Classification(s) of Danielewski hypersurfaces

The Danielewski hypersurfaces are the hypersurfaces X Q,n in ${\mathbb{C}^3}$ defined by an equation of the form x n y = Q(x, z) where n ⩾ 1 and Q(x, z) is a polynomial such that Q(0, z) is of degree at least two. They were studied by many authors during the last twenty years. In the present article, we give their classification as algebraic varieties. We also give their classification up to automorphism of the ambient space. As a corollary, we obtain that every Danielewski hypersurface X Q,n with n ⩾ 2 admits at least two nonequivalent embeddings into $ {\mathbb{C}^3}

Counting Fiedler pencils with repetitions

We introduce a new notation based on diagrams to deal with Fiedler pencils with repetitions (FPR), and use it to solve several counting problems. In particular, we give explicit recurrences to count the number of FPRs of a given degree d, the number of symmetric, palindromic and antipalindromic ones (where the latter two structures are intended in the sense of [5]). We relate these structures to the presence of symmetries in the associated diagrams

Towards Automatic Crack Size Estimation with iFEM for Structural Health Monitoring

The inverse finite element method (iFEM) is a model-based technique to compute the displacement (and then the strain) field of a structure from strain measurements and a geometrical discretization of the same. Different literature works exploit the error between the numerically reconstructed strains and the experimental measurements to perform damage identification in a structural health monitoring framework. However, only damage detection and localization are performed, without attempting a proper damage size estimation. The latter could be based on machine learning techniques; however, an a priori definition of the damage conditions would be required. To overcome these limitations, the present work proposes a new approach in which the damage is systematically introduced in the iFEM model to minimize its discrepancy with respect to the physical structure. This is performed with a maximum likelihood estimation framework, where the most accurate damage scenario is selected among a series of different models. The proposed approach was experimentally verified on an aluminum plate subjected to fatigue crack propagation, which enables the creation of a digital twin of the structure itself. The strain field fed to the iFEM routine was experimentally measured with an optical backscatter reflectometry fiber and the methodology was validated with independent observations of lasers and the digital image correlation

Desenvolvimento e aplicação de procedimento metodológico em suporte ao planejamento participativo à redução de perda de solos em pequenas bacias hidrográficas com emprego da EUPS

A atividade agrosilvipastoril no Brasil e em diversas localidades do mundo, tem provocado impactos como a erosão do solo e o assoreamento dos corpos hídricos. A Equação Universal de Perda de Solos EUPS estima a perda de solos por erosão hídrica laminar (A) em ton/ha/ano, através da multiplicação de seis parâmetros: erosividade da chuva (R), erodibilidade do solo (K), comprimento da rampa (L), inclinação da rampa (S), uso e manejo do solo (C) e práticas conservacionistas (P). Dessa forma, ela permite a proposição de cenários alternativos de uso e manejo do solo através dos fatores C e P. Os Sistemas de Informações Geográficas SIG contribuíram muito para ampliação de sua aplicação. Resultados de pesquisa-extensão rural com enfoque sistêmico indicam, fundamentalmente, que as tecnologias de controle de erosão deveriam ser adaptadas às condições de cada tipo de agricultor e conduzidas diretamente nas suas propriedades, com a participação do mesmo. Com isso, esta pesquisa vem contribuir para gestão de bacias hidrográficas, visando redução de perda de solos e dos impactos conseqüentes, através do desenvolvimento de um procedimento metodológico participativo com base na utilização da EUPS e de SIG. Entre os temas e aspectos que serviram de maior embasamento para o desenvolvimento do procedimento metodológico têm-se: a estimativa da perda de solos sob duas abordagens em termos de modelagem convencional, sem o envolvimento de participação social, e contando com esta na determinação dos parâmetros C e P da EUPS; a mobilização de atores relevantes para participação do processo de modelagem subsídio quanto à definição dos fatores C e P; a capacitação dos participantes do processo de modelagem; a integração de saberes especializados e não especializados (locais); e a iteratividade como forma de aperfeiçoamento de processos. A aplicação do procedimento metodológico proposto a uma bacia hidrográfica piloto, situada no município de Itarana/ES, possibilitou mostrar que o mesmo pode auxiliar: no desenvolvimento de planejamento participativo para redução de perdas de solos de pequenas bacias hidrográficas com base na realidade de cada produtor rural, considerando, entre outros fatores, as especificidades sócio-culturais e a interação de saberes (especializados e não especializados locais); considerando a capacidade de investimento de cada produtor rural no dimensionamento dos investimentos institucionais adicionais, espaciais, necessários para o cumprimento de metas de redução de perdas de solo por bacia; que o maior esforço para aplicação da EUPS de forma participativa é compensado tanto pela produção de cenários de redução de perdas de solos mais realistas que os convencionalmente praticados como pela sensibilização e promoção do envolvimento dos produtores/ proprietários rurais em ações de conservação dos solos

Robust design optimisation of dynamical space systems

In this paper we present a novel approach to the optimisation of complex systems affected by epistemic uncertainty when system and uncertainty evolve dynamically with time; we propose a new modelling approach that uses Evidence Theory to capture epistemic uncertainty A system is considered which is affected by the time during the operational life (failure rate, performance degradation, function degradation, etc.). The goal is to obtain a resilient design: robust with respect to performance variability and reliable against possible partial failures of one or more components. We propose to enhance the Evidence Network Model (ENM) with time-dependent reliability functions and decompose the problem into subproblems of smaller complexity. Through this decomposition uncertainty quantification of complex systems becomes affordable for a range of real-world applications. The method is here applied to a simple resource allocation problem where the goal is to optimally position subsystems within a spacecraft [1

Dislocation-Actuated Growth and Inhibition of Hexagonal L-Cystine Crystallization at the Molecular Level

Crystallization of L-cystine is a critical process in the pathogenesis of kidney stone formation in cystinuria, a disorder affecting more than 20 000 individuals in the United States alone. In an effort to elucidate the crystallization of L-cystine and the mode of action of tailored growth inhibitors that may constitute effective therapies, real-time in situ atomic force microscopy has been used to investigate the surface micromorphology and growth kinetics of the {0001} faces of L-cystine at various supersaturations and concentrations of the growth inhibitor L-cystine dimethylester (CDME). Crystal growth is actuated by screw dislocations on the {0001} L-cystine surface, producing hexagonal spiral hillocks that are a consequence of six interlacing spirals of anisotropic molecular layers. The high level of elastic stress in the immediate vicinity around the dislocation line results in a decrease in the step velocities and a corresponding increase in the spacing of steps. The kinetic curves acquired in the presence of CDME conform to the classical Cabrera–Vermilyea model. Anomalous birefringence in the {101̅0} growth sectors, combined with computational modeling, supports a high fidelity of stereospecific binding of CDME, in a unique orientation, exclusively at one of the six crystallographically unique projections on the {1010} plane

Digital Technologies for Transport and Mobility: Challenges, Trends and Perspectives

This white paper aims at presenting the ideas emerging from the different fields pertaining to transport and mobility, to describe the capacities of current state-of-the-art digital technologies and the perspectives that are expected to shape the future of transport and mobility

Post-transplant events Combined administration of alpha-erythropoietin and filgrastim can improve the outcome and cost balance of autologous stem cell transplantation in patients with lymphoproliferative disorders

autologous transplantation; erythropoietin; engraftment kinetic