RGD-bases metal organic frameworks for selective delivery of therapeutics to tumor vasculature

Dissertação de mestrado integrado. Mestrado Integrado em Bioengenharia. Faculdade de Engenharia. Universidade do Porto. 201

Numerical Analysis of a Single Droplet Impinging upon Liquid Films using the VOF Method

Over the last few decades, developing alternatives to fossil fuels has become increasingly important. Biofuels, in particular, have attracted interest not only as an alternative to expensive fossil fuels but also by providing a solution to several challenges that the modern world currently faces, which include worries regarding energy security, economic development, the need to mitigate climate change and achieving lower greenhouse gas emissions. The major objective of this dissertation is numerically simulating the vertical impact of a single droplet upon a liquid surface with the same liquid properties and surrounded by air. Four fluids were taken into account: water, 100% Jet A-1 and 75%/25% and 50%/50% of Jet A-1 and NEXBTL, respectively. Particularly, multiphase flows are complicated phenomena in nature due to the difficulty in accurately predicting the interface between the phases. The numerical model consists of solving the Navier-Stokes equations by means of the explicit Volume of Fluid (VOF) method for a 2D axisymmetric assumption. This analysis considers several parameters and models that define this phenomenon. The physical properties of the liquid and gas, which are density and viscosity, surface tension, gravity and the contact angles of the different fluids represent our physical model. For the solution approach, the Fractional Step Method (FSM) numerically solves the Navier-Stokes incompressible equations, the Geometric Reconstruction scheme tracks the interface between the liquid and the gas phase and the Continuum Surface Force (CSF) model includes the effects of surface tension. The numerical results are validated both qualitatively and quantitatively with available experimental results. Six different outcomes were numerically simulated: Prompt Splash, Crown Splash, Spreading, Jetting, Fingering and Bubbling. The numerical results for the initial four outcomes are in good agreement with the experimental results in terms of the initial impact and crown expansion. The fingering phenomenon displayed several issues concerning crown development due to the 3D nature of the instabilities formed at the crown rim. The bubbling phenomenon was not possible to numerically recreate. Information regarding the dynamics of this phenomenon is scarce and more research is required to understand the peculiarities of dome formation. It was also visualized prompt splash for the crown splash and bubbling initial stages, which did not correspond to the experimental results. There are several reasons that justify this discrepancy, such as the difficulty in capturing very tiny ejected droplets or the solution approach forcing prompt splash on some of the cases. Overall, 3D simulations are required for future analysis to accurately predict secondary atomization. Work toward the bubbling phenomenon must also be considered.Nas últimas décadas, o desenvolvimento de alternativas aos combustíveis fósseis tem-se tornado gradualmente mais relevante. Os biocombustíveis, em particular, atraem interesse, não apenas como uma alternativa ao elevado custo dos combustíveis fósseis, mas também como solução para vários desafios que o mundo moderno enfrenta atualmente. Estes desafios incluem preocupações com a segurança energética, desenvolvimento económico, a necessidade de mitigar a mudança climática e redução das emissões de gases de efeito de estufa. O principal objetivo desta dissertação é simular numericamente o impacto vertical de uma gota sobre uma superfície líquida com iguais propriedades e envolvida por ar. Foram considerados quatro fluidos: água, 100% Jet A-1 e 75%/25% e 50%/50% de Jet A-1 e NEXBTL, respectivamente. Particularmente, os modelos multifásicos são fenómenos complicados na natureza devido à dificuldade em prever, com precisão, a interface entre as diferentes fases. O modelo numérico consiste em resolver as equações de Navier-Stokes a partir do método explícito do Volume de Fluido (do inglês, Volume of Fluid) para um modelo bidimensional (2D) axissimétrico. Esta análise considera vários parâmetros e métodos para caracterizar a dinâmica do impacto de gotas. As propriedades físicas dos fluidos, a gravidade e os ângulos de contacto são utilizados para clarificar este modelo. Em termos de abordagem dos métodos de solução, o Método de Etapa Fracionária (em inglês, Fractional Step Method) resolve numericamente as equações incompressíveis de Navier-Stokes, o esquema de Reconstrução Geométrica (em inglês, Geometric Reconstruction) delimita a interface entre o líquido e a gás e o modelo de Força de Superfície Contínua (em inglês, Continuum Surface Force) inclui os efeitos da tensão superficial. Os resultados numéricos são validados qualitativa e quantitativamente com os resultados experimentais disponíveis. Seis cenários diferentes foram simulados numericamente: Prompt Splash, Crown Splash, Spreading, Jetting, Fingering e Bubbling. Os primeiros quatro fenómenos referidos estão de acordo com os resultados experimentais em termos do impacto inicial e da expansão da coroa. O fenómeno de fingering apresentou vários problemas relativos ao desenvolvimento da coroa devido à natureza tridimensional (3D) das instabilidades formadas nos limites externos da coroa. O fenómeno de bubbling não foi possível de recriar numericamente. É necessário compreender a dinâmica deste fenómeno e como, atualmente, a pesquisa atual é escassa, estudos devem ser feitos para entender as peculiaridades da formação deste tipo de cúpulas. Também foi visualizado a ocorrência de prompt splash para as fases iniciais do crown splash e do bubbling, que não correspondiam aos resultados experimentais. Há várias razões que justificam essa discrepância, como a dificuldade de capturar as gotas extremamente pequenas provenientes da atomização secundária ou os métodos de solução forçarem o splash inicial em alguns casos. Em termos de análises futuras, simulações 3D são necessárias para averiguar o número, tamanho e velocidade das gotas provenientes da atomização secundária. O fenómeno de bubbling também requer um estudo mais exaustivo no comportamento da dinâmica do impacto das gotas

Influence of infill on the cyclic behaviour of traditional half-timbered walls

Half-timbered buildings represent an important historical heritage in many countries. They are diffused in various regions for different reasons, such as availability of materials, to lighten a structure, low cost and the strength they offer, and as a construction element able to resist seismic actions. This latter issue is the research topic analysed here, as half-timbered buildings have been specifically used in reconstruction plans as earthquake-resistant buildings in many countries, such as Portugal, India, Greece, etc. The aim of this paper is to study the behaviour under cyclic loading of such half-timbered walls, with typical connections, materials and geometries encountered in existing buildings. Traditionally, different types of infill could be applied to half-timbered walls depending on the country, namely brick masonry, rubble masonry, hay, mud, etc. The focus of this paper is to study and compare the seismic behaviour of the walls considering two different infill typologies, as well as the possibility of having no infill, i.e. considering only the timber frame. Cyclic test were performed on traditional walls and their behaviour was studied in terms of ultimate capacity, deformability, energy dissipation and stiffness.Fundação para a Ciência e a Tecnologia (FCT

Semantic Modelling of Plans and Execution Traces for Enhancing Transparency of IoT Systems

The work described here was funded by the award made by the RCUK Digital Economy programme to the University of Aberdeen (EP/N028074/1), a SICSA PECE travel award, the Defense Advanced Research Projects Agency with award W911NF-18-1-0027, the SIMPLEX program with award W911NF-15-1-0555 and from the National Institutes of Health under awards 1U01CA196387 and 1R01GM117097.Postprin

Experimental shear behavior of stone masonry joints

The mechanical characterization of the shear strength properties takes a major role on the evaluation of the lateral strength of masonry shear walls by means of simplified methods or when numerical analysis based on micromodelling approach is to be followed. Thus, the present paper presents an overview of the results obtained from direct shear tests of different types of masonry joints: dry and mortar masonry joints. Besides the shear strength parameters, a good insight was achieved in the evaluation of the complete shear stress-shear load displacement diagrams.info:eu-repo/semantics/publishedVersio

Comparison of Commercial and Open-Source CFD Solvers on Surface Tension Dominated Flows

Problems involving multiphase flows require a physical understanding of how the phenomenadevelop and the specific interactions they manifest. For surface tension relevant flows, suchas bubbles and droplets, the importance of modelling and predicting small-scale behaviouris crucial in accurately defining the liquid-gas interface and complex interactions that may takeplace. Axisymmetric numerical simulations of single droplets impacting onto thin liquid films areperformed using commercial and open-source CFD codes. ANSYS Fluent®is the commercialsoftware employed, whereas Basilisk is the open-source CFD solver adopted. The incompress-ible Navier-Stokes equations are coupled and handled differently throughout each software.A solution-adaptive mesh refinement tool is adopted to reduce computational cost. Softwarecomparison is based on quantitative and qualitative analysis, namely crown height and outerdiameter measurements, and the crown curvature and occurrence of splashing, respectively.Results show that Basilisk simulations are in good agreement with the experimental data. Fluent follows the tendency for the crown outer diameter however, in terms of height, the modelunder-predicts its growth and collapses at later stages of the impact for lower thicknessesFundação para a Ciência e a Tecnologiainfo:eu-repo/semantics/publishedVersio

Intellectual property challenges for the roads of innovation in Brazil

Abstract Purpose – This paper aims to present reflections and points of interest on the performance of Brazil and highlight the advances and challenges in relation to the intellectual property (IP) system; the authors highlight some scientific, economic and technological indicators on the main IP objects registered in the National Industrial Property of Brazil (INPI). Design/methodology/approach – A structured literature reviews the main indicators of IP of Brazil (2013-2017), related to the scientific and economic factors more evidenced in the global scenario, with emphasis on the investment of national GDP in R&D activities, the allocation of resources from the government sector and private initiative, as in other emerging economies, such as the BRICS. Findings – Despite Brazil’s progressive efforts to achieve greater efficiency in the public IP management system, GDP investment in R&D activities for 2019 is still below the OECD average of 2.3 per cent, and the IP indicators in the areas of patent registration, industrial designs and technology contracts have been declining. Research limitations/implications – Because of the difference between the laws of the countries on IP rights, the more incisive comparison could not be established among the emerging economies, highlighting the need for a standardization between the different international legislations. Originality/value – In the scientific field, this paper allows understanding the performance of the Brazilian IP system, and the categories that require greater investments, strengthen the IP culture and stimulate integration between the international IP systems, as it is a recurrent discussion in different research studies. Originally, the paper brought together economic and scientific indicators going beyond the traditional approach that deals with IP only restricting to the quantitative of patents