Chlorine dioxide against bacteria and yeasts from the alcoholic fermentation

The ethanol production in Brazil is carried out by fed-batch or continuous process with cell recycle, in such way that bacterial contaminants are also recycled and may be troublesome due to the substrate competition. Addition of sulphuric acid when inoculum cells are washed can control the bacterial growth or alternatively biocides are used. This work aimed to verify the effect of chlorine dioxide, a well-known biocide for bacterial decontamination of water and equipments, against contaminant bacteria ( Bacillus subtilis, Lactobacillus plantarum, Lactobacillus fermentum and Leuconostoc mesenteroides) from alcoholic fermentation, through the method of minimum inhibitory concentration ( MIC), as well as its effect on the industrial yeast inoculum. Lower MIC was found for B. subtilis ( 10 ppm) and Leuconostoc mesenteroides ( 50 ppm) than for Lactobacillus fermentum ( 75 ppm) and Lactobacillus plantarum ( 125 ppm). Additionally, these concentrations of chlorine dioxide had similar effects on bacteria as 3 ppm of Kamoran (R) ( recommended dosage for fermentation tanks), exception for B. subtilis, which could not be controlled at this Kamoran (R) dosage. The growth of industrial yeasts was affected when the concentration of chlorine dioxide was higher than 50 ppm, but the effect was slightly dependent on the type of yeast strain. Smooth yeast colonies ( dispersed cells) seemed to be more sensitive than wrinkled yeast colonies ( clustered cells/pseudohyphal growth), both isolated from an alcohol-producing unit during the 2006/2007 sugar cane harvest. The main advantage in the usage of chlorine dioxide that it can replace antibiotics, avoiding the selection of resistant populations of microorganisms.

Relationship Between Speed and Time in Running

The purpose of this study was to evaluate the effect of using different mathematical models to describe the relationship between treadmill running speed and time to exhaustion. All models generated a value for an aerobic parameter (critical speed; S(critical)). 35 university students performed 5-7 constant-speed 0%-slope treadmill tests at speeds that elicited exhaustion in similar to 3 min to similar to 10 min. Speed and time data were fitted using 3 models: (1) a 2-parameter hyperbolic model; (2) a 3-parameter hyperbolic model; and (3) a hybrid 3-parameter hyperbolic + exponential model. The 2-parameter model generated values for S(critical) (mean (+/- SD): 186 +/- 33 m.min(-1)) and anaerobic distance capacity (ADC; 251 +/- 122 m) with a high level of statistical certainty (i.e., with small SEEs). The 3-parameter models generated parameter estimates that were unrealistic in magnitude and/or associated with large SEEs and little statistical certainty. Therefore, it was concluded that, for the range of exercise durations used in the present study, the 2-parameter model is preferred because it provides a parsimonious description of the relationship between velocity and time to fatigue, and it produces parameters of known physiological significance, with excellent confidence.

Análise não destrutiva de pigmentos fotossintéticos em folhas de gergelim

The study aimed to relate the photosynthetic pigments, which were extracted in a laboratory and the readings were obtained by the portable chlorophyll meter ClorofiLOG 1030, by using mathematical models in sesame leaves. This work was conducted in December 2010, at Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA) Cotton, where feaf discs were removed to measure chlorophyll indexes through the portable chlorophyll meter. The same leaf discs were subjected to extraction of photosynthetic pigments, by using 5 mL dimethyl sulfoxide (DMSO), and were kept in a water bath at 70 degrees C for 30 min. Afterwards, an aliquot of 3 mL was removed to be read in a spectrophotometer at wavelengths of 470, 646 and 663 nm. Based on analytical results, mathematical models were adjusted by using the chlorophyll index to predict the levels of chlorophyll a, b, and total, and of carotenoids and their relationships. The study concluded that the portable chlorophyll meter ClorofiLOG 1030 can be used to estimate the concentration of photosynthetic pigments in sesame leaves with high precision, besides saving resources and time.

TWO DECOMPOSITION APPROACHES APPLIED TO THE MULTI-AREA OPTIMAL REACTIVE POWER FLOW PROBLEM

This paper applies two methods of mathematical decomposition to carry out an optimal reactive power flow (ORPF) in a coordinated decentralized way in the context of an interconnected multi-area power system. The first method is based on an augmented Lagrangian approach using the auxiliary problem principle (APP). The second method uses a decomposition technique based on the Karush-Kuhn-Tucker (KKT) first-order optimality conditions. The viability of each method to be used in the decomposition of multi-area ORPF is studied and the corresponding mathematical models are presented. The IEEE RTS-96, the IEEE 118-bus test systems and a 9-bus didactic system are used in order to show the operation and effectiveness of the decomposition methods.

PRACTICAL LAND GRADING BASED ON LEAST SQUARES.

Practical methods for land grading design of a plane surface for rectangular and irregularly shaped fields based on a least squares analysis are presented. The least squares procedure leads to a system of three linear equations with three unknowns for determination of the best-fit plane. The equations can be solved by determinants (Cramer's rule) using a procedure capable of solution by many programmable calculators. The detailed computational process for determining the equation of the plane and a simple method to find the centroid location of an irregular field are also given. An illustrative example and design instructions are included to demonstrate the application of the design procedure.

Reação metabólica à infecção no hospedeiro.

At the site of local reaction to infection the interleukin-1 (1L-1) is released signaling to distant tissues the presence of infection and attempting to strengthen the host's defenses and inhibit the bacterial growth. This phenomenon is accompanied by anorexia and fever. The muscle-protein breakdown is sustained and the released amino acids are taken up by the liver and other RE structures where they are used as substrates for energy and for synthesis of defense-related proteins. The metabolic adaptations to sepsis include hyperthermia, increased synthesis of hepatic globulins, development of granulopoiesis and neutrophilia and redistribution of serum iron and trace minerals.

Electronic structure of polyacetylene with bonded oxygen

In this work we have studied the electronic structure of finite polyacetylene chains with structural oxygen-bonding models following data from 13C-NMR experiments. We have used a combination of Austin Method One and Hydrogenic Atoms in Molecules version 3 methods to perform geometric and spectroscopic calculations. Our results show that the electronically-active states are generally unaffected by the incorporation of oxygen. © 1992.

Thermoeconomic functional analysis applied in cogeneration systems associated to cellulose plants

Thermoeconomic Functional Analysis is a method developed for the analysis and optimal design of improvement of thermal systems (Frangopoulos, 1984). The purpose of this work is to discuss the cogeneration system optimization using a condensing steam turbine with two extractions. This cogeneration system is a rational alternative in pulp and paper plants in regard to the Brazilian conditions. The objective of this optimization consists of minimizing the global cost of the system acquisition and operation, based on the parametrization of actual data from a cellulose plant with a daily production of 1000 tons. Among the several possible decision variables, the pressure and temperature of live steam were selected. These variables significantly affect the energy performance of the cogeneration system. The conditions which determine a lower cost for the system are presented in conclusion.

Static converter: didactic support software

Teaching a course of special electric loads in a continuing education program to power engineers is a difficult task because they are not familiarized with switching topology circuits. Normally, in a typical program, many hours are dedicated to explain the thyristors switching sequence and to draw the converter currents and terminal voltages waveforms for different operative conditions. This work presents teaching support software in order to optimize the time spent in this task and, mainly to benefit the assimilation of the proposed subjects, studying the static converter under different non-ideal operative conditions.

Anomalous flow behaviour of bauxite tailings

This paper deals with the anomalous flow behaviour observed in two bauxite tailings pumping systems, with 450 mm and 680 mm outer diameter. In order to enlarge the pipeline lengths in the field, tests were carried out in a laboratory test-loop in order to try to understand the anomalous (intermittent) flow behaviour and to solve the problem. Based on data obtained from these laboratory tests and using a generalized REYNOLDS number it was possible to obtain results that fit the MOODY ROUSE diagram.

The stability of the Johnson-Mehl-Avrami equation parameters

The stability of the parameters of the Johnson-Mehl-Avrami equation was studied using two parametrizations of the sigmoidal function and its fit to some kinetic data. The results indicate that one of the forms of the function has more stable parameters and only for this form it is reasonable to use, as an approximation, the linear regression theory to analyse the parameters. © 1995 Chapman & Hall.

Optical transition probabilities and compositional dependence of Judd-Ofelt parameters of Er3+ ions in fluoroindate glass

Fluoroindate glasses containing 1, 2, 3, and 4 mol% ErF3 were prepared in a dry box under an argon atmosphere. Absorption spectra of these glasses at room temperature were obtained. The Judd-Ofelt parameters Ωλ (λ = 2, 4, 6) for f-f transitions of Er3+ ions as well as transition probabilities, branching ratios, radiative lifetimes, and peak cross-sections for stimulated emission of each band were determined. The concentration effect on the intensities is analyzed. The optical properties of the fluoroindate glasses doped with Er3+ ions are compared with those of other glasses described in the literature. © 1995.

Modelling of the influence of the layer pollution thickness in high voltage polluted insulators

An experimental model and a mathematical model with the introduction of a ramp in the channel of Obenaus model are presented. The aim is to present a better reproduction of the real layer pollution deposited on the HV insulators. This better reproduction is obtained from two types of thickness variation: the introduction of a ramp (soft variation) and the introduction of a step (sudden variation). The computational simulations and the experimental data suggest that the introduction of the ramp is the better reproduction of the layer pollution. The ramp approximates to the real layer pollution more than the step.

Image registration and image interpolation in volume rendering of cross sections

We outline a method for registration of images of cross sections using the concepts of The Generalized Hough Transform (GHT). The approach may be useful in situations where automation should be a concern. To overcome known problems of noise of traditional GHT we have implemented a slight modified version of the basic algorithm. The modification consists of eliminating points of no interest in the process before the application of the accumulation step of the algorithm. This procedure minimizes the amount of accumulation points while reducing the probability of appearing of spurious peaks. Also, we apply image warping techniques to interpolate images among cross sections. This is needed where the distance of samples between sections is too large. Then it is suggested that the step of registration with GHT can help the interpolation automation by simplifying the correspondence between points of images. Some results are shown.

Asymmetrical magnetization in three-phase core type transformers

The performance of the three-phase core type transformers, under AC/DC double excitation is discussed in this work. It is presented a mathematical model that considers the mutual coupling between phases and the magnetic nonlinearity. The validity of the proposed model is verified by means of the experimental and simulated results.