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<p> Carbon nanotubes (CNTs) are ideal candidates for the reinforcement of the matrix and interphase zone in polymer matrix composites (PMCs), due to their ability to more effectively bind the reinforcing fibers to the matrix material. This can lead to the enhancement of several critical composite properties &ndash; including interfacial shear strength and interlaminar fracture toughness &ndash; that are typically associated with a composite material&rsquo;s resistance to delamination. Direct dispersion of CNTs into the matrix of the composites has been shown to be very difficult. A more effective way to reinforce PMCs using CNTs is to grow CNTs directly on the reinforcing fibers. To this end, a novel technique used to grow CNTs directly on carbon fibers has been developed at The University of Alabama and Auburn University. This method, referred to as the PopTube Approach, uses microwave irradiation to grow CNTs at room temperature in air, without the need for inert gas protection or additional feed stock gases. The simple nature of the PopTube Approach lends itself to large-scale, high-yield manufacturing that can be done in a cost effective manner. However, before this technique is developed beyond the laboratory scale, its effectiveness as a route to produce CNT-reinforced composites must be evaluated in a comprehensive manner. The objective of this work is to do just that &ndash; characterize the mechanical properties of CNT-reinforced composites produced via the PopTube Approach. A systematic experimental program is carried out to provide a comprehensive assessment of the effects of the PopTube Approach on a wide range of composite mechanical properties. Results show that the PopTube Approach provides for enhanced resistance to delamination with respect to several different loading events. Fractography studies are used to qualitatively understand the mechanisms responsible for these improvements in delamination resistance on the micro-scale. Results also suggest that improvements in delamination resistance via CNT reinforcement may come at the expense of the tensile properties of PMCs &ndash; which gives rise to the conclusion that in practice, the degree and manner of CNT reinforcement in PMCs should be carefully considered on an application-by-application basis. Together, the collection of studies performed herein provides a wide-ranging quantitative and qualitative assessment of the effects of the PopTube Approach CNT reinforcement scheme on the mechanical properties and behavior of polymer matrix composites. </p><p>

Yes / The on-going COVID-19 pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS- CoV-2) has posed an extraordinary threat to global public health, wealth and well-being. As the carrier of human life and production, infrastructures need to be upgraded to mitigate and prevent the spread of viral diseases. Developing multifunctional/smart civil engineering materials to fight viruses is a promising approach to achieving this goal. In this perspective, the basic introduction on virus and its structure is provided. Then, the current design principles of antiviral materials and structures are examined. Subsequently, the possibility of developing active/passive antiviral civil engineering materials (including cementitious composites, ceramics, polymers and coatings) is proposed and envisaged. Finally, the future research needs and potential challenges to develop antiviral civil engineering materials are put forward. The proposed strategies to develop multifunctional/smart antiviral civil engineering materials will aid in the construction of smart infrastructures to prevent the spread viruses, thus improving human life and health as well as sustainability of human society. / The authors would like to thank the National Science Foundation of China (51978127, 52178188, and 51908103) and the Fundamental Research Funds for the Central Universities (DUT21RC(3)039) for providing funding to carry out this investigation.

O estudo da transferência conjunta de calor e humidade em meios porosos é uma tarefa importante para melhor conhecer e compreender o comportamento das paredes e dos materiais aplicados nos edifícios ao longo do tempo. A simulação numérica destes fenómenos é um bom auxiliar pois possibilita um conhecimento maior com um menor dispêndio de tempo, e consequentemente com menores custos envolvidos. Neste trabalho, o modelo de Luikov e Philip - De Vries, de transferência de calor e humidade em meios porosos, é tomado como referência, associada à formulação matemática definida por V. Peixoto de Freitas, para a elaboração de um programa de simulação numérica do comportamento de materiais quando sujeitas as gradientes de temperatura e humidade, para funcionar num computador pessoal em Ambiente Windows. Nesta aplicação apostou-se fundamentalmente nos sistemas de comunicação com o utilizador, quer ao nível da entrada de dados, que se pretende o mais intuitiva possível, quer ao nível da visualização dos resultados, com recurso a gráficos que permitem, num relance, abranger quase a totalidade dos elementos envolvidos na simulação. Foram feitas diversas simulações com vista à validação do programa, por comparação com casos disponíveis em bibliografia. Esta comparação permite considerar o programa TrHum 98 como uma ferramenta de simulação numérica da transferência de calor e humidade em materiais de construção, vocacionada para a análise de paredes. Tem ainda restrições ao nível da quantidade de materiais disponíveis e números de camadas da parede, aspectos que poderão ser ampliados em versões futuras. / Moisture and heat transfer in porous media studies are an important task to better know and understand the behaviour of building envelopes during time. Numerical analyses of this phenomena can be very helpful because make possible to know more about it with less time. In this work, we took Luikov and De Vries model of heat and moisture transfer, with the algorithm already established by V. Freitas on is computer program Trhumidade, and we made a Windows based new program for numerical simulation of construction materials behaviour under moisture and temperature gradients. This is an user friendly input program, with an graphical interface that gives an entire overview of the simulations conditions, with a single look. We made some simulations, first to establish the parameter sensibility factors, and then to study some real based situations.