1,721,935 research outputs found
Additive manufacturing introduced substructure and computational determination of metamaterials parameters by means of the asymptotic homogenization
Get PDFMetamaterials exhibit materials response deviation from conventional elasticity. This phenomenon is captured by the generalized elasticity as a result of extending the theory at the expense of introducing additional parameters. These parameters are linked to internal length scales. Describing on a macroscopic level, a material possessing a substructure at a microscopic length scale calls for introducing additional constitutive parameters. Therefore, in principle, an asymptotic homogenization is feasible to determine these parameters given an accurate knowledge on the substructure. Especially in additive manufacturing, known under the infill ratio, topology optimization introduces a substructure leading to higher-order terms in mechanical response. Hence, weight reduction creates a metamaterial with an accurately known substructure. Herein, we develop a computational scheme using both scales for numerically identifying metamaterials parameters. As a specific example, we apply it on a honeycomb substructure and discuss the infill ratio. Such a computational approach is applicable to a wide class substructures and makes use of open-source codes; we make it publicly available for a transparent scientific exchange
Cultura organizacional y su influencia en la rentabilidad de la empresa Abali Contratistas S.A.C, Chiclayo 2018
Get PDFEl presente trabajo de investigación titulado Cultura organizacional y su influencia
en la rentabilidad de la empresa Abali Contratistas S.A.C., Chiclayo 2018, tuvo como
objetivo principal determinar la influencia de la cultura organizacional en la rentabilidad de
la empresa.
En cuanto a la metodología aplicada, el método es deductivo investigación
cuantitativa de tipo correlacional, descriptivo y básico, con un diseño no experimental y de
enfoque transversal. La muestra estuvo constituida por 10 trabajadores administrativos y
operativos de la empresa, así como también los datos de estados financieros durante los
años del 2016 y 2017. La técnica aplicada en el estudio fue la encuesta y el instrumento el
cuestionario.
Se concluye, que la cultura organizacional influye directamente en los factores que
involucran a la rentabilidad de la empresa Abali Contratista S.A.C., evidenciándose que la
empresa deficiencias en cultura organizacional de la empresa afectando el desempeño y la
productividad, lo que perjudica los niveles de inversión y recursos.Tesi
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
A benchmark strain gradient elasticity solution in two-dimensions for verifying computational approaches by means of the finite element method
Get PDFIn elasticity, microstructure-related deviations may be modeled by strain gradient elasticity. For so-called metamaterials, different implementations are possible for solving strain gradient elasticity problems numerically. Analytical solutions of simple problems are used to verify the numerical approach. We demonstrate such a case in a two-dimensional continuum as a benchmark case for computations. As strain gradient enforces higher regularity conditions in displacements, in the finite element method (FEM), the use of standard elements is often seen as inadequate. For such piecewise or elementwise continuous elements, we examine a possible remedy to correctly simulate strain gradient elasticity problems by implementing two techniques. First, we enforce continuity of displacement gradient across elements; second, we employ a mixed finite element method where displacement and its gradient are solved both as unknowns. The results show the pros and cons of each numerical technique. All methods converge monotonically, but the mixed method is more reliable than the other one
Commented translation of Erwin Schrödinger’s paper ‘On the dynamics of elastically coupled point systems’ (Zur Dynamik elastisch gekoppelter Punktsysteme)
No full textThe paper ‘Zur Dynamik elastisch gekoppelter Punktsysteme’ by Schrödinger (1914) does not seem to have attracted the attention that it deserves. We translate it into English here and we discuss its results in detail, with a view to its possible influence in the modern theories of generalised continua. The clever solution found, in terms of Bessel functions, by Schrödinger of the problem of the vibrations of a linear infinite chain of molecules gives some important methodological hints for contemporary research
Assessing plants resistant to heavy elements in the sewage soil of the construction waste recovery center of Gud Abali – Tehran
No full textIntroduction: Environmental pollution caused by growing dumps of increasing urban construction wastes has adverse effects on the health of the environment. This research was carried out with the aim of planting plants resistant to heavy elements in the construction waste recovery center of Gud Abali - Tehran.Material and methods: The research method, while laying the foundation of cognitive theory, was experimental-analytical, which was carried out cross-sectionally in 2022. The research samples are oleander (Nerium oleander), eucalyptus (Eucalyptus camaldulensis), bitter olive (Melia azedarach), Myrtus communis L., rose (Rosa damascena), pistachio (Pistacia vera) and pine (Pinus). They were randomly selected. Lands were selected based on the necessity of ten percent planting of plants around industrial factories according to the environmental regulations of the Environmental Organization and in the surrounding environment of the sand factory. The samples were planted in the effluent soil of the Abali Mining Center in Tehran and were kept under light and temperature conditions of 37 degrees during several months of care and irrigation. The measurement tool was objective observation, the validity of which was confirmed by experts and the reliability of plant growth criteria. Then the findings were analyzed using laboratory investigation and content analysis and SPSS software.Results and discussion: The findings showed that the increase in the concentration of heavy metals Cd and Pb in the sewage soil of the region causes a decrease in the diversity and density of plant species, and by managing the planning of plants resistant to heavy elements, the adverse effects of these elements on the diversity and density of vegetation in the region can be reduced. The findings showed that the eucalyptus plant did not grow at the beginning of the growing season due to the high absorption of heavy metals, but the oleander, bitter olive, case, rose, pistachio and pine plants continued to grow. Since it is not possible to expand the vegetation of Gud Abali area of Tehran without evaluating the resilience of resistant plant species to heavy elements of the region, the application of these findings in presenting the species planting pattern will lead to the biological instability of the land's vegetation.Conclusion: Assessing plants resistant to heavy elements can reduce the adverse effects of heavy elements on plant diversity and density in the region. In this regard, plant remediation is recommended in order to manage the concentration of heavy elements in the effluent soil of Gud Abali Construction Waste Recovery Center of Tehran
Theory and computation of higher gradient elasticity theories based on action principles
Get PDFIn continuum mechanics, there exists a unique theory for elasticity, which includes the first gradient of displacement. The corresponding generalization of elasticity is referred to as strain gradient elasticity or higher gradient theories, where the second and higher gradients of displacement are involved. Unfortunately, there is a lack of consensus among scientists how to achieve the generalization. Various suggestions were made, in order to compare or even verify these, we need a generic computational tool. In this paper, we follow an unusual but quite convenient way of formulation based on action principles. First, in order to present its benefits, we start with the action principle leading to the well-known form of elasticity theory and present a variational formulation in order to obtain a weak form. Second, we generalize elasticity and point out, in which term the suggested formalism differs. By using the same approach, we obtain a weak form for strain gradient elasticity. The weak forms for elasticity and for strain gradient elasticity are solved numerically by using open-source packages—by using the finite element method in space and finite difference method in time. We present some applications from elasticity as well as strain gradient elasticity and simulate the so-called size effect
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