Cogeneration in a solid-wastes power-station: a case-study

Nowadays, natural gas is viewed as the solution to the problem of energy supply for Latin America, Europe and North America for the next few decades; Brazil is increasingly becoming dependent upon the Bolivian natural-gas supply - many industries and some entrepreneurs are deciding to construct industrial cogeneration systems and new thermal power-stations burning natural gas because of its low environmental impact and attractive price. However, natural gas is a finite resource: this will cause, in the future, an increase of its unit price. This paper details questions involved in the energy generation and presents solid-waste burning as a possible alternative fuel for the future, especially in the context of cogeneration practice in which the thermal and electric energy are used primarily for the industries located in an industrial district. Two cogeneration schemes are proposed for the burning of municipal solid wastes, associated or not with natural gas, and their technical and economic feasibilities are examined. (C) 1999 Elsevier B.V. Ltd. All rights reserved.

Colorimetric determination of ammonia in air using a hanging drop

A simple and sensitive method for determining atmospheric ammonia (NH3), using a hanging drop, is described. A colorimetric sensor is composed of two optical fibers and the source of monochromatic light implemented was a red light emitting diode (LED) (635 nm). Preliminary experiments were carried out in order to optimize the geometry of the sensor. These tests showed that the best signal absorbance was obtained using a 22 muL deionized water drop for sampling the gas and as addition of 4 muL of each of the reactants to form the blue dye (indophenol). Some important analytical parameters were also studied, including sampling time and flow rate. The analytical curve was constructed with a concentration range of 3-20 ppbv of gaseous NH3 standard. The detection limit reached was of ca 0.5 ppbv. It was observed that formaldehyde and diethylamine did not interfere. However, studies showed that hydrogen sulfide caused a negative interference of 20%, when present in the atmosphere in a concentration equal to that of NE3. The method considered here was shown to be easy to apply, making it possible to make a determination every 17 min.

THE FLUID SYSTEMS FOR THE SLD CHERENKOV RING IMAGING DETECTOR

We describe the design and operation of the fluid delivery, monitor and control systems for the SLD barrel Cherenkov Ring Imaging Detector (CRID). The systems deliver drift gas (C2H6+TMAE), radiator gas (C5F12+N2) and radiator liquid (C6F14). MeasUred critical quantities such as electron lifetime in the drift gas and ultra-violet (UV) transparencies of the radiator fluids, together with the operational experience, are also reported.

Direct analysis of biodiesel microemulsions using an inductively coupled plasma mass spectrometry

An analytical procedure for direct introduction of biodiesel samples into an inductively coupled plasma mass spectrometer (ICP-MS) by using microemulsion for sample preparation was developed here. Cadmium, Co, Cu, Mn, Ni, Pb, Ti, and Zn were determined in biodiesel microemulsified samples prepared from different oleaginous sources (African palm, castor beans, palm, soybeans and an unknown oleaginous). Microemulsions were prepared using 0.25 mL Triton X-100, 0.25 mL 20% v v(-1) HNO(3), 0.50 mL biodiesel sample and 4.0 mL n-propanol. Argon-oxygen mixture was added to the plasma as auxiliary gas for correcting matrix effects caused by the high carbon load due to biodiesel microemulsions. The oxygen gas flow rate was set in 37.5 mL min(-1). The accuracy of the developed procedure was evaluated by applying addition-recovery experiments for biodiesel samples from different sources. Recoveries varied from 76.5 to 116.2% for all analytes but Zn in castor beans biodiesel sample (65.0 to 76.2%). Recoveries lower than 86.6% were obtained for palm biodiesel sample, probably due to matrix effects. Detection limits calculated by using oxygen in the composition of the auxiliary gas added to the plasma were higher than those calculated without using it, probably due to the highest formation of oxides. Despite oxides formation, best analytical performance was reached by using oxygen as auxiliary gas and by proper correction of transport interferences. The developed procedure based on microemulsion formation was suitable for direct introduction of biodiesel samples in ICP-MS. (C) 2010 Elsevier B.V. All rights reserved.

Fadiga de grampos de retenção em prótese parcial removível. Efeito de ligas, espessuras e técnicas de fusão. Parte I.

The authors looked for the verification of the fatigue of retentive clasps utilized on the removable partial denture. According to this, it was idealized and built on assay machine, that through movements, simulate the insertion and removal of the clasp for a pattern tooth, manufactured on cobalt-chromium which has all the preparation normally utilized to the correct confection of this type of prosthesis. It was utilized three different commercial alloys based on cobalt-chromium: L1-Biosil; L2-Steldent; L3-Duracron. It was utilized the T clasp of Roach, with was tested upon three different proportions among width and thickness: E1-1.7;E2-2.0 and E3-2.3 and was casted through two casting techniques: F1-oxygen-gas and F2-oxygen-acetylene. The clasps were tested on the machine, which allowed the reading of the number of insertion and removal cycles made until fatigue appeared. The obtained results were submitted to the statistic analysis and the authors concluded that: a) L3 (Duracrom) obtained the best results followed by L1 (Biosil) and finally L3 (Steldent); b) among the analyzed thickness, the best results were obtained by E3, followed by E2 and after this E1; c) form the casting techniques, F2 gave us the best results.

Fadiga de grampos de retenção em prótese parcial removível. Efeito de ligas, espessuras e técnicas de fusão. Parte II.

The authors tested the T clasp of Roach in three differents proportions among width and thickness: E1-1.7; E2-2.0 and E3-2.3, with a constant length of 15 mm. These clasps were casted with three cobalt-chromium alloys (L1-Biosil; L2-Steldent and L3-Duracrom), through two casting techniques (F1-oxygen-gas and F2-oxygen-acetylene). The fatigue of the clasps were verified by using and assay machine, that through movements, simulate the insertion and removal of the clasps for a pattern which were obtained from a premolar, prepared in a surveyor. This machine detect the fatigue of the clasps and count the number of cycles of insertion and removal realized. The obtained results of the interaction between the analysed factors, were submitted to the statistic analysis and the authors concluded that: a) the interaction of factors, Alloy x Thickness, Alloy x Casting Technique and Thickness x Casting Technique did not change the order of effects that the factors showed separately but gave rise to effects of different magnitude for any observed sense; b) the simultaneous interaction of the factors Alloy x Thickness x Casting Technique confirmed the superiority of the L3 alloy, the thickness E3 and the F2 casting technique.

Indoor radon measurements in six Latin American countries

Most of the natural radiation dose to man comes from radon gas and its progeny. Several countries have established national institutions and national programs in charge of the study of radon and its connection with lung cancer risk and public health. In this paper an indoor radon measurements in Latin American countries is presented. The participants in this work were from Argentina, Brazil, Ecuador, Mexico, Peru and Venezuela. Many different techniques are used in this common effort, and the indoor radon levels in specific locations in each of the participant countries are presented.

Effects of contrast material on computed tomographic measurements of lung volumes in patients with acute lung injury

Background. Intravenous injection of contrast material is routinely performed in order to differentiate nonaerated lung parenchyma from pleural effusion in critically ill patients undergoing thoracic computed tomography (CT). The aim of the present study was to evaluate the effects of contrast material on CT measurement of lung volumes in 14 patients with acute lung injury. Method. A spiral thoracic CT scan, consisting of contiguous axial sections of 10 mm thickness, was performed from the apex to the diaphragm at end-expiration both before and 30 s (group 1; n=7) or 15 min (group 2; n=7) after injection of 80 ml contrast material. Volumes of gas and tissue, and volumic distribution of CT attenuations were measured before and after injection using specially designed software (Lungview®; Institut National des Télécommunications, Evry, France). The maximal artifactual increase in lung tissue resulting from a hypothetical leakage within the lung of the 80 ml contrast material was calculated. Results. Injection of contrast material significantly increased the apparent volume of lung tissue by 83 ± 57 ml in group 1 and 102 ± 80 ml in group 2, whereas the corresponding maximal artifactual increases in lung tissue were 42 ± 52 ml and 31 ± 18 ml. Conclusion. Because systematic injection of contrast material increases the amount of extravascular lung water in patients with acute lung injury, it seems prudent to avoid this procedure in critically ill patients undergoing a thoracic CT scan and to reserve its use for specific indications.

Geotermometria das águas hipertermais do Sistema Aquífero Guarani no estado de São Paulo

Several geothermometers have been employed to determine the expected temperature in the groundwater reservoirs, most part of them based on the chemical equilibrium between thermal groundwaters and minerals which constitute the aquifer framework. Based on this principle, groundwater from Guarani Aquifer System, which presents temperatures upon to 38°C, classified as hyperthermal by the Brazilian Mineral Water Code, had their chemical composition evaluated with the main purpose to determine the expected temperatures in the reservoir based on the application of several geothermometers. These groundwaters can be classified as Na-HCO3 type evolving to Na-HCO3-Cl-SO4 type due the increase in sulphate and chloride concentrations. Measured groundwater temperatures show a good correlation with the depth of the aquifer, indicating an average geothermal gradient of 27.7°C/km. The lowest geothermal gradients, bellow 25°C/km, are observed in the central portion of the study area; meanwhile the highest gradients are observed in NE and W portions of the study area. Quartz equilibrium based geothermometers return temperature over the measured temperatures, meanwhile chalcedony geothermometer returns temperatures near the measured in the wells, except for the wells located in the area which presents the lowest geothermal gradients. The geothermometers based on the equilibrium between Na/K have returned temperatures diverse from the measured at the field, meanwhile the geothermometer based on the equilibrium between Na/K/Ca has presented good match with groundwater which present temperatures under 50°C, due the thermodynamic equilibrium between these waters and feldspars. Geothermometers show evidences about mixtures between groundwaters from GAS and underlying units, especially in wells located in the SW portion of the study area.

Chlorine disinfection of dye wastewater: Implications for a commercial azo dye mixture

Azo dyes, the most widely used family of synthetic dyes, are often employed as colorants in areas such as textiles, plastics, foods/drugs/cosmetics, and electronics. Following their use in industrial applications, azo dyes have been found in effluents and various receiving waters. Chemical treatment of effluents containing azo dyes includes disinfection using chlorine, which can generate compounds of varying eco/genotoxicity. Among the widely known commercial azo dyes for synthetic fibers is C.I. Disperse Red 1. While this dye is known to exist as a complex mixture, reports of eco/genotoxicity involve the purified form. Bearing in mind the potential for adverse synergistic effects arising from exposures to chemical mixtures, the aim of the present study was to characterize the components of commercial Disperse Red 1 and its chlorine-mediated decoloration products and to evaluate their ecotoxicity and mutagenicity. In conducting the present study, Disperse Red 1 was treated with chlorine gas, and the solution obtained was analyzed with the aid of LC-ESI-MS/MS to identify the components present, and then evaluated for ecotoxicity and mutagenicity, using Daphnia similis and Salmonella/microsome assays, respectively. The results of this study indicated that chlorination of Disperse Red 1 produced four chlorinated aromatic compounds as the main products and that the degradation products were more ecotoxic than the parent dye. These results suggest that a disinfection process using chlorine should be avoided for effluents containing hydrophobic azo dyes such commercial Disperse Red 1. © 2012 Elsevier B.V..

Avaliação da eficácia e dos efeitos respiratórios da anestesia peridural torácica em cães

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Avaliação de duas doses de lidocaína, administradas à altura da primeira vértebra lombar sobre a analgesia trans-cirúrgica e parâmetros cardiorrespiratórios em cadelas submetidas à ovariohisterectomia

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Indução experimental de polioencefalomalacia em ovinos confinados ingerindo dieta com alto teor de enxofre

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Mapeamento da fertilidade do solo utilizando sistema de informação geográfica

Pós-graduação em Agronomia (Energia na Agricultura) - FCA

Alternativas para a cogeração de energia em uma indústria de chapas de fibra de madeira

Pós-graduação em Agronomia (Energia na Agricultura) - FCA