Multi-material additive manufacturing for advanced high-tech components

Multi-Material Additive Manufacturing for Advanced High-Tech Components is a new open Special Issue of Materials, which aims to publish original and review papers regarding new scientific and applied research and make great contributions to finding, exploring and understanding novel multi-material components via additive manufacturing [...]Project Moedinov—New aesthetics for collection coins by using advanced technologies with the reference POCI-01-0247-FEDER-033361

Using multiple regression, neural networks and support vector machines to predict lamb carcasses composition

The objective of this work was to use a Data Mining (DM) approach to predict, using as predictors the car- cass measurements taken at slaughter line, the compo- sition of lamb carcasses. One hundred and twenty five lambs of Churra Galega Braganc ̧ana breed were slaugh- tered.During carcasses quartering, a caliper was used to perform subcutaneous fat measurements, over the max- imum depth of longissimus muscle (LM), between the 12th and 13th ribs (C12), and between the 1st and 2nd lumbar vertebrae (C1). The Muscle (MP), Bone (BP), Subcutaneous Fat (SFP), Inter-Muscular Fat (IFP), and Kidney Knob and Channel Fat (KKCF) proportions of lamb carcasses were computed. We used the rminer R library and compared three regression techniques: Mul- tiple Regression (MR), Neural Networks (NN) and Sup- port Vector Machines (SVM). The SVM model provided the lowest relative absolute error for the prediction of BP, SFP and KKCF, while MR presented the best pre- dictions for MP and IFP. Also, a sensitivity analysis procedure revealed the C12 measurement as the most relevant predictor for all five carcass tissues

A particle swarm-based algorithm for optimization of multi-layered and graded dental ceramics

The thermal residual stresses (TRSs) generated owing to the cooling down from the processing temperature in layered ceramic systems can lead to crack formation as well as influence the bending stress distribution and the strength of the structure. The purpose of this study is to minimize the thermal residual and bending stresses in dental ceramics to enhance their strength as well as to prevent the structure failure. Analytical parametric models are developed to evaluate thermal residual stresses in zirconia-porcelain multi-layered and graded discs and to simulate the piston-on-ring test. To identify optimal designs of zirconia-based dental restorations, a particle swarm optimizer is also developed. The thickness of each interlayer and compositional distribution are referred to as design variables. The effect of layers number constituting the interlayer between two based materials on the performance of graded prosthetic systems is also investigated. The developed methodology is validated against results available in literature and a finite element model constructed in the present study. Three different cases are considered to determine the optimal design of graded prosthesis based on minimizing (a) TRSs; (b) bending stresses; and (c) both TRS and bending stresses. It is demonstrated that each layer thickness and composition profile have important contributions into the resulting stress field and magnitude.info:eu-repo/semantics/publishedVersio

Laser surface texturing of stainless-steel cutlery to integrate ceramic blocks: parametric optimization and patterning

Dynamic and fast-changing designs for cutleries or flatware are one important nature of this production business. Globalized hospitality merchandise, the demanding nature of modern customers, throat-to-throat competition of manufacturing industries, and the modernization of the manufacturing processes are some of the major challenges for the cutlery (silverware) manufacturing industry. So far, traditional methods of moulding and shaping are considered to be the best to provide static designs and trademark patterns of the organisation. Preparing a designed mould for a fixed blueprint of cutlery and then producing it in bulk is the sole purpose of existing methods. However, with the invention of laser engraving and design systems, the entire business of cutlery production has revolutionized. Allowing for different designs for different cutleries to set without changing the whole production line was the aim of this study. As shown in Figure 1, AISI-304 stainless steel, which is the general flatware material selected for laser engraving, was evaluated with three most vital input parameters (power, scanning speed and loops or number of passes) followed by the analysis of geometry, roughness, and volume removed/material removal (MR) as output variables. This study will provide insight into the know-how situation involving the processing of cutleries and introduction of different ceramic materials to the surface to define desired patterns. We produced different design patterns by laser and ingrained ceramic blocks on the silverware. This approach is much more flexible and adoptable for pattern changes. Besides that, there is no need to prepare a mould for each design. Belo Inox, Portugal supplied the silverware as per the collaborative project agreement.publishe

Nature inspired wet adhesive E-Skin patch for biosensing applications

Tree frogs are able to climb or stick to wet and rough surfaces. The hexagonal epithelial cells enclosed by profound passages which shield the surface of each toe pad and the array of nano-pillars on their surface are the main reason for their outstanding reversible adhesion in wet and rough environment. Inspired by the frog toe pad hexagonal hierarchical micro-pillars are developed by using Silicon rubber/ZrO2 nanocomposite. Due to the addition of oxide nanoparticles wettability properties of the rubber enhanced. The interlocking structures and hexagonal pattern helps to improve the capillary action and the sweat/water particles are drained easily, as a result surface adhesion increases. To design the hexagonal micro-pillars innovative laser engraving technique is adopted. The homogeneous distribution of nanoparticles and hierarchical hexagonal micro-patterns are confirmed through SEM analysis. This innovative design approach is helpful to design E-skin adhesive wearable devices for accurate monitoring of physiological signals.This work is supported by National Funds through the Portuguese Science Foundation (FCT) within project “FCT Reference No.: 030353 of IC&DT - AAC No. 02 / SAICT / 2017”, co-financed by the European Regional Development Fund (ERDF), through the Operational Programme for Competitiveness and Internationalization (COMPETE 2020), under Portugal 2020. Finally, this work was supported by FCT national funds, under the national support to R&D units grant, through the reference projects UIDB/04436/2020 and UIDP/04436/2020

Hydrothermal ageing behavior of bioinspired material with piezoelectric functions for implant applications

Implant-bone fixation loss can occur 10-15 years after surgery. This is related to bone resorption and consecutive biofilm formation in the generated gap, which could lead to tissues inflammation and implant loss [1]. Current solutions are focused on primary osseointegration for implant early survival rate. In long term, they lose effectiveness due to implant foreign body reaction once bone metabolism is challenged by a non-part of the body. Bone is composed of piezoelectric materials with production of biological electricity due to collagen deformation and displacement of the local electric field [2]. Barium titanate is a lead-free piezoelectric bioceramic without toxicological risk and absence of foreign body reactions that can mimic natural bone piezoelectricity and inhibit bacterial adhesion [3]. The focus of this work is design, produce, and characterize a smart, bio-inspired, and multi-functional composite material to improve implant long-term bone regeneration and antibacterial effect. In this sense, a composite with BaTiO3 particles and bioinert ZrO2 was produced. 5%BaTiO3-ZrO2 composites were mixed in isopropanol alcohol and ultrasonicated for total dispersion, followed by press (200MPa) and sintering technic (1300-1500ºC). The different samples were characterized with SEM (Fig1.(a)), that present two distinct phases, XRD analysis, and subjected to hydrothermal ageing (Fig1.(b)), to evaluate the stability of the tetragonal zirconia phase. After 5h of accelerated ageing (≈10 years), monoclinic phase is more evident with the sintering temperature increment, but always lower than 25%, staying in according with ISO 13356:200, promising to be promising a potential replacement material for implant applications.This work was supported by FCT national funds under the national support to R&D units grant, through the reference project UIDB/04436/2020, UIDP/04436/2020, FunImp POCI-01-0145-FEDER-030498 and through the grant 2021.09001.BD

A Sintaxe Harmónica Atonal no Espaço de Fourier: Para Uma Representação Esférica das Fases

Os arquétipos da sintaxe harmónica e a função que eles desempenham dentro da estrutura temporal da música tonal ocidental está amplamente sistematizada nos tratados da teoria da música. Por exemplo, a função que um acorde desempenha dentro das estruturas tonais é tipicamente reduzida a uma categorização tripla (tónica, subdominante e dominante) e cujo alinhamento temporal é bem estabelecido. Na música pós-tonal do início do século XX, este fenómeno é muito menos sistematizado e compreendido e evoluindo mesmo nos últimos anos para a existência de quase tantas teorias e sistemas de composição como o número de peças ou compositores. Neste contexto, avançamos alguns métodos e ferramentas dentro da musicologia computacional, que visa encontrar padrões sintáticos (ou seja, temporais) em estruturas harmónicas atonais. Para tal, seguimos métodos recentes de Yust sobre a utilização da informação de fase a partir da transformada discreta de Fourier. A nossa contribuição passa por uma representação esférica tridimensional resultante da informação de fase de dois coeficientes de magnitude para traçar as dimensões temporais dos conjuntos de classes de altura dentro de uma peça de música atonal. Os mapeamentos espaciais resultantes identificam automaticamente grupos de conteúdo intervalar semelhante e os padrões harmónicos típicos nos mesmos. Finalmente, para testar esta representação tridimensional, usamo-la para analisar a obra "Sechs kleine klavierstück", Op.19 de Arnold Schoenberg e como assistente do processo de composição, sugerindo padrões de movimento no material harmónico apresentado pelo compositor. Em resumo, pretendemos com este estudo: (1) traçar os conjuntos harmónicos do Op. 19 de Arnold Schoenberg num espaço tridimensional de acordo com o seu conteúdo intervalar; (2) agrupar esses conjuntos (3) identificar a existência de movimentos padronizados entre eles; (4) comparar os resultados da representação com análises anteriores e (5) avaliar a utilidade do sistema no processo criativo do compositor.Harmonic syntax archetypes and the function they play within the temporal structure of Western tonal music is vastly systematized across music theory treatises as rule-based principles. E.g., the function a chord plays within tonal structures is typically reduced to a threefold categorization (tonic, subdominant, and dominant), whose temporal alignment implies meaning. In post-tonal music since the early 20th century, this phenomenon is much less systematized and understood, evolving even in recent years, to the existence of almost as many theories and compositional systems as the number of composers or individuals works. In this context, we advance some methods and tools within computational musicology, which aims to unpack typical syntactic (i.e. temporal) patterns in atonal harmonic structures. To this end, we follow recent methods by Yust on the adoption of the phase information from the discrete Fourier transform (DFT) of pitch class sets. Our contribution extends previous research by proposing a three-dimensional spherical representation resulting from the phase information of two Z_12 magnitude-salient coefficients to plot the temporal dimensions of pitch class sets within an atonal music piece. Resulting spatial mappings automatically identify interval-content clusters and typical harmonic patterns across them. Finally, to test this three dimensional representation, we use it to analyze the "Sechs kleine klavierstück", Op.19 by Arnold Schoenberg and as an assistant to the composing process, suggesting movement patterns in the harmonic material presented by the composer. In summary, we intend with this study to: (1) plot the harmonic sets of Arnold Schoenberg's Op. 19 in a three-dimensional space according to its interval content; (2) group such sets into different clusters; (3) identify the existence of standardized movements between these clusters; (4) compare the results of the representation with previous analysis and (5) assess the utility of the system in the composer's creative process

Numerical simulation of capillary rise in millimetric cylindrical tubes

[Excerpt] Capillarity can be used in engineering nature-inspired slip-resistant surfaces, containing millimetric grooves, to provide an efficient grip on a solid floor with a small amount of liquid layer. Although literature has substantially reported analytical analysis and experimental data on capillary filling, numerical formulations provide the closest representation of the actual capillary filling process. Thus, in this work, a numerical model was developed to closely represent the natural filling of single-phase water inside a milli-metric-sized conduit of cylindrical shape, that demonstrates a single unit of the anti-slip surface matrix. A phase field numerical model was used to simulate the capillary imbibition of water inside the groove. [...]This work was supported by the Fundação para a Ciência e Tecnologia (FCT) project Bio Insole - Multi-Functional Bioinspired Slip Resistant Shoe-Sole (PTDC/EME-EME/7860/2020), and by the FCT reference projects UIDB/04436/2020 and UIDP/04436/2020. Susana O. Catarino thanks FCT for her contract funding provided through 2020.00215.CEECIND (DOI:10.54499/2020.00215.CEECIND/CP1600/CT0009

Multi‑mechanical waves against Alzheimer’s disease pathology: a systematic review

Alzheimer’s disease (AD) is the most common cause of dementia, affecting approximately 40 million people worldwide. The ineffectiveness of the available pharmacological treatments against AD has fostered researchers to focus on alternative strategies to overcome this challenge. Mechanical vibrations delivered in different stimulation modes have been associated with marked improvements in cognitive and physical performance in both demented and nondemented elderly. Some of the mechanical-based stimulation modalities in efforts are earlier whole-body vibration, transcranial ultrasound stimulation with microbubble injection, and more recently, auditory stimulation. However, there is a huge variety of treatment specifications, and in many cases, conflicting results are reported. In this review, a search on Scopus, PubMed, and Web of Science databases was performed, resulting in 37 papers . These studies suggest that mechanical vibrations delivered through different stimulation modes are effective in attenuating many parameters of AD pathology including functional connectivity and neuronal circuit integrity deficits in the brains of AD patients, as well as in subjects with cognitive decline and non-demented older adults. Despite the evolving preclinical and clinical evidence on these therapeutic modalities, their translation into clinical practice is not consolidated yet. Thus, this comprehensive and critical systematic review aims to address the most important gaps in the reviewed protocols and propose optimal regimens for future clinical application.FCT (Fundação para a Ciência e Tecnologia) through the grant with reference SFRH/BD/09375/2020, and in the scope of the projects UIDB/04436/2020, UIDP/04436/2020, and NORTE-01- 0145-FEDER-000023, funded by the European Fund for Regional Development (FEDER) of the Operational Programme for Competitiveness and Internationalization (POCI), by Portugal 2020

Novo método de avaliação dinâmica da articulação patelo-femoral em RM

A patologia patelo-femoral é uma das mais frequentes causas de consulta do joelho. A problemática desta articulação é reconhecidamente multifactorial. Apesar de estabelecidos vários factores de risco, tem sido globalmente assumida a necessidade de uma avaliação dinâmica e objectiva desta “articulação”, face a recorrentes erros diagnósticos. Revela-se essencial, quer no âmbito do diagnóstico, orientando a triagem patológica (e por conseguinte a escolha das terapias mais adequadas); quer ao nível do “follow-up” do paciente, nomeadamente para avaliação dos novos métodos cirúrgicos incluindo reconstruções do ligamento patelo-femoral medial (LPFM) para instabilidades objectivas. A hipótese deste estudo é que, da avaliação funcional dinâmica combinada com os factores morfológicos clássicos pode resultar a detecção de novos factores de risco e de avaliação funcional pós operatória da patelo-femoral