Recycling of silicon carbide and corn starch as binder originating from commercial starch consolidation

The main goal of this work is to demonstrate that the use of recycled material originated from SiC ceramics is viable. These ceramics were produced by commercial starch consolidation process. Before calcination stage, surplus of these materials always appears. This surplus is rich in SiC and starch. Samples were made by material previously milled in automatic mortar and sieved (100 Tyler). Later, 10% of distilled water was added to the material and the mixture was pressed at 40 MPa. In order to characterize the ceramic, three point flexural test were made, according to the ASTM C1161/94 norm. The results were analyzed by Weibull statistical method. Apparent density and porosity measures also were made, according to ASTM C20/87 norm. A verification of the surface was made in the fracture area by the depth from focus method and SEM image analysis. The results showed that the recycling process is fully viable, being a good economic option and reduce possible pollutant effect to the environment.

Brazilian results on structural masonry concrete blocks

The purpose of this paper is to study the mechanical behavior of concrete blocks and prisms when performing axial compression tests within the Brazilian base of knowledge, intending to foment data of this kind for a world-based network. The blocks were built using five different mixtures in which the quantity of cement and the compacting ratio (density) were varied (during the fabrication process). The three-course-high prisms were assembled using 1 cm (0.39 in.) thick full-bedded joints, always trying to leave the mortar's characteristics constant. The axial compression tests were conducted according to Brazilian practice code recommendations, because most of these standards are very similar to international practice codes. The compressive strength, strains, and rupture form of each mixture studied were recorded. Attempts were made to correlate the strength, efficiency ratio (block strength/prism strength) of the prisms, strains, and rupture form; with the quantity of cement and compacting ratio. The data are presented in tables and figures, and the obtained results are discussed throughout the text. Copyright © 2007, American Concrete Institute. All rights reserved.

From industrial economics to digital economics: an introduction to the transition

Includes bibliography

Determinação do teor de extrato etéreo de grãos de oleaginosas através de diferentes processamentos

The objective of this work was to determine the ether extract content of peanut and canola seeds, with extraction in Soxhlet apparatus and with three types of processing: grinding in ball mill type; maceration in mortar and grind into micro mill after maceration in mortar. Data were analyzed in an entirely randomized design with 3 treatments and 12 replicates, submitted to variance analysis and the means were compared using Tukey test (P<0.05) with routines of the SAS statistical package. The largest percentage of ether extract was obtained in the treatment which the peanuts were subjected to a greater number of extractions (56.43%), and all treatments presented different results(P <0.05). In canola grains, it was observed that the extraction with the method of grinding in ball mill and the method of sequential extraction (macerate + ground in micro mill) were statistically similar (43.52 and 42.35% respectively), and these methods were more efficient (P <0.05) to extract the ether extract than the treatment in which the grains were only macerated. For peanut grains it was concluded that the most efficient method was the sequential one and to the canola grain, it can be used only a grinding mill as samples processing witch will be submitted to ether extract extraction.

An anisotropic linear elastic boundary element formulation for masonry wall analysis

This work presents an application of a Boundary Element Method (BEM) formulation for anisotropic body analysis using isotropic fundamental solution. The anisotropy is considered by expressing a residual elastic tensor as the difference of the anisotropic and isotropic elastic tensors. Internal variables and cell discretization of the domain are considered. Masonry is a composite material consisting of bricks (masonry units), mortar and the bond between them and it is necessary to take account of anisotropy in this type of structure. The paper presents the formulation, the elastic tensor of the anisotropic medium properties and the algebraic procedure. Two examples are shown to validate the formulation and good agreement was obtained when comparing analytical and numerical results. Two further examples in which masonry walls were simulated, are used to demonstrate that the presented formulation shows close agreement between BE numerical results and different Finite Element (FE) models. © 2012 Elsevier Ltd.

Alkali activated materials based on fluid catalytic cracking catalyst residue (FCC): Influence of SiO2/Na2O and H 2O/FCC ratio on mechanical strength and microstructure

Reuse of industrial and agricultural wastes as supplementary cementitious materials (SCMs) in concrete and mortar productions contribute to sustainable development. In this context, fluid catalytic cracking catalyst residue (spent FCC), a byproduct from the petroleum industry and petrol refineries, have been studied as SCM in blended Portland cement in the last years. Nevertheless, another environmental friendly alternative has been conducted in order to produce alternative binders with low CO2 emissions. The use of aluminosilicate materials in the production of alkali-activated materials (AAMs) is an ongoing research topic which can present low CO2 emissions associated. Hence, this paper studies some variables that can influence the production of AAM based on spent FCC. Specifically, the influence of SiO 2/Na2O molar ratio and the H2O/spent FCC mass ratio on the mechanical strength and microstructure are assessed. Some instrumental techniques, such as SEM, XRD, pH and electrical conductivity measurements, and MIP are performed in order to assess the microstructure of formed alkali-activated binder. Alkali activated mortars with compressive strength up to 80 MPa can be formed after curing for 3 days at 65°C. The research demonstrates the potential of spent FCC to produce alkali-activated cements and the importance of SiO2/Na2O molar ratio and the H2O/spent FCC mass ratio in optimising properties and microstructure. © 2013 Elsevier Ltd. All rights reserved.

Use of slag/sugar cane bagasse ash (SCBA) blends in the production of alkali-activated materials

Blast furnace slag (BFS)/sugar cane bagasse ash (SCBA) blends were assessed for the production of alkali-activated pastes and mortars. SCBA was collected from a lagoon in which wastes from a sugar cane industry were poured. After previous dry and grinding processes, SCBA was chemically characterized: it had a large percentage of organic matter (ca. 25%). Solutions of sodium hydroxide and sodium silicate were used as activating reagents. Different BFS/SCBA mixtures were studied, replacing part of the BFS by SCBA from 0 to 40% by weight. The mechanical strength of mortar was measured, obtaining values about 60 MPa of compressive strength for BFS/SCBA systems after 270 days of curing at 20 °C. Also, microstructural properties were assessed by means of SEM, TGA, XRD, pH, electrical conductivity, FTIR spectroscopy and MIP. Results showed a good stability of matrices developed by means of alkali-activation. It was demonstrated that sugar cane bagasse ash is an interesting source for preparing alkali-activated binders. © 2013 by the authors; licensee MDPI, Basel, Switzerland.

Avaliação da conversão da resina composta polimerizada com luz halógena e LED com espectometria do infravermelho

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estudo teórico e experimental das ligações diretas contra-fiadas entre paredes de blocos de concreto em escala real e reduzida 1:4

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Utilização do pó de pedra basáltica em substituição à areia natural do concreto

Pós-graduação em Engenharia Civil - FEIS

Estudo experimental de ligações entre paredes de alvenaria estrutural de blocos cerâmicos sujeitas a ações verticais

Pós-graduação em Engenharia Civil - FEIS

Avaliação do desempenho de argamassas com adição de cinza do bagaço de cana-de-açúcar

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Análise do comportamento experimental e numérico de prismas de alvenaria estrutural utilizando o elemento finito prismático regular parabólico

Pós-graduação em Engenharia Civil - FEIS

Procedimento numérico para análise de vigas de alvenaria estrutural submetidas à flexão simples

Pós-graduação em Engenharia Civil - FEIS

Diagnósticos dos procedimentos executivos nos canteiros de obras de alvenaria estrutural

Pós-graduação em Engenharia Civil - FEIS