The production of plastic packing grows worldwide, resulting in the accumulation of these materials in the environment due to improper disposal and problems related to degradation. Alternatively, composites produced with agricultural residues and filamentous fungi may exhibit physical and mechanical properties similar to or greater than expanded polystyrene, depending on the fungal species and substrate of the cultivation. In the literature, no reports were found on the use of coconut powder and edible fungi of white rot in the mechanical properties of composites. Thus, the objective of this work was to select fungal isolates and to evaluate the period of cultivation in the mechanical resistance of composites produced in coconut powder supplemented with wheat bran. The experimental design was completely randomized in a 5 x 3 factorial scheme corresponding to the cultivation of five edible fungal isolates (Pleurotus ostreatus: POS-W, POS-SP1, POS-98/38; Pleurotus eryngii: POS ER and Pycnoporus sanguineus: PS) and three culture periods after complete colonization of the substrate (15, 30 and 45 days), with four replications. The period of cultivation of the fungal isolates may influence in the composite mass loss and volume loss. The compressive strength and tenacity of the composite are influenced by the fungal isolate and the time of cultivation. The isolates of Pycnoporus sanguineus, Pleurotus ostreatus and P. eryngii present potential characteristics for the production of biodegradable composites.

The demand for biodegradable composite has grown worldwide in recent years, mainly in order to reduce environmental contamination by structural materials produced from the oil industry. The objective of this study was to evaluate the growth of isolates from the edible mushroom “Shiitake” (Lentinula edodes) in substrate coconut powder-based supplemented with wheat bran, as well as to analyze the influence of fungi growing period and drying time of the colonized substrate on the mechanical properties of the composite, in order to produce a biodegradable composite. The mycelial density is not influenced by the type of hyphae of L. edodes. Drying of the composite does not influence the residual odor, depending on the isolate. The compressive strength and foam type of the fungal composite may be influenced by the culture period and type of hyphae, depending on the fungal isolate. The composites colonized by the L. edodes isolates presented higher mechanical resistance at 30 days of complete colonization. The coconut powder supplemented with wheat bran colonized by isolated fungi LED 96/18 is an ecological alternative in the packaging production considering its mechanical properties.

The bolted joints sizing procedures shall adequately match the conditions imposed on the joint in service, to ensure high reliability designs. Therefore, this study aims to analyze the load distributions on the bolt when applying external load on bolted joints. Finite element and extensometry analyses as well as analytical calculations were performed in order to compare the magnitude of the joint overall stiffness, with respect to several available theories. The results acquired through the analytical method prescribed in the VDI 2230 standard as well as the finite element and extensometry analyses obtained great accordance. These results indicate that VDI 2230 standard adequately represents the mechanical behavior of the joint and should be used as a guideline for the reliable design of bolted joints subjected to the loading conditions of the present paper.

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O profissional de computação precisa adquirir as mais variadas habilidades para se manter competitivo no mercado de trabalho. Entre essas habilidades, as denominadas soft skills (ou habilidades não-técnicas) são atributos pessoais que permitem ao indivíduo desempenhar uma boa interação com o mundo ao seu redor. Nesse contexto, o Programa de Educação Tutorial (PET) surge como uma alternativa para desenvolver tais habilidades durante o ensino superior. No entanto, existem poucas análises sobre como um discente pode desenvolver soft skills durante a realização de atividades no âmbito do PET. Neste artigo, através de um formulário, foi obtida a percepção dos discentes sobre o impacto das atividades realizadas no PET para o desenvolvimento de soft skills, considerando o contexto do estado do Maranhão. Os resultados apontam para o impacto positivo das atividades do programa para este fim, além de identificar oportunidades de melhoria.

Recently, β Ti alloys have been extensively studied, due to their advantageous properties. β titanium alloys can exhibit lower elastic modulus and may be produced by elements that do not exhibit cytotoxicity, such as niobium, molybdenum and zirconium. This study aims to evaluate the correlation between cold working and solution heat treatment regarding to the microstructure and hardness of the Ti35Nb2.5Sn alloy. The alloy was arc melted in inert atmosphere and the ingots were hot rolled with 40% reduction. Axial compression samples were then cold worked with 40%, 70%, 80% and 90%. After the cold working, the samples were then divided into two groups. In half of them, solution and quenching treatment was performed. Microstructural characterization was achieved by optical microscopy and X-ray diffraction. Vickers microhardness tests were also evaluated. The microstructural characterization confirmed the presence of β, α" and ω phases. Cold working above 70% reduction provides the increase of microhardness, which can be attributed to the grain refinement and others microstructural features, as the amount of strain induced α", the amount of the ω phase-when it is present, and also by the dislocation density.

NiCr metal matrix composite reinforced with Cr3C2 particles can be applied as coating to various pieces of equipment, including those operating under fatigue. In the present study, the nanometric powder was obtained by high energy milling and sprayed by the high velocity oxygen fuel technique on ASTM A516 steel substrate. The comparison was made between the layer obtained from powders in nanometric scale, micrometric scale and mixing 50% of both. The coating thickness, hardness, microstructure, porosity and roughness were evaluated. Fatigue tests were performed on the three coatings in addition to the layer free substrate. The effect of coating morphology and its roughness on fatigue performance was studied. The surface roughness of the Nano coating was significantly lower than both of the other coatings. However, the three different layers that were tested did not experience significant differences in their fatigue performance. All three coatings had lower fatigue performance than the steel substrate. Article Comparative study of the fatigue performance of the micro and nanometric Cr 3 C 2-25NiCr coating sprayed by HVOF on ASTM A516 steel substrate

The aim of the present investigation is to evaluate the influence of the powder size of Cr3C2-25NiCr spraying powder on the fatigue behavior of HVOF-sprayed coating on the ASTM A516 steel substrate. Conventional commercial Cr3C2-25NiCr spraying powder was previously treated through high-energy milling. The crystallite sizes of milled powders were measured by X-ray diffraction and transmission electronic microscopy. Three different powder formats of the same Cr3C2-25NiCr composite were subjected to HVOF spraying to produce (i) a Milled-Coating (from high-energy milled spray powder), (ii) an Original-Coating (from conventional commercial spray powder), and (iii) a 50%–50% mixture of both (Milled + Original-Coating). The same spraying conditions were adopted for all the assessed cases. The sprayed coatings were investigated through the Knoop hardness test and SEM-EDS analysis. In addition, 3-point bending fatigue tests were conducted at different stress levels up to 107 cycles. The coating morphology and roughness effects on fatigue behavior were analyzed. The Cr3C2-25NiCr milled coating presented a lower fatigue life above the fatigue limit and a higher fatigue limit than other coatings; this outcome could be attributed to its lower surface roughness and finer grain size microstructure.