. Finally, after the application of the proposed method, we demonstrated an interesting in vivo ethylmercury conversion to inorganic mercury. (C) 2009 Elsevier B.V. All rights reserved.

Lead in saliva from lead-exposed and unexposed children

Introduction: Whole blood is used for diagnosis of lead exposure. A non-invasive method to obtain samples for the biomonitoring of lead contamination has become a necessity. This study 1) compares the lead content in whole saliva samples (Pb-saliva) of children from a city with no reported lead contamination (Ribeirao Preto, Sao Paulo State, Brazil) and children of a region notoriously contaminated with lead (Bauru, Sao Paulo State, Brazil), and 2) correlates Pb-saliva with the lead content in the enamel microbiopsy samples (Pb-enamel) in the case of these two populations. Methods: From a population of our previous study that had included 247 children (4- to 6-year-old) from Ribeirao Preto, and 26 children from Bauru, Pb-saliva was analyzed in 125 children from Ribeirdo Preto and 19 children from Bauru by inductively coupled plasma mass spectrometry (ICPMS). To correlate Pb-saliva with Pb-enamel, we used Pb-enamel data obtained in our previous study. The Mann-Whitney test was employed to compare the Pb-saliva data of the two cities. Pb-saliva and Pb-enamel values were then Log(10) transformed to normalize data, and Pb-saliva and Pb-enamel were correlated using Pearson`s correlation coefficient. Results: Median Pb-saliva from the Ribeirao Preto population (1.64 mu g/L) and the Bauru population (5.85 mu g/L) were statistically different (p<0.0001). Pearson`s correlation coefficient for Log(10) Pb-saliva versus Log(10) Pb-enamel was 0.15 (p=0.08) for Ribeirao Preto and 0.38 (p=0.11) for Bauru. Conclusions: A clear relationship between Pb-saliva and environmental contamination by lead is shown. Further studies on Pb-saliva should be undertaken to elucidate the usefulness of saliva as a biomarker of lead exposure, particularly in children. (C) 2008 Elsevier B.V. All rights reserved.

Evaluation of curcumin and cisplatin-induced DNA damage in PC12 cells by the alkaline comet assay

A very appropriate method for antigenotoxicity evaluation of antioxidants is the comet assay, since this analytical method detects initial DNA lesions that are still subject to repair; in other words, lesions that are very associated to damages resulting from the generation and subsequent action of reactive species. However, a solid evaluation should be developed in order to avoid inexact interpretations. In our study, besides the association of curcumin with cisplatin, curcumin and cisplatin agents were also tested separately. Classical genotoxic compounds, when tested by the comet assay, present an increase in the nucleoid tail; however, the cisplatin treatment has resulted in a decrease of DNA migration. This was an expected effect, as the cross-links between cisplatin and DNA decrease the DNA electrophoretic mobility. A similar effect was observed with the curcumin treatment, which decreased the nucleoid tail. Such effect was not expected and reinforced the necessity of including in the study, separate treatment groups with potentially antigenotoxic substances. The comet assay results have been analyzed using specific software for image analysis, as well as the classical visual analysis, and we have observed that the effect of decrease in DNA electrophoretic mobility was more easily observed when the data were analyzed by the software.

von Wright`s Therapy to Jorgensen`s Syndrome

In his last papers about deontic logic, von Wright sustained that there is no genuine logic of norms. We argue in this paper that this striking statement by the father of deontic logic should not be understood as a death sentence to the subject. Rather, it indicates a profound change in von Wright`s understanding about the epistemic and ontological role of logic in the field of norms. Instead of a logical constructivism of deontic systems revealing a necessary structure of prescriptive discourse, which marked his earlier efforts, he adopted the view that such systems should be seem as mere objects of comparison, i.e. as providing practical standards of rationality for norm-giving activity. Within such view he proposed an interpretation of standard deontic logic in such a way to free deontic logicians from the philosophical difficulties related to the so-called Jorgensen`s dilemma and deontic paradoxes. This effort, as we claim in the present paper, is an application of Wittgenstein`s therapeutic method to dissolve philosophical difficulties caused by the use of logical tools to model relations between norms.

Information Society, Teaching, and Learning: Education Reforms in Brazil

This article examines the subject matter of learning within the context of information society, through an inquiry concerning both the reforms in education adopted in Brazil in the last thirty years and their results. It provides a revision on the explanations of school failure based on assumptions of learning problems due to cognitive and linguistic deficits. From the guidelines related with written school forms as well as the constant cultural oppression accomplished inside the school, the article claims the necessity of changing the psychological and pedagogic views that, under the label of democratic practices, determine school institutions and its daily life, by means of instrumental relations with knowledge that disregard the reading practices which are congenial to popular culture.

The perception of Executives and other Employees on the answer to the Sarbanes-Oxley: case study of a subsidary of the American auto industry established in Brazil

To attend and obtain the systems and. internal controls mechanisms proposed by Sarbanes-Oxley certifications is actually a big challenge,for most of the multinational companies registered in SEC (US Securities and Exchange Commission). This work has the objective of contributing to the analysis of this methodology, not only to attend the law but to reduce cost and generate value through the strengthen of the internal control systems, turning them into animating value generation process mechanisms. So, the idea is to identify the main gaps in the theory through the literature revision and a case study in order to put a question to the main deficiencies, strong points or contributions through the evaluation of the noticed practices. Finally, we can say that a a result of the research and the analyses made in. this case, the vast majority of executives and other employees recognize the benefit that Sarbanes-Oxley Act has brought to the company searched. Also recognize that, although there is still necessity for systemic adequacy and infrastructure, it helps and reinforce reducing and controlling the risks. the system of internal controls in all areas of expertise. They approach and understand that there is the need for a change in the other employees` culture to be inserted in the day-today routine as internal controls, attention to Sarbanes-Oxley and Corporate Governance, making the control cost smaller when compared to the benefits generated.