Insect-inspired acoustic micro-sensors

Micro-Electro Mechanical System (MEMS) microphones inspired by the remarkable phonotactic capability of Ormia ochracea offer the promise of microscale directional microphones with a greatly reduced need for post-processing of signals. Gravid Ormia ochracea females can locate their host cricket’s 5 kHz mating calls to an accuracy of less than 2° despite having a distance of approximately 500 µm between the ears. MEMS devices base on the principles of operation of O. ochracea’s hearing system have been well studied, however commercial implementation has proven challenging due to the system's reliance on carefully tailored ratios of stiffness and damping, which are difficult to realize in standard MEMS fabrication processes, necessitating a trade-off between wide-band operation and sensitivity. A survey of the variety of strategies that have been followed to address these inherent challenges is presented

Mechanical Modelling of single and collective cells behavior

Recent experimental results have suggested important direct implications of viscoelasticity of human cells and cell cytoskeleton dynamics on some relevant collective and at single-cell behaviors such as migration, adhesion, and morphogenesis. Other experimental studies have been performed on individual cancer and healthy cells of different types, demonstrating that the former were about 70% softer than the latter. In this thesis with the aim of characterizing — and gaining insights into — the frequency response of single-cell systems to mechanical stimuli (typically LITUS), a generalized viscoelastic paradigm which combines classical and spring-pot based (fractional derivative) models is presented. Than the modelling has been enriched considering the non-linear effect of the prestress, induced in protein filaments during cell adhesion and in the cell membrane (with a simple multiscale scheme that incorporates finite elasticity and a 3-D circus tent-like model), on the overall cell stiffness and finally determining its influence on the in-frequency response of the cell. The theoretical results have shown that the differences in stiffness — at least in principle — allow us to mechanically discriminate between tumor and normal cells: the critical frequencies associated with oscillation magnitude peaks (from tens to hundreds of kilohertz) could be helpfully utilized for targeting or ad hoc altering the functions of cancer cells. An experimental validation of the theoretical results is an ongoing work and the preparation of the experimental setup is also presented. In this thesis some first models have been presented to replicate in-vivo collective behavior of cells. Coherent angular rotation of epithelial cells has been reproduced by a cell-centered based mechanical model in which units are polarized, motile, and interact with the neighboring cells via harmonic forces. Starting from this model a continuum non-linear viscoelastic model incorporating the dynamics of liquid crystals has been studied and some preliminary numerical simulations have been performed

Proceedings of the 2018 Canadian Society for Mechanical Engineering (CSME) International Congress

Published proceedings of the 2018 Canadian Society for Mechanical Engineering (CSME) International Congress, hosted by York University, 27-30 May 2018

Towards a bio-shading system concept design methodology

Cities and buildings play a critical role in setting the conditions for human well-being while contributing to more just and environmentally conscious societies and economies. The design of environmentally and socially meaningful buildings has benefitted, in the past two decades, from scientific progress in the fields of computation and materials, as well as from a new way of looking into Nature as an inspirational example. This research focuses on the design of shading systems for building façades, assuming that biomimetics and computational design are a valid and proved combination. The main research question is how to develop architectural shading systems mimicking the adaptation strategies of Nature. The challenge is addressed by developing a design methodology for the creation and optimization of solar control systems based on the biological adaptive systems of terrestrial plants; creating a transfer and interpretation process of biological concepts to an architectural lexicon; and creating a universal methodology applicable to a diverse set of climatic, functional and local contexts. The research proposes a bioshading system design methodology, developed on a problem-based approach. Starting with the architectural challenge of design, solutions are sought in Nature to solve specific performance requirements of shading systems. The development of the methodology rests upon an informed process that integrates and interrelates three domains: architecture, Nature, and artifact. The ‘architecture’ domain is based on the conceptual process, the computational and parametric environmental analysis, and a diagnosis that informs the understanding of the performance requirements that need to be fulfilled. The ‘Nature’ domain is defined through an abstraction process: sustained by a mapping of plants’ features and adaptation strategies, the creation of a meme semantics triggers a performance-based design process. The ‘artifact’ domain is the physical materialization of the design concept, enabling its evaluation and emulation. The Nature-inspired design methodology developed in this research makes it possible for architects to solve the challenges of shading building façades, integrating local climate-related performance requirements with formal architectural criteria, using biomimicry as a mediator. In a step-by-step path, the user identifies specific project-related requirements, discovers and explores natural processes that guide inspiration, and conceptualizes a design proposal that is further simulated and prototyped.As cidades e os edifícios desempenham um papel crítico na definição das condições para o bem-estar humano, contribuindo para sociedades e economias mais justas e ambientalmente conscientes. O projeto de edifícios com significado ambiental e social beneficiou, nas últimas duas décadas, do progresso científico nos campos da computação e dos materiais, bem como de uma nova forma de encarar a natureza enquanto modelo inspirador. Esta investigação centra-se no design de sistemas de sombreamento para fachadas de edifícios, assumindo que a biomimética e o design computacional são uma combinação válida e comprovada. A principal questão de investigação é como desenvolver sistemas de sombreamento arquitetónicos mimetizando as estratégias de adaptação da natureza. O desafio é abordado através do desenvolvimento de uma metodologia de projeto para a criação e otimização de sistemas de controlo solar tendo por base os sistemas de adaptação biológicos das plantas vasculares terrestres; criação de um processo de transferência e interpretação de conceitos biológicos para um léxico arquitetónico; e criação uma metodologia universal aplicável a um conjunto diversificado de contextos climáticos, funcionais e locais. A presente investigação propõe uma metodologia de projeto de sistema bioshading, desenvolvida através de uma abordagem problem-based. Partindo do desafio arquitetónico de projeto, são procuradas soluções na natureza para resolver requisitos de desempenho específicos de sistemas de sombreamento. O desenvolvimento da metodologia tem por base um processo informado que integra e interrelaciona três domínios: arquitetura, Natureza e artefacto. O domínio 'arquitetura' tem por base o processo conceptual, na análise ambiental computacional e paramétrica e num diagnóstico que informa o entendimento dos requisitos de desempenho a serem cumpridos. O domínio 'Natureza' é definido por meio de um processo de abstração: sustentado por um mapeamento de recursos e estratégias de adaptação das plantas, a criação de uma semântica de memes desencadeia um processo de design com base no desempenho. O domínio "artefacto" é a materialização física do conceito de design, permitindo a sua avaliação e emulação. A metodologia de design inspirada na natureza desenvolvida neste trabalho de investigação possibilita aos arquitetos resolverem os desafios de sombreamento de fachadas de edifícios, integrando os requisitos locais de desempenho relacionados com o clima com critérios formais de arquitetura, usando a biomimética como mediadora. Num percurso progressivo evolutivo, o utilizador identifica requisitos específicos do projeto, descobre e explora processos naturais que orientam a inspiração e conceptualiza uma proposta de projeto que é simulada e prototipada

Computational Modelling of Concrete and Concrete Structures

Computational Modelling of Concrete and Concrete Structures contains the contributions to the EURO-C 2022 conference (Vienna, Austria, 23-26 May 2022). The papers review and discuss research advancements and assess the applicability and robustness of methods and models for the analysis and design of concrete, fibre-reinforced and prestressed concrete structures, as well as masonry structures. Recent developments include methods of machine learning, novel discretisation methods, probabilistic models, and consideration of a growing number of micro-structural aspects in multi-scale and multi-physics settings. In addition, trends towards the material scale with new fibres and 3D printable concretes, and life-cycle oriented models for ageing and durability of existing and new concrete infrastructure are clearly visible. Overall computational robustness of numerical predictions and mathematical rigour have further increased, accompanied by careful model validation based on respective experimental programmes. The book will serve as an important reference for both academics and professionals, stimulating new research directions in the field of computational modelling of concrete and its application to the analysis of concrete structures. EURO-C 2022 is the eighth edition of the EURO-C conference series after Innsbruck 1994, Bad Gastein 1998, St. Johann im Pongau 2003, Mayrhofen 2006, Schladming 2010, St. Anton am Arlberg 2014, and Bad Hofgastein 2018. The overarching focus of the conferences is on computational methods and numerical models for the analysis of concrete and concrete structures

Energy: A continuing bibliography with indexes

This bibliography lists 1169 reports, articles, and other documents introduced into the NASA scientific and technical information system from January 1, 1983 through March 31, 1983

Computational Modelling of Concrete and Concrete Structures

Computational Modelling of Concrete and Concrete Structures contains the contributions to the EURO-C 2022 conference (Vienna, Austria, 23-26 May 2022). The papers review and discuss research advancements and assess the applicability and robustness of methods and models for the analysis and design of concrete, fibre-reinforced and prestressed concrete structures, as well as masonry structures. Recent developments include methods of machine learning, novel discretisation methods, probabilistic models, and consideration of a growing number of micro-structural aspects in multi-scale and multi-physics settings. In addition, trends towards the material scale with new fibres and 3D printable concretes, and life-cycle oriented models for ageing and durability of existing and new concrete infrastructure are clearly visible. Overall computational robustness of numerical predictions and mathematical rigour have further increased, accompanied by careful model validation based on respective experimental programmes. The book will serve as an important reference for both academics and professionals, stimulating new research directions in the field of computational modelling of concrete and its application to the analysis of concrete structures. EURO-C 2022 is the eighth edition of the EURO-C conference series after Innsbruck 1994, Bad Gastein 1998, St. Johann im Pongau 2003, Mayrhofen 2006, Schladming 2010, St. Anton am Arlberg 2014, and Bad Hofgastein 2018. The overarching focus of the conferences is on computational methods and numerical models for the analysis of concrete and concrete structures