188 research outputs found
Welding with high power fiber lasers - A preliminary study.
No full textThe new generation of high power fiber lasers presents several benefits for industrial purposes, namely high power with low beam divergence, flexible beam delivery, low maintenance costs, high efficiency and compact size. This paper presents a brief review of the development of high power lasers, and presents initial data on welding of API 5L: X100 pipeline steel with an 8 kW fiber laser. Weld bead geometry was evaluated and transition between conduction and deep penetration welding modes was investigated
Heated Chamber Winding of Thermoplastic Powder Impregnated Composites - Part I: Technology and Basic Thermo-Chemical Aspects
No full textApplicazioni di ragioneria -Elementi di computisteria, rilevazioni contabili e rappresentazione in bilancio
No full textHeated Chamber Winding of Thermoplastic Powder Impregnated Composites - Part II: Influence of Impregnation Degree on Mechanical Properties
No full text
Growth of a flexible fibre in a deformable ring
No full textWe study the equilibrium configurations related to the growth of an elastic fibre in a confining flexible ring. This system represents a paradigm for a variety of biological, medical, and engineering problems. We consider a simplified geometry in which initially the container is a circular ring of radius R. Quasi-static growth is then studied by solving the equilibrium equations as the fibre length l increases, starting from l = 2R. Considering both the fibre and the ring as inextensible and unshearable, we find that beyond a critical length, which depends on the relative bending stiffness, the fibre buckles. Furthermore, as the fibre grows further it folds, distorting the ring until it induces a break in mirror symmetry at l > 2 pi R. We get that the equilibrium shapes depend only on two dimensionless parameters: the length ratio mu = l/R and the bending stiffnesses ratio kappa. These findings are also supported by finite element simulation. Finally we experimentally validate the theoretical results showing a very good quantitative prediction of the observed buckling and folding regimes at variable geometrical parameters
Avvicinarsi agli antenati. Tradizione orale e autorità nel paese Anno
No full textAbstract
In this article the author deals with a less explored aspect of oral tradition in Africa, namely its relations to the definition of social categories based on age and gender. Using the conceptual framework of Pascal Boyer’s theory of tradition, criterias of legitimation and enablement regarding utterances of “traditional truth” in the Anno society are investigated. The study shows how the uttering of truth concerning the past, as well as the exclusive right of the elders to utter such truth, is not based on their mastery of a definite corpus of knowledge. What elders really master is an undisputed control over the reality which traditional utterances about the past refer to: the world of ancestors, a world which they are considered to be linked to through an “essential” quality attributed to their person
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