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Sandwich panels made with a bamboo core of different dimensions, packing geometries and facing materials are subjected to three-point bending tests and assessed through statistical and failure analysis. In addition to promoting a circular economy, this architecture holds great promise for replacing secondary structural components in sustainable construction and transportation facilities. The statistical analysis responses are associated with the equivalent density of the panels, flexural strength and modulus of the panels, skin stress and core shear strength and modulus. Individual bamboo rings are also characterised using physic mechanical and interfacial bonding tests. Treated aluminium face sheets provide the best mechanical performance compared to glass fibre-reinforced composite (GFRP) ones by increasing the overall properties of the sandwich panels. The specific face sheet material and void percentage affect the equivalent density, with lower values (~ 0.48 g/cm3) when using GFRP skins, larger bamboo rings and cubic packing. Sandwich panels with 30 mm bamboo rings and hexagonal packing provide higher flexural properties, i.e. ~ 43 MPa strength and ~ 7.6 GPa modulus, and skin stress (~ 288 MPa), while those with 20 mm bamboo rings have higher shear stiffness (~ 132 MPa) and resistance (~ 3.33 MPa). Sandwich panels made with aluminium skins show evident skin-polymer debonding, while those with GFRP have premature skin failure and lower structural performance. The proposed sandwich panels present remarkable and competitive mechanical performance concerning commercial analogous structures, generally used in the aeronautical and automotive industries.

O presente estudo tem como problemática se o fornecedor tem reponsabilidade objetiva por vício do produto? Diante disso, o art.18 do CDC prevê que os fornecedores de produtos de consumo duráveis ou não duráveis respondem de forma solidariamente pelos vícios de qualidade ou de quantidade que os tornem impróprios ou inadequados ao consumo para que se o destinam. Ademais, para melhor compreensão acerca do tema, será abordado os tipos de vícios trazidos pelo código de defesa do consumidor, as formas de responsabilização impostas aos fornecedores quando seus produtos apresentam alguma falha, quais seus prazos e ainda qual tipo de penalidade a eles aplicadas para analisar de forma mais aprofundada o assunto principal sobre a reponsabilidade por vicio de produtos e distingui-los dos demais tipos. E quanto a metodologia aplicada, será por meio de pesquisa exploratória, de abordagem qualitativa, com intuito de gerar conhecimento para elaboração do texto cientifico, como o trabalho de conclusão de curso, se faz necessário um estudo pelo método dedutivo, utilizando-se da e de estudos dos principais doutrinadores sobre os assuntos estudados.

This is the first attempt to combine disposed bottle caps and natural fibres into sandwich panels. A full factorial design is performed to identify the effects of the skin type (aluminium or coir fibre reinforced laminates) and bottle cap core packing (cubic and orthotropic) on the mechanical properties of the proposed panels. The coir fibre composite skin provides maximum core shear strength, 29 % higher than the aluminium-based panels, in cubic packing, while the flexural modulus is reduced by 45 %. An interlocking effect between the skin and the core is evidenced when coir fibre composites are used. In addition, the cubic cell packing increases the specific mechanical properties, even though with a higher density. The results highlight a promising association of green components and plastic bottle caps for secondary structural applications.

As Tecnologias da Informação e Comunicação vem se tornando um meio de auxiliar na promoção de um planejamento urbano mais efetivo. Nesse contexto, a modelagem da informações da cidade emerge como uma forma eficiente de planejamento urbano. Este trabalho explora o conceito de City Information Modeling – Data Layer (CIM-DL) como proposta para o delineamento de um sistema de auxílio ao processo decisório de planejamento urbano. Esse trabalho apresenta os resultados preliminares de uma pesquisa de mestrado que faz uso do Design Science Research para propor um modelo de CIM-DL. Os resultados parciais apontam para a necessidade da concepção de um protocolo estruturado para gestão da informação das cidades, que sirva como guia para a criação de um sistema integrador de dados a ser usado para auxiliar o processo decisório do planejamento e gestão dos municípios brasileiros.

A metodologia lean tem sido implementada nas organizações para otimizar processos e diminuir os desperdícios, assim eleva a competitividade perante a concorrência e a performance da mesma. Para manter a fabricação enxuta, diversas ferramentas podem ser implementadas na organização, sendo uma delas o mapeamento do fluxo de valor (MFV). Desta forma, o presente estudo tem como propósito mapear o fluxo de valor da fabricação de produtos extrusados pet food e identificar os desperdícios para propor melhorias. O método de pesquisa utilizado foi o estudo de caso, que permitiu a análise aprofundada do processo produtivo em uma organização de grande porte. Com a aplicação do MFV obteve-se como resultado o mapa do estado atual e após a análise o mapa do estado futuro. As sugestões de melhoria incluíram sincronizar a produção ao adotar o Kanban e supermercados para introduzir o fluxo puxado de produção. Por fim, houve a redução do lead time de 13,8 dias para 6,13 dias e a quantidade de operadores de 17 para 12. A partir do estudo realizado, pode-se identificar lacunas para pesquisas futuras.

Cementitious composites reinforced with silica, silicon carbide or carbon microfibres are designed, manufactured, characterised and tested as porous restrictor for aerostatic bearings. Carbon microfibres are residues obtained from the cutting process of carbon fibre-reinforced polymers. Porosity, permeability, flexural strength and stiffness are quite relevant in the design of aerostatic porous bearings. A 3141 full factorial design is carried out to identify the effects of particle inclusion and water-to-cement ratio(w/c) factors on the physical and mechanical properties of cementitious composites. Higher density material is achieved by adding silicon carbide. Higher porosity is obtained at 0.28 w/c level when silica and silicon carbide are used. Carbon microfibres are not effective under bending loads. Higher compressive strength is reached especially when silica particles are combined with 0.33 or 0.35 w/c. According to the permeability coefficient values the cementitious composites consisted of CMF (0.28 w/c), silica (0.30 w/c) or silicon carbide (0.30 w/c) inclusions are promising as porous restrictor; however, carbon microfibre porous bearings achieved the lowest air gap variation under the tested working conditions.

This work evaluates a new eco-friendly surface treatment method for coir fibres based on sodium bicarbonate (NaHCO3). The fibres are treated with 10 wt% NaHCO3 solution for different periods of time (24, 96 and 168 h). A 2141 Full Factorial Design is established to investigate the effect of the type of matrix (epoxy and polyester) and treatment time (24, 96 and 168 h) on the mechanical properties of coir fibre composites. X-Ray diffraction (XRD) analysis reveals that the treatment does not promote a complete change of cellulose-I into cellulose-II. However, the degradation of hemicellulose and pectin of the fibre surface is evidenced by the thermogravimetric (TGA) curves. The chemical treatment contributes to increase the fibre density and to reduce its thermal stability. Single fibre tensile tests reveal a gradual increase in the elastic modulus attributed to the treatment time factor. Epoxy composites presented higher tensile and flexural strength in comparison to polyester composites, which exhibit higher tensile and flexural modulus. The alkaline treatment does not affect the mechanical strength of the composites. However, higher tensile and flexural moduli are obtained when the treatment time increases to 96 or 168 h. The proposed treatment proves to be feasible and efficient to increase the stiffness of coir fibre composites, besides being less damaging to the environment after disposal when compared to strongly alkaline solutions such as NaOH.

This work focuses on the fabrication and characterisation of epoxy composites reinforced with natural fibre layers extracted from the inner bast (phloem) of the papaya plant (Carica papaya) under tensile and three-point bending loading. The papaya phloem is composed of fibrous laminas that wrap and reinforce the stem of the plant. A set of quasi-periodically arranged holes disrupt the continuity of these layers, through which the branches emerge. The fibres in each layer constitute an anisotropic honeycomb-like structure, whose elongated cells align along a single preferential direction. Papaya-reinforced epoxy composites are fabricated by hand lay-up and evaluated using two full-factorial designs based on the fibre-to-load direction in longitudinal (0°) and transverse (90°) conditions, for configurations without holes and alternating holes. Composites made with randomly-oriented short fibres are also evaluated along with the first experiment. The tensile and flexural properties obtained are compared to other materials in the literature to assess its potential as a structural material. The results show that the papaya bast fibre layers can be a promising reinforcement for polymeric composites.

A full factorial design (2 231 ) has been used to investigate the effect of the use of sodium hydroxide fibre treatment, Portland cement and uniaxial pressure on the physical and mechanical properties of hybrid short coir fibre reinforced composites (HSCoirFRCs). The response variables considered in this work were the apparent density, porosity, tensile and flexural strength , the modulus of elasticity and the Charpy impact resistance. The alkali treatment contributed not only to reduce the apparent porosity , but also to increase the mechanical properties of the HSCoirFRCs. A reduction of the impact resistance and an increase of the apparent density was also identified after treatment. Cold pressing significantly affected the physical and mechanical properties of the HSCoirFRCs. Higher pressure levels enhanced the wettability of the fibres and, consequently, the mechanical performance of the composites. The incorporation of cement microparticles as a second reinforcement phase was however not effective, leading to decreased strength and an increased apparent density of the materials. The HSCoirFRC structure can be considered an economical and sustainable alternative for future secondary structural parts in lightweight transport applications.

Over the last few decades, a significant amount of research has been focused on the use of natural fibres as reinforcement in polymers, due to their intrinsic properties such as sustainability, easy availability and processing, biodegradability and moderate mechanical strength. Among natural fibres, coir is a low-cost fibre extracted from coconut palm which is extensively produced in Brazil. A full factorial design was carried out to investigate the effects of the manufacturing and composition parameters on the mechanical and physical properties of short coir fibre–reinforced composites (SCoirFRCs). The random short fibres were mixed with epoxy polymer and compacted by uniaxial pressure. The physical and mechanical responses, namely, apparent density, impact resistance, flexural strength and modulus, were investigated under a design of experiment approach. SCoirFRCs fabricated with 35% of fibre volume fraction, 375 g/m2 of fibre grammage and HY956 epoxy hardener type achieved higher flexural modulus and impact resistance, while those consisting of 30 vol% of coir fibres, HY956 type and 300 g/m2 of grammage revealed higher flexural strength. The findings revealed that the mechanical properties of SCoirFRCs are substantially dominated by the properties of the matrix phase and fibre wettability.

This work investigates the effect of silica nanoparticles functionalized with poly-diallyldimethylammonium chloride (PDDA) and silica microparticle inclusions (1.0 wt% and 3.5 wt%) on the impact resistance of hybrid carbon fibre reinforced composite laminates (HCFRCs) and tensile modulus of particle reinforced polymers (PRPs) via Full-Factorial Design of Experiments. The data were analysed with Analysis of Variance (ANOVA). The inclusion of particles led to reduced impact absorption of HCFRCs, except for composites with 1.0 wt% of silica in microscale, which provides an increase of 11.75% in the impact resistance. Microstructural analysis of fractured impact samples revealed pull-out as the predominant fracture mode in 1.0 wt% silica microparticle composites. Such mechanism leads to impact energy dissipation which may explain the increased impact resistance of these samples.

Este artigo realiza uma discussão inicial acerca das relações de poder e da violência nas áreas de fronteira reocupadas por diferentes grupos sociais, tais como mineradores tradicionais, prostitutas, peões e comerciantes, nos espaços dos garimpos, constituídos a partir das descobertas de jazidas diamantíferas no município de Juína, Noroeste de Mato Grosso, Brasil, entre os anos de 1987 e 1994. O poder é compreendido como relação legítima de comando e obediência, ao passo que violência é pensada como instrumento de dominação e imposição sobre o outro em locais cuja presença do Estado é incipiente. Weber e Arendt são importantes referências para o diálogo da relação entre poder e violência. A fronteira é pensada na lógica das frentes de expansão e pioneirismo de José de Souza Martins. O recurso da história oral foi utilizado para recuperar relatos de violência nesses espaços, em especial no Garimpo do Arroz.

Surface modification induced by sodium carbonate on coir fibres was studied in view of its application as a reinforcing agent in polyester and epoxy polymer fibre-reinforced composites. Coir fibres were treated with a 10 wt% sodium carbonate solution for different periods of time (24, 96 and 168 h) at room temperature. The surface treatment was evaluated by scanning electron microscopy, X-ray diffraction and thermogravimetric analysis. Tensile, flexural and impact properties of treated and untreated coir fibre-reinforced composites were compared. Coir-reinforced epoxy and polyester composites were manufactured by the uniform dispersion of randomly oriented coir fibres within the polymeric matrix. Tensile and flexural modulus of coir-reinforced polyester composites increased nearly 28% and 25%, respectively after 96 h of coir treatment. An analogous increase of 31% and 17% was obtained for coir-reinforced epoxy composites. In addition, coir-polyester composites achieved superior tensile (∼17%) and flexural (∼5%) modulus and impact strength (∼193%) compared with coir-epoxy-derived composites. In contrast, coir-epoxy composites led to superior tensile and flexural strength. The experimental results revealed that sodium carbonate solution effectively removes hemicellulosic compounds, promotes swelling and increases superficial roughness of the fibres, improving the mechanical properties (modulus and strength) of the coir-reinforced composites studied.

Lean methodology has been implemented in organizations to improve processes and reduce waste, thus improving competitiveness and performance. In order to maintain lean manufacturing, several tools can be implemented in the organization, one of them being Value Stream Mapping (VSM). Thus, the present study aims to map the flow of value of the manufacture of extruded pet food products, thus identifying the wastes inherent to the same and proposing improvements. The research method used was the case study, which allowed the in-depth analysis of the productive process in a large organization. With the application of the VSM we obtained as a result the map of the current state and after the analysis the map of the future state. Suggestions for improvement included synchronizing production while adopting Kanban and supermarkets to introduce the pulled production flow. Finally, there was a reduction of lead time to 13,8 days for 6.13 days and the number of operators to 17 for 12. From the study, one can identify gaps for future research. A metodologia lean tem sido implementada nas organizações para otimizar processos e diminuir os desperdícios, assim eleva a competitividade perante a concorrência e a performance da mesma. Para manter a fabricação enxuta, diversas ferramentas podem ser implementadas na organização, sendo uma delas o mapeamento do fluxo de valor (MFV). Desta forma, o presente estudo tem como propósito mapear o fluxo de valor da fabricação de produtos extrusados pet food e identificar os desperdícios para propor melhorias. O método de pesquisa utilizado foi o estudo de caso, que permitiu a análise aprofundada do processo produtivo em uma organização de grande porte. Com a aplicação do MFV obteve-se como resultado o mapa do estado atual e após a análise o mapa do estado futuro. As sugestões de melhoria incluíram sincronizar a produção ao adotar o Kanban e supermercados para introduzir o fluxo puxado de produção. Por fim, houve a redução do lead time de 13,8 dias para 6,13 dias e a quantidade de operadores de 17 para 12. A partir do estudo realizado, pode-se identificar lacunas para pesquisas futuras.

The work describes the manufacturing and testing of novel hybrid epoxy/carbon fibre composites with silica micro and poly-diallyldimethylammonium chloride-functionalised nanoparticles. A specific chemical dispersion procedure was applied using the poly-diallyldimethylammonium chloride to avoid clustering of the silica nanoparticles. The influence of the various manufacturing parameters, particles loading, and mechanical properties of the different phases has been investigated with a rigorous Design of Experiment technique based on a full factorial design (2131). Poly-diallyldimethylammonium chloride-functionalised silica nanoparticles were able to provide a homogenous dispersion, with a decrease of the apparent density and enhancement of the mechanical properties in the hybrid carbon fibre composites. Compared to undispersed carbon fibre composite laminates, the use of 2 wt% functionalised nanoparticles permitted to increase the flexural modulus by 47% and the flexural strength by 15%. The hybrid carbon fibre composites showed also an increase of the tensile modulus (9%) and tensile strength (5.6%).

The knowledge about anisotropy of wood possibility more security design of structures and structural members designed. Therefore, there are little quantity of results knowledge about shrinkage and anisotropy coefficients of Wood species, motivating the development of new researches. The aim of research is evaluate the possibility of estimate the full shrinkage (radial; tangential; volumetric), anisotropy coefficient and shrinkage coefficient (radial; tangential; volumetric), using polynomial regression models (linear; quadratic; cubic) and exponential, by density of five Wood species (Cedro Doce [C20]; Canafistula [C30]; Angelim Araroba [C40]; Mandioqueira [C50]; Angelim Vermelho [C60]), properly classifieds in five strength classes for dicotyledonous according Brazilian Standard ABNT NBR 7190:1997. The better results were from tangential and volumetric retractions both using exponentials functions, justified by lower values of variation coefficients, with coefficients values of determination adjusted ranging from 51 and 54%. Even considered significant to the regressions for the tangential and volumetric shrinkage by analysis of variance, but with adjusted coefficients of determination lower than 70%, news researches should realized with other Wood species, enabling find general expressions for estimating such properties using the knowledge of the density.

International audience; This work investigates the effects of ageing on autoclaved composites made with unidirectional prepreg epoxy and flax tape in environments with 50% and 100% of relative humidity. A Design of Experiment (DoE) has been used first to determine the effect of the ageing time (0,2, 4, 6, 8 and 16 days), type of bending (3-point and 4-point bending) and fibre orientation (longitudinal and transverse) on the water absorption and flexural properties of 50% saturated composites. A second experiment at 100% humidity has been also performed to further characterise the composites and to identify the equivalent ageing time that provides the mechanical behaviour of the 50% humidity samples after sixteen days. The water absorption and apparent porosity levels increase progressively with the ageing time, in particular for the case of transverse laminates; these features compromise the flexural properties of the composites. The laminates subjected to 4-point bending showed increased water absorption levels and improved flexural properties compared to the samples under 3-point bending. The flexural properties of flax composites at 50% humidity after 16 days are equivalent to those shown by composites immersed in water for less than one day.

Currently many works of art made of soapstone and recognized as cultural patrimony of humanity are in an advanced stage of degradation. Hence, it is necessary to interrupt this process and recover the deteriorated parts. Composite materials consisted of steatite particles and epoxy polymer are designed and characterised for their application in the repair of sculptures made of soapstone. The material applied in restorations should provide coloration and texture similar to soapstone besides structural requirements. The degree of similarity of the artificial material to the rock is enhanced by the proper selection of the particle size range and the increase of steatite incorporation in the composites. A statistical methodology based on the mixture design is used to optimize the relative amount of three particle size fractions of steatite particles in order to maximise the proportion of the dispersed phase in the composites. The maximum particle packing density (1.50 g/cm³) is obtained for a ternary mixture, composed of 62% of coarse particles (1.18 mm - 0.60 mm), 6% of medium sized particles (0.60 mm - 0.30 mm) and 32% of fine particles (0.30 mm - 0.15 mm). In this manner, the fabrication of composites based on an epoxy polymer matrix with 70wt% of incorporated steatite particles has been possible, increasing the maximum amount by 10% as used in previous works.

This work investigates the effect of using functionalised poly-diallyldimethylammonium chloride (PDDA) silica micro and nanoparticles on the apparent density, tensile and flexural strength and modulus of hybrid glass fibre reinforced composites. The work is carried out using a Design of Experiment (DoE) approach on a population of 60 composite specimens produced according the size of the nanoparticles and their weight fraction. A 2% of weight fraction of functionalised silica nanoparticles is shown to reduce the flexural strength and density of the composites, but to maximise significantly both the tensile, flexural modulus and tensile strength of the hybrid glass fibre materials.

Fibre metal laminates (FMLs) have been widely used to manufacture airframe components. This work describes novel sisal fibre reinforced aluminium laminates (SiRALs) that have been prepared by cold pressing techniques and tested under tensile, flexural and impact loading. The pristine sisal fabric and the sisal fibre reinforced composites (SFRCs) were also tested to understand the difference in mechanical performance of the sisal fibre metal laminates. The SiRALs achieved not only the highest modulus and strength, but also the highest specific properties. The mean specific tensile strength and modulus of the SIRALs reached increases of 132% and 267%, respectively, when compared to the sisal fibre reinforced composites (SFRCs). Moreover, the mean specific flexural strength and modulus of the SiRALs were significantly higher than SFRCs, revealing increases of 430% and 973%, respectively. A delamination fracture mode was noted for SiRALs under bending testing. The SiRALs can be considered promising and sustainable composite materials for structural and multifunctional applications.

Hybrid Glass Fibre Reinforced Composites (HGRFCs) made with unidirectional glass fibres and silica or cement microparticles inclusions were investigated in order to improve their performance under flexural and impact loadings. Two full factorial designs were conducted to evaluate (i) the effect of the particle weight fraction on the compressive modulus of epoxy polymer (2131) and (ii) the effect of the number of layers and type of particle (32) on the apparent density, flexural modulus and strength of HGFRCs. Composites with higher flexural properties were evaluated under impact loading via one-way analysis. TGA and FTIR analyses were used to verify the effect of ceramic particles within the polymeric phase. A microstructural analysis (SEM) was performed to verify the fracture mode and better assess the mechanical performance of HGFRCs.

In today's modern world the composite materials have been widely used not only for aerospace/aeronautics, but also automotive, sports and construction industries. The flexural strength of laminated composites depends on the characteristics of dispersive and matrix phases, considering the presence of tensile and co mpressive loadings. For this reason, the addition of particles into the matrix phase has been investigated to enhance its stiffness and consequently the elastic modulus of the composite. Th is work investigates a glassfibre co mposite reinforced with silicon carbide part icles. The following responses were evaluated: apparent density, water absorption, flexural strength, modulus of elasticity. The results were compared to those manufactured with no silicon carbide particles. It was observed that the silicon carbide particles provided the increase of the apparent density and flexu ral strength of the composites.