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RESUMORecentemente, a escassez global dos combustíveis fosseis, além de questões políticas, econômicas e ambientais impulsionaram a busca por combustíveis oriundos de fontes renováveis. Neste contexto, o biodiesel surge como um promissor combustível sucedâneo ao diesel mineral, seja parcial ou totalmente. O Brasil é o segundo maior produtor e consumidor mundial de biodiesel, sendo que o sebo bovino é o segundo insumo mais utilizado para a produção deste biocombustível no país, atrás apenas da soja. Diante disso, este artigo de revisão bibliográfica aborda as principais vantagens e limitações relacionadas ao uso desta matéria--prima para obtenção de biodiesel no Brasil, destacando fatores econômicos e ambientais, suas características físico--químicas, além de aspetos relativos à sua cadeia produtiva. PALAVRAS--CHAVE:Vantagens, Limitações, Sebo bovino, Biodiesel. ADVANTAGES AND LIMITATIONS OF BEEF TALLOW AS FEEDSTOCK FOR BRAZILIAN BIODIESEL INDUSTRY ABSTRACTRecently, the global shortage of fossil fuels, as well as political, economic and environmental issues, have boosted the search for fuels obtained from renewable sources. In this context, biodiesel emerges as a promising substitute fuel for mineral diesel, either partially or totally. Brazil is the second largest biodiesel producer and consumer in the world and beef tallow is the second most used feedstock to produce this biofuel in the country, after soybean. Thus, this review deals with the main advantages and limitations related to beef tallow use as source for biodiesel production in Brazil. It is emphasized beef tallow economical and environmental factors, its physical and chemical properties, as well as aspects concerning its production chain.

Flaxseed gum (FG)-based films were developed with the addition of glycerol as a plasticizer and glutaraldehyde as a crosslinking agent. HCl was added to improve crosslinking and decrease the hydrophilicity of the matrix. Different cellulose nanocrystal (CN) amounts were used as reinforcements in the optimum FG formulation. The crosslinking process at pH 3.5 led to a lower solubility of FG in water (from 100% to 53%) and an increase in thermal stability (from 160 ºC to 209 ºC). FTIR analysis confirmed a reduction in the-OH band due to crosslinking between the hydroxyl groups of FG. A diffuse diffraction pattern was observed for all FG films. The addition of 4% w/w of CN contributed to reduction of water solubility (from 53% to 20.8%) and absorption (from 21.9% to 6.8%). Finally, an improvement was observed in the tensile mechanical properties in the nanocomposites, showing satisfactory results for the proposed formulations, mainly with 8% w/w of CN added to the matrix. Overall, this study demonstrated that FG/CN nanocomposites are promising materials to be use as a sustainable biopolymer for application as bioplastics.

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Engine performance behavior was investigated by adding some considerations in the usual cycle such as: influence of the temperature in the k coefficient, process gas behaving according to the virial equation and effect of initial temperature of the air. To determine the relationship among independent variables including temperature of the flame, temperature of the flue gas, thermal efficiency and effective average pressure analysis of the some methodologies was used. Comparison between different methodologies shows that the one regarding the virial equation model has not provided substantial variations in the studied variables. The results showed that adding and considering the non-idealities of the process became the findings closer to the reality due to thermal efficiency and air temperatures decreased when the real process has to be regarded.

Nowadays, due to the high level of competitiveness of the market some companies have sought to find a better administrative and operational efficiency. The technique of statistical process control (SPC) is one the statistical tools that allows a better view of abnormalities in the process and consequent improvement in the quality and productivity of the companies. Developed and widely applied in the production lines of manufactured goods, the SPC has shown a great potential for use in the optimization process of waste treatment. In this context, the present study aimed to characterize the physicochemical properties of the treated effluent from the oilseed agroindustry and analyze the variability of the wastewater treatment process using Shewhart control letters interpreted trough eight criteria of non-randomness proposed by the ISO 8258:1991. The samples collected and the analytical procedures were performed by reference methodologies for the analysis of water and waste water. The statistical analysis consisted in the codification of the variables, Dixon test application and preparation of control letters. The results showed that 10 parameters are out of statistical control of the process, which has shown a consistent variability with five of the eight criteria for detecting special causes, however 9 variables were under statistical process control. In this perspective we note the instability of the process in the effluent treatment of the oilseed agroindustry, which can be corrected with actions that minimize the occurrence of special causes and anticipates the decision to be made regarding the treatment of effluents.

Engine performance behavior was investigated by adding some considerations in the usual cycle such as: influence of the temperature in the k coefficient, process gas behaving according to the virial equation and effect of initial temperature of the air. To determine the relationship among independent variables including temperature of the flame, temperature of the flue gas, thermal efficiency and effective average pressure analysis of the some methodologies was used. Comparison between different methodologies shows that the one regarding the virial equation model with influence of temperature in the k coefficient could estimate better thermal efficiency. The results showed that adding and considering the non-idealities of the process became the findings closer to the reality due to thermal efficiency and air temperatures decreased when the real process has to be regarded.