Materials Science Forum Vols. 727-728

Abstract: The steady rise in emissions from burning fossil fuels has caused increasing concern about their environmental impact. Lignocellulosic biomass can produce alternatives for gasoline and diesel by thermal conversion. Sorghum is used for animal feed since the feed value of its grain is similar to corn. The grain has more protein and fat than corn, but is lower in vitamin A. When compared with corn on a per pound basis grain sorghum feeding value ranges from 90% to nearly equal to corn. The grain is highly palatable to livestock, and intake seldom limits livestock productivity. Sorghum bagasse is the residue of sorghum after milling. The present work had the objective of characterizing sorghum bagasse for energetic use, especially to produce bio-oil by fast pyrolysis. The first step in pyrolysis process is the biomass characterization, since some kinds of particles are not suitable to be processed and need a previous preparation. For sorghum bagasse the performed physical analyses were: size distribution and medium diameter, and solids true density; the main chemical analyses were: ultimate analysis, proximate analysis, chemical composition and gross calorific value.

Abstract: There is an increasing concern about environmental problems associated with the rising emissions of CO₂, NO_x and SO_x due to the use of fossil fuels. Thus, renewable energy based on biomass could contribute to relieve the environmental and energy problems. Biomass energy conversion covers the processing of industrial and agricultural wastes, taking advantage of materials that would be discarded. In this work, tobacco residue characterization is studied; the material is a waste of tobacco industry. Values of true density were inferred for three different ranges of particle sizes and particles size and shape were studied for the three set of particles using dynamic digital image processing. The results show differences in physical characteristics of the biomass, varying the particle size.

Abstract: Several nanomaterials have been currently developed and new applications has became possible due to the special materials performance requirements. The TiO₂ nanoparticles are of special interest due to the wide range of applications from cosmetics to paint and new applications have continuously been searched. However, the effect of these particles into the environment need detailed investigation since some deleterious effects on the ecosystems have been observed. This paper deals with the mechanism of nanoparticles absorption/desorption by soil landfills. A long term simulation of the nanoparticles motion and contamination plume is carried out in the Volta Redonda Municipal Waste landfill and main transport parameters are determined. The model is used to predict the concentration of TiO₂ nanoparticles in suspension on the leachate of Municipal Waste landfills and the rate of particles dynamically attached into the soil particles

Abstract: In the latest years, several studies were realized concerning about the application of biocidal compound in polymers or ceramics, due to the risk offered to human life by the action of pathogenic microorganisms. Many of these materials, considered special, are directed to medical area and to the food industry, for the production of food packaging. Essential oils (EOs) are aromatic liquids obtained from plant material that have bactericidal activities. One example of essential oil is Eugenol, major component of clove oil. Eugenol is the essential oil compound that better reduce the bacterial activities. This work aimed to study the processing conditions used to incorporate an antimicrobial additive in polypropylene in order to find the processing conditions in which the sample obtained have the best bactericidal properties. To evaluate the effect of the processing conditions in the bactericidal action of the compound it was used an statistical experimental factorial planning. The samples obtained underwent microbiological and physical tests to prove its antibactericidal efficiency. The preview results obtained showed significance to some of the studied variables.

Abstract: This work aims to evaluate the effect of polymer content in the preparation of membranes obtained from polyamide 6/national clay nanocomposites. The polymeric membranes were produced varying the polymer content at 20 and 22% and using the technique of precipitation by immersion, which consists of three main steps: preparation a homogeneous polymer solution, scattering the solution on a surface forming a film of determined thickness and finally formation of polymeric structure of membrane by separation phases the system. The obtained results by scanning electron microscopy (SEM) indicated that the content of polymer changes the pore formation, the distribution and density, thereby obtaining membranes with different pore sizes, and it was possible to observe that the higher the polymer content, the lower will the pore diameter and more thicker will be the selective membrane layer.

Abstract: Much attention is being given to developing nanocomposites with layered silicates, owing to the great need for advanced materials engineering and the fact that the pure polymers do not present the behavior or properties needed for certain applications within that context, the objective of this study was to influence of the molecular weight of polyamide 6 in obtaining nanocomposites with national organoclay. For this, the mixture of polyamide 6/ organoclay was processed in a twin screw extruder, and then was characterized by thermogravimetry (TG), X-ray diffraction (XRD) and heat deflection temperature (HDT). It was then possible to observe by XRD to obtain a structure exfoliated or partially exfoliated in the studied systems. For TG, it was found that the nanocomposites were stabilities higher than the pure polymer. And the values of HDT of systems were significantly higher than those of pure polyamide 6.

Abstract: Cement pavement block are worldwide used to cover streets as an alternative to petroleum-base asphalt. These blocks are required to be not only strong but also dense and impact resistant. Packing of the precursor materials is an important factor in the final properties. In principal, this could be improved by the incorporation of another stable powder material like a local cost mineral residue or waste. The objective of this work is to investigate the effect of addition of a powder waste on the composition of a cement pavement block by means of an experimental planning. This planning was associated with a factorial design modeling based on composition variables including sand, gravel and the waste as well as the water/cement ratio. The response surfaces were evaluated and optimum proportion variables defined for best combination of properties.

Abstract: The city of Cachoeiro de Itapemirim, in the southwest of Brazil, has a large industrial activity related to the extraction of ornamental stones. This brings jobs and income to the state of Espirito Santo but also cause problems due to the discard of the sludge resulting from the stone processing operations (SPO). The reuse of this SPO in construction materials such as plaster and bricks has been proposed as an alternative to reduce its environmental impact. This work evaluates another low cost alternative based on the incorporation of the SPO in the fabrication of cement pavement blocks. Using an experimental planning method, the mixture of sand, gravel and SPO, jointly with a water/cement proportion, was investigated for the method surface response. Based on this statistical method, pavement blocks with an apparent density of 1.96 g/cm³ were found for incorporation in the range of 10 to 34%.

Abstract: The objectives of this paper are study effect of dispersion of hard alumina (Al₂O₃) microparticles-filled polypropylene (PP) composites. Al₂O₃/PP composites containing 1.0 – 5.0 wt% of the Al₂O₃ were prepared through melt blending and specimens were produced through injection moulding technique. This study sets out to evaluate the influence of adding hard particles to the mechanical properties of the composite obtained while keeping the processing characteristics of the material. The material was characterized as thermo gravimetric analysis (TGA) and scanning electron microscopy (SEM). The tensile tests performed showed an increase in the mechanical properties of the composite (modulus and elongation (%)) by increasing the Al₂O₃ content. The SEM images show a change in the fracture behavior between pure PP (brittle fracture) and Al₂O₃/PP composites containing 3.0 and 5.0 wt % (ductile fracture). The research aims to establish a new parameter for the development of products and advances in the application of this material.

Abstract: The main purpose of this study was to determine the influence of process variables on granulation of ordinary super phosphate. The experiments were performed in a drum with an internal volume of 25 l and the evaluated variables were rotation speed, liquid phase, granulation time and fill level of the drum granulator. Central Composite Design (CCD) was used to choose the experimental conditions. The correlation between data and process variables was established using Multiple Regression. The granulation products were analyzed using standard separators and the Haver CPA photo-optical particle size measurement system. The tendency toward granulation and formation of coarse or fines could be predicted according to the specific surface of the granulation product and the granulation size distribution was found to be greatly dependent on the variable studies.