Obtenção de um modelo de elementos finitos simplificado para representação de juntas rebitadas em análise dinâmica de estruturas usando uma ferramenta de updating

ResumoNeste artigo é proposto um modelo de elementos finitos simplificado para representação de juntas rebitadas em análise dinâmica de estruturas. O rebite é modelado com elementos que combinam mola e amortecedor. Vários modelos numéricos são estudados com diferentes quantidades de rebites (um, 2, 3 e 5) e diferentes quantidades de elementos mola‐amortecedor (4, 6, 8, 12, 16 e 20) por cada rebite. Amostras constituídas por 2 placas de alumínio ligadas entre si por diferentes quantidades de rebites (um, 2, 3 e 5) são construídas e submetidas a análise modal experimental, a fim de serem conhecidas as suas características modais – frequências naturais e formas naturais de vibração. É usada uma metodologia de melhoramento de modelos de elementos finitos, também conhecido na linguagem anglo‐saxónica por updating, com o fim de obter a melhor representação numérica da junta rebitada relativamente às amostras experimentais. Uma avaliação da melhor representação numérica da junta rebitada é efetuada com base na comparação entre as frequências naturais experimentais e as frequências naturais numéricas, para cada modo de vibração, após aplicação do processo de melhoramento de elementos finitos. Mostra‐se que o modelo de junta composto por 8 e 12 elementos mola‐amortecedor por rebite consegue uma melhor aproximação ao comportamento dinâmico observado experimentalmente. Um valor numérico da constante de rigidez é obtido para as juntas em estudo.AbstractIn this paper, a simplified finite element model to represent a riveted lap joint in structural dynamic analysis field is proposed. The rivet is modeled by spring‐damper combination elements. Several numerical models are studied with different quantities of rivets (1, 2, 3 and 5) and spring‐damper combination elements (4, 6, 8, 12, 16 and 20) per rivet. Experimental samples of two aluminum material plates connected by different quantities of rivets (1, 2, 3 and 5) are built and tested in order to be known its modal characteristics ‐ natural frequencies and mode shapes. A finite element model updating methodology is used in order to get the best numerical riveted lap joint representation relatively to the experimental samples. An evaluation of the best numerical riveted lap joint is carried out based on the comparison between the experimental and numerical resonance frequencies after updating. It is shown that the riveted lap joints composed by eight and twelve spring‐damper combination elements per rivet have the best representation. A stiffness constant value is obtained for the riveted lap joints in stud

Nata organisms: an overview on the fermentative microbial ecosystem

Publicado em "Abstracts of papers - American Chemical Society", vol. 245The Acetobacter and Gluconacetobacter genus (both from the Acetobacteraceae family) are the most notable acetic acid producers, their intermediate metabolites being exploited biotechnologicaly for the production of vinegar, Kombucha, cocoa and nata de coco. Extensive efforts are being made to better understand the dynamic interplay of microbial populations during fermentation processes, with ample literature existing on virtually every food product currently being consumed. In the case of nata de coco, Gluconacetobacter strains have been found to play a key role in cellulose production. Despite abundant literature with isolated cellulose−producing strains, little work has been done in analysing population dynamics of the microbial communities. This presentation will address the microbial interplay in the production of nata de coco, with an overview of the taxonomy of the major acetic acid strains involved. An overview on the efforts and potential implications of upgrading nata de coco production through biotechnology will also be addressed

Bacterial cellulose from lab to market

Book of Abstracts of CEB Annual Meeting 2017Bacterial nanocellulose (BNC) is a nanofibrilar exopolysaccharide synthesized by certain Gram-negative, obligate aerobic, acetic acid bacteria, the Komagataeibacter genus being the most important due to the high cellulose yield obtained. The unique properties of this biopolymer have supported a wide range of potential applications, in human and veterinary medicine, odonthology, pharmaceutical industry, acoustic and filter membranes, biotechnological devices and in the food and paper industry. The largescale production of BNC, through advanced biotechnology has eluded many researches. Historical attempts but on low volume and high-value (mostly for biomedical applications) production can be traced back to the 90s. This presentation will show the main work with BNC by the Funcarb group. Examples of these studies will include the use of BNC in biomedical and food applications. Finally, an overview on the main efforts towards the production of BNC at large scale and potential markets will also be presented.info:eu-repo/semantics/publishedVersio

Bacterial NanoCellulose: what future?

Acetic acid bacteria (AAB) have been used in various fermentation processes. Of several ABB, the bacterial nanocellulose (BNC) producers, notably Komagataeibacter xylinus, appears as an interesting species, in large part because of their ability in the secretion of cellulose as nano/microfibrils. In fact, BNC is characterized by a native nanofibrillar structure, which may outperform the currently used celluloses in the food industry as a promising novel hydrocolloid additive. During the last couple of years, a number of companies worldwide have introduced some BNC-based products to the market. The main aim of this editorial is to underline the BNC potentials.info:eu-repo/semantics/publishedVersio

A spin-offs journey into achieving marketable products from bacterial cellulose

[Excerpt] Academic spin-offs, technological ventures born inside Universities, have increasingly strengthen the connections between the scholarship and the economy, by fostering the role of technology transfer and knowledge commercialization. This presentation will outline the major steps in taking an idea or a technology to market, growing the venture and aiming at securing a successful exit. Also, it will present BCTechnologies (Bacterial Cellulose Technologies), a spin-off from the University of Minho (Portugal). (...

Bacterial cellulose: from biotechnology to bio-economy

Bacterial cellulose (BC) is a nanofibrillar exopolysaccharide synthesized by certain Gramnegative, obligate aerobic, acetic acid bacteria, the Komagataeibacter genus being the most important due to the high cellulose yield obtained. The unique properties of this biopolymer have supported a wide range of potential applications, in human and veterinary medicine, odontology, pharmaceutical industry, acoustic and filter membranes, biotechnological devices and in the food and paper industry. The large-scale production of BC, through advanced biotechnology has eluded many researches. Historical attempts but on low volume and highvalue (mostly for biomedical applications) production can be traced back to the 90s. This presentation will overview the potential uses of BC in several applications. Also, it will present Satisfibre, S.A., a spin-off from the University of Minho (Portugal). Through R&D activities, networking & partnering with industry, Satisfibre aims to bring new and improved solutions, based on the use BC, to the food sector, biomedical, composites, pulp & paper and textile industries. Examples of successful product development and industry networking will be shown. Finally, an overview on the main efforts towards the production of BC at large scale and potential markets will also be presented.info:eu-repo/semantics/publishedVersio

Properties and recycling of covalently immobilized glycanases used for aqueous enzyme assisted Rosa mosqueta oil extraction

2nd International Conference on Protein Stabilisation - From Molecular Interpretation to Bio-Industrial Applicationsinfo:eu-repo/semantics/publishedVersio