IRIS - UNIRSM (Univ. degli Studi della Repubblica di San Marino)
Not a member yet
2115 research outputs found
Sort by
How to easily model doubly curved shells with variable radii of curvature
No full textThe studies of shell structures have always been a special topic in structural mechanics due to the complexity of shell geometries. Historically speaking, the first studies involved shallow shells, which include a small curvature effect. This theory can only be applied for shells of rectangular planforms and very high curvature with respect to the shell thickness. Later on, other researchers introduced the differential geometry to investigate thin shells, but generally this mathematical tool is introduced only to present a general framework of a wider problem. In fact, only shells with constant curvature are involved in most of the papers published in the last 70 years. It is very unusual to find works in which doubly-curved shells with variable radii of curvature are presented, mainly because their geometric description is not easy to implement with standard tools. This work aims to present a general framework which has its basis in the mathematical description of a doubly-curved thick body and can be easily solved by using a fast, accurate and reliable numerical tool termed Generalized Differential Quadrature (GDQ) method. The fundamental equations, which are needed to describe the geometry of doubly-curved shells with variable radii of curvature, will be presented. The same equations are discretized and numerically evaluated in order to obtain the geometric parameters of the same shell structures. All these details are essential for obtaining the equations of motions of such structures. It is remarked that no approximation is given on the normal vector (only limited to the discretization used for the GDQ method), because the shell geometric parameters are evaluated in all the discrete point on the actual shell surface. Therefore, the authors are able to mechanically investigate doubly-curved shell structures with variable radii of curvature. The structural theory employed in all the presented numerical applications is a higher order unified formulation, which is able to easily model any kind of first and higher order shear deformation theory for laminated composite shell structures
Italian Motherhood on Screen
No full textThis book is the first scholarly analysis that considers the specificity of situated experiences of the maternal from a variety of theoretical perspectives. From “Fertility Day” to “Family Day,” the concept of motherhood has been at the center of the public debate in contemporary Italy, partly in response to the perceived crisis of the family, the economic crisis, and the crisis of national identity, provoked by the forces of globalization and migration, secularization, and the instability of labor markets. Through essays by an international cohort of established and emerging scholars, this volume aims to read these shifts in cinematic terms. How does Italian cinema represent, negotiate, and elaborate changing definitions of motherhood in narrative, formal, and stylistic terms? The essays in this volume focus on the figures of working mothers, women who opt for a child-free adulthood, single mothers, ambivalent mothers, lost mothers, or imperfect mothers, who populate contemporary screen narratives
Fotografia e storia dell'emigrazione. Nota Introduttiva/Photography an History of Emigration. Introductory Note
No full textInstrumented test section for analyzing the curing process of cold-recycled mixtures
No full textAn instrumented pavement section was realized during the widening of an Italian motor- way in order to evaluate the curing process and performance of two types of cold-recycled mixtures: a cement treated material (3% of cement) and a cement-bitumen treated material (2% of cement and 3% of bitumen emulsion). The mixtures were fabricated in place by full-depth reclamation and, before the construction of the upper courses, the recycled layer was instrumented with pressure cells, asphalt strain gauges, time domain reflectometer probes and ther mistors. After construction, part of the recycled layer was sealed with bitumen emulsion in order to evaluate the effect of free or prevented water evaporation on the curing process. This paper describes the site preparation, the pavement construction phases, sen- sor installation and the setup of the data acquisition system. The moisture data recorded by the time domain reflectometer probes during 90 days are presented. Results show that moisture loss was higher for the cement treated material that was characterized by higher cement content. In addition, covering the layer with a bitumen emulsion membrane (i.e. preventing water evaporation) induced a marked reduction (around 50%) of the initial curing rat
Aree di conflitto e lavoro minorile: una sfida per il sistema educativo palestinese
No full textThe article aims to tackle the relationship between the phenomenon of child work and the Palestinianeducational reality starting from a first explorative investigation carried out within pilotschools involved in an international cooperation project, funded by the Italian Agency For DevelopmentCooperation. The schools involved have a very high percentage of working children. Thisinitial methodological phase of the survey has foreseen the integrated use of an “Index for inclusionand empowerment” questionnaire (inspired by the original Index for Inclusion), designed in theframework of the cooperation project by a group of researchers of the Department of EducationStudies of Bologna University, and the collection of life stories of working children. The interpretationof the first results, on the basis of the theoretical foundations of the Index instrument, ofthe main approaches to the phenomenon of child work in the international debate and the challengesposed by the context characterized by the dimension of the conflict, underlines the needto continue the research process on the fundamental characteristics of a Palestinian school ableto include working children through the introduction of cultural, organizational and didactical innovations
Linear static response of nanocomposite plates and shells reinforced by agglomerated carbon nanotubes
No full textThe static response of composite plates and shells reinforced by agglomerated nanoparticles made of Carbon Nanotubes (CNTs) is investigated in the present paper. A two-parameter agglomeration model is taken into account to describe the micromechanics of such particles, which show the tendency to agglomerate into spherical regions when scattered in a polymer matrix. From the macro mechanical point of view, the structures under consideration are characterized by a gradual variation of their mechanical properties along the thickness direction, since various distributions are employed to describe the volume fraction of the reinforcing phase. Several Higher-order Shear Deformation Theories (HSDTs) are taken into account and compared. The fundamental equations which govern the static problem in hand are solved numerically by means of the Generalized Differential Quadrature (GDQ) method. The variation of the agglomeration parameters, as well as the through-the-thickness profiles which describe the CNT volume fraction, are investigated to show the effect of the reinforcing phase on the static response of these nanocomposite plates and shells. In particular, a posteriori stress and strain recovery procedure is developed for these purposes. The current approach is validated through the comparison with the results available in the literature or obtained by a three-dimensional finite element model
