Vicosa, Brazil
Vicosa, Brazil
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de Castro V.V.,Grande Rio University | Mazzini Fontoura L.A.,Cientec Inc. | Benfica J.D.,Grande Rio University | Seferin M.,Grande Rio University | And 2 more authors.
Wear | Year: 2016

The purpose of this work was to evaluate the sliding wear characteristics of SAE 1045 and SAE 52100 steels with different microstructures in the presence of pure biodiesel, a biodiesel-diesel blend (50% diesel+50% biodiesel) and commercial diesel fuel. Non-lubricated tests (dry) were also performed for comparison. For SAE 1045, samples were given a hardening heat treatment (austenitization at 830 °C and water quenching). For SAE 52100, the heat treatment was austenitization at 850 °C followed by oil quenching. Tempering at 100 °C and 300 °C was used for SAE 1045, and tempering at 100 °C and 200 °C was used for SAE 52100. As a result, the samples had four different hardness and microstructure combinations: tempered martensite in SAE 1045 and tempered martensite with chromium carbides in SAE 52100. Wear testing was performed using a pin-on-disk tribometer, 1.8 m/s sliding speed, 14.7 N load and 4400 m sliding distance following the ASTM G99-04 standard. Wear track surfaces were characterized using microindentation hardness and scanning electron microscopy. The results exhibited a tendency to decrease wear width, volume loss and wear coefficient when adding biodiesel to diesel for both SAE 1045 and SAE 52100 steels. Martensite produced by heat treatments increased the wear resistance. For both SAE 1045 and SAE 52100 steels, abrasive wear is dominant in both dry and lubricated conditions. © 2016 Elsevier B.V.


Fae Gomes G.M.,Federal University of Rio Grande do Sul | Fae Gomes G.M.,Cientec Inc. | Fae Gomes G.M.,University of the Rio dos Sinos Valley | Vilela A.C.F.,Federal University of Rio Grande do Sul | And 3 more authors.
Journal of Cleaner Production | Year: 2013

Biomass and coal are two vastly available energy sources that have been under-utilized for thermoelectric generation within the available energy matrix in Brazil, considering that the southern region has an excellent potential for the use of biomass as a decentralized energy source and the Brazilian coal reserves are totally distributed in this region. So, this paper makes an analysis concerning the use of the southern Brazilian coal together with the biomass available in the same region through a cleaner production approach in order to decrease the generation of solid wastes-ashes-and produce atmospheric emissions on a more environmental friendlyway through a decentralized energy generation system. A review on the possibility of using the coal ash - from its cofiring with wood wastes and the use of limestone for desulfurization - as a low-cost material for the production of sand lime bricks is evaluated. Then, results obtained from tests that technologically evaluated the use of those fuels on a bubbling fluidized bed are presented. Finally, the economical possibility of developing an integrated system for energy production, carbon crediting and production of building materials using the cofiring of biomass and coal with limestone addition in Small Thermal Power Plants is assessed. The results showed a good possibility for the increment of biomass use in the southern Brazilian region and the data obtained from combustion tests are already sufficient to support the launch of definitive projects to provide steam generation from renewable sources on a decentralized way. The revision reveals that the Brazilian ash composition is prone to react with the high CaO content in wood ashes and the limestone addition can be adjusted for the production of a suitable composition for the direct use on sand lime brick production. This integrated system proposed has the possibility of having annual revenue about US$ 1,105,000.00. © 2012 Elsevier Ltd. All rights reserved.


Gomes G.M.F.,Cientec Inc. | Gomes G.M.F.,University of the Rio dos Sinos Valley | Philipssen C.,Federal University of Rio Grande do Sul | Bard E.K.,Cientec Inc. | Souza G.,Cientec Inc.
Brazilian Journal of Chemical Engineering | Year: 2016

Although fluidized bed in situ desulphurization from coal combustion has been widely studied, there are aspects that remain under investigation. Additionally, few publications address Brazilian coal desulphurization via fluidized beds. This study used a 250 kWth bubbling fluidized bed pilot plant to analyze different aspects of the dolomite desulphurization of two Brazilian coals. Superficial velocities of 0.38 and 0.46 m/s, flue gas recycling, Ca/S molar ratios and elutriation were assessed. Results confirmed the influence of the Ca/S molar ratio and superficial velocity - SO2 conversion up to 60.5% was achieved for one coal type, and 70.9% was achieved for the other type. A recycling ratio of 54.6% could increase SO2 conversion up to 86.1%. Elutriation and collection of ashes and Ca-containing products did not present the same behavior because a lower wt. % of CaO was collected by the gas controlled mechanism compared to the ash.


Fae Gomes G.M.,Cientec Inc. | Fae Gomes G.M.,Federal University of Rio Grande do Sul | Encarnacao F.,Associacao Riograndense de Empreendimentos de Assistcncia Tecnica e Extensao Rural EMATER RS
Environmental Research | Year: 2012

Black wattle silviculture is an important activity in southern Brazil. Much of the wood is used in the production of charcoal and the pyrolysis products impacts on air quality. This paper estimates the level of atmospheric contamination from the production of charcoal in one region of Brazil. We describe a low-cost charcoal kiln that can capture condensable gases and we estimate the levels of exposure of kiln workers to carbon monoxide. The latter results indicated that exposure to carbon monoxide can be reduced from an average of 950. ppm to 907. ppm and the mass of gases reduced by 16.8%. © 2012 Elsevier Inc.


Lorscheitter M.L.,Federal University of Rio Grande do Sul | Roth L.,Cientec Inc.
Anuario do Instituto de Geociencias | Year: 2013

The palynology of sedimentary profiles aiming palaeoenvironmental reconstructions require quantitative analysis, so that the environment can be inferred from the palynomorphs. The percentage of pollen grains in each taxon, in relation to the total counted in the sample is largely used in this study, but often can significantly distort the results because it is a relative analysis. The absolute analysis of pollen concentration can correct these distortions, and should also be included in the methodology to ensure more reliable results.


de Souza G.,Federal University of Rio Grande do Sul | de Souza G.,Cientec Inc. | Ruoso C.,Federal University of Rio Grande do Sul | Marcilio N.R.,Federal University of Rio Grande do Sul | Perez-Lopez O.W.,Federal University of Rio Grande do Sul
Chemical Engineering Communications | Year: 2016

Mg-Co-Al mixed oxides were synthesized by the precipitation method and evaluated for dry reforming of methane. The samples were characterized by thermal techniques (TGA/DTA, NH3-TPD, H2-TPR, and TPO), specific surface area, and X-ray diffraction (XRD). Activity runs were conducted at atmospheric pressure, temperatures between 400 and 550°C, a CH4/CO2 molar ratio of 1, and a space velocity of 6000 NmL CH4/g/h. The partial substitution of Co with Mg increased the surface area and thermal stability and changed the reducibility and acid-base properties of the samples. These modifications led to a higher activity for dry reforming of methane for the catalyst with Mg/Co = 0.5, primarily due to its enhanced thermal stability. However, its higher activity was followed by higher amounts of coke. The different activation procedures highlighted Co3O4 as the main active phase rather than the Co-mixed oxides. Therefore, milder activation temperatures are required to properly reduce the Co3O4 phase and avoid sintering. © 2016, Copyright © Taylor & Francis Group, LLC.


Cardoso A.M.,Pontifical Catholic University of Rio Grande do Sul | Horn M.B.,Pontifical Catholic University of Rio Grande do Sul | Ferret L.S.,Cientec Inc. | Azevedo C.M.N.,Pontifical Catholic University of Rio Grande do Sul | Pires M.,Pontifical Catholic University of Rio Grande do Sul
Journal of Hazardous Materials | Year: 2015

Several researchers have reported zeolite synthesis using coal ash for a wide range of applications. However, little attention has been given to green processes, including moderate synthesis conditions, using waste as raw material and effluent reuse or reduction. In this study, Brazilian coal fly ashes were used for integrated synthesis of zeolites 4A and Na-P1 by two different routes and under moderate operating conditions (temperature and pressure). Both procedures produced zeolites with similar conversions (zeolite 4A at 82% purity and zeolite Na-P1 at 57-61%) and high CEC values (zeolites 4A: 4.5meqCa2+g-1 and zeolites Na-P1: 2.6-2.8meqNH4 +g-1). However, process 1 generated less effluent for the zeolite mass produced (7mLg-1), with low residual Si and Al levels and 74% of the Si available in the coal fly ash incorporated into the zeolite, while only 55% is used in process 2. For use as a builder in detergents, synthetic zeolite 4A exhibited conformity parameters equal to or greater than those of the commercial zeolite adopted as reference. Treatment of swine wastewater with zeolite Na-P1 resulted in a high removal capacity for total ammoniacal nitrogen (31mgg-1). © 2015 Elsevier B.V.


Susin R.C.,Fundacao de Ciencia E Tecnologia CIEN TEC | Mior R.,Fundacao de Ciencia E Tecnologia CIEN TEC | Da Costa Dias V.M.,Cientec Inc.
Brazilian Journal of Food Technology | Year: 2015

Chocolate consumption is usually associated with enjoyment, milk chocolate desserts being a very popular choice. Besides, the literature provides data suggesting health benefits for chocolate products as compared to non-chocolate candies. However, the lipid composition of cocoa and its commercial products has yet to be completely elucidated and understood, although much research has been carried out with this objective. Contributions to this objective frequently face difficulties in the field of Analytical Chemistry due to the complexity of the composition of such a food. On the other hand, the sodium content of foods is currently a major concern. Thus, this work aims to provide information concerning the composition of commercial milk chocolate in terms of its fatty acid profile and sodium content. To achieve this purpose, analytical adjustments and improvements to the methodology were made and described in this paper. Sodium (FAAS) and a total of 50 fatty acids (GC-FID) were determined in eight samples of milk chocolate bars from different manufacturers. The samples were purchased from retailers in Porto Alegre - Brazil. In the determination of the fatty acids, possible losses during methylation deserved special attention and were studied. Nevertheless, large differences were not found in comparison with the nutritional facts declared on the label. However, the results obtained for sodium demonstrated the importance of food inspection, considering the discrepancies found.


PubMed | Cientec Inc.
Type: | Journal: Environmental research | Year: 2012

Black wattle silviculture is an important activity in southern Brazil. Much of the wood is used in the production of charcoal and the pyrolysis products impacts on air quality. This paper estimates the level of atmospheric contamination from the production of charcoal in one region of Brazil. We describe a low-cost charcoal kiln that can capture condensable gases and we estimate the levels of exposure of kiln workers to carbon monoxide. The latter results indicated that exposure to carbon monoxide can be reduced from an average of 950 ppm to 907 ppm and the mass of gases reduced by 16.8%.

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