174,238 research outputs found
C. Gildon, Vita di Thomas Betterton, traduzione, introduzione e note di Loretta Innocenti
No full textSocial Theatre. Brief Phenomenology of a Plural, Polycentric and Participatory Performativity
No full text“Social theatre” might sound like a tautology, since all “theatre” is “social” insofar as it is the art of bodies entering into a space-time relationship. The fact that the expression social theatre has been present in Italy since the end of the 1990s and been given a new meaning shows that the word theatre alone was perceived as insufficient to identify that set of participatory performance experiences, which, since the 1970s, had become increasingly widespread not only in practice, but also in national and international studies and awards, fully inscribing social theatre within the broader framework of applied performance.
The essay aims to give an overall picture of the situation of the social theatre in Italy, highlighting the complexity and resources within a plural, polycentric and participatory scenario
Recursive determination of conjugate profiles in planar motion with application to gear design
No full textA general procedure for determining the envelope of the outline of planar rigid figures is preseated which allows both local and finite undercutting to be taken into account. A suitable parametrization of the enveloped curves. together with the insertion of cusps wherever undercutting occurs, enables the procedure to be applied recursively while maintaining high accuracy in describing the resulting envelopes. The proposed procedure provides the basis for an original validat ion method regarding parallel-axis spur and helical gears. The method takes into account possible undercutting during hobbing or shaping. considers the desi red amount of meshing clearance over the entire tooth profile. and is able to detect meshing interference. Further, it provides a criterion in choosing the proper cutter profile. A numerical example showing the application of the method is discussed at the end of the paper
The Kinematics of Conical Involute Gear Hobbing
No full textThe paper is aimed at finding all relative rigid-body positions of two conical involute gears that mesh together with no backlash. The results are then specialized to determine two key setting parameters for a hobbing machine that has to cut a conical involute gear. A numerical example shows application of the presented results to a case study
Polynomial solution of the spatial burmester problem
No full textThe paper presents a new method for the dimensional synthesis of the spatial guidance linkage that features the guided body connected to the base by the interposition of five rods having spherical joints at both extremities. The linkage is required to index the guided body through seven arbitrarilychosen rigid-body positions. Core of the proposed method is an original algebraic elimination procedure that allows five unknowns to be dropped from a set of six second-order algebraic equations in six unknowns. As a result, a final univariate polynomial equation of twentieth order is obtained whose twenty roots, in the complex domain, represent as many possible placements for a connecting rod. A numerical example is reported
Position analysis of the tripod joint: An alternative approach
No full textThe position analysis, which is the most challenging phase of the kinematic analysis of a mechanism, was solved for the tripod joint, in exhaustive form, a few decades ago. The method proposed at the time was supposed to be able to find all possible assembly configurations of the joint. Regrettably, it becomes useless when the angle that parametrizes the position of one of the connected shafts reaches some specific values, which happens several times for each turn of the shaft; moreover, an error in the expression of a coefficient of a pivotal equation hampers adoption of the method. This paper presents a new procedure whose steepest step is finding the roots of a fourth order algebraic equation. It is shown that eight assembly configurations do exist for the adopted kinematic model of tripod joint, in the complex domain. The proposed procedure has a more direct approach than the previous one and is not affected by its singularities. Moreover, because no arbitrarily-selected movable reference frame is introduced, it leads to equations whose coefficients reveal the periodicity of the dependence of some parameters of the joint configuration on the angular position of one of the connected shafts. This means that some aspects of the tripod joint behavior can be hinted even without solving the equations. A numerical example shows application of the new procedure to a case study
Optimal Choice of the Shaft Angle for Involute Gear Hobbing
No full textWith reference to the machining of an involute spur or helical gear by the hobbing process, the paper suggests a new criterion for selecting the position of the hob axis relative to the gear axis. By adhering to the proposed criterion, the hob axis is set at the minimum distance from the gear axis, thus maximizing the depth of the tooth spaces of the gear. The new criterion is operatively implemented by solving a univariate equation, which stems from a new, synthetic analysis of the meshing of crossed-axis involute gears. A numerical example shows application of the suggested procedure to a case study and compares the optimal hob setting to the customary one
Presentazione
No full textIl presente articolo-presentazione descrive il volume Media Mutations e i contributi che vi compaiono. Questi ultimi sono ripartiti in quattro sezioni. La prima dedicata alla nozione di ecosistema narrativo (teorie e prospettive), una alle narrazioni mediali estese; una al rapporto tra ecosistemi e gli spettatori/utenti che li abitano; una all'analisi di alcuni studi di caso
Leucisca halimedophila Galil & Innocenti 2019, n. sp.
No full textLeucisca halimedophila n. sp. (Figs 2A, B, 4 A–C) Material examined. Holotype, male (9.2 x 11.8), MZUF-4446, Kenya, Watamu, reef, colls S. Cianfanelli, E. Talenti, G. Innocenti. Sept. 2000. Paratypes, 1 male (10.4 x 7.8), 1 young female (6.5 x 8.1), MZUF-4930. Description of holotype. Carapace transversely suboval in outline, about 1.3 times as wide as long, with greatly expanded branchial regions concealing ambulatory legs; dorsal surface smooth to the naked eye, margins lamellate, upcurved, closely and minutely granular, prominent conical protuberance medially (Fig. 2A). Front narrow, produced, upturned; margin slightly concave. Anterolateral margin rounded, continuous with posterior margins; posterior margin slightly wider than frontal margin, sinuous, bearing two flattened submedian lobes. Rounded median ridge running from front to conical gastrocardiac protuberance, culminating in cluster of flattened granules. Intestinal region with low protuberance medially. Epibranchial ridge rounded, inconspicuous, running obliquely from gastrocardiac protuberance to posterolateral margin. Ocular peduncle very short. Antennule folded into oblique fossa. Infraorbital margin with orbital hiatus closed by basal segment of antenna, distally with granulate pit. Anterolateral margin of buccal region raised, granulate, running parallel to anterolateral margin distally, notched on anterior margin. Third maxillipeds with margins of exopod and endopod closely granulate; endopod merus nearly as long as ischium along mesial margin, distally granulate; exopod slightly arcuate. Surfaces of pterygostomial, sub-hepatic and sub-branchial regions smooth, sparsely punctate. Cheliped slender. Merus trigonal, margins prominently granulate. Carpus globular, granulate; upper margin carinate. Palm laterally compressed, elongate, margins carinate, boldly granular; inner surface bearing a curving row of pearliform granules extending to dactylar articulation. Fingers short, bearing rows of granules extending to tips, tips crossing when closed. Ambulatory legs granulate, laterally compressed, similar in shape, gradually decreasing in length from first to fourth, hidden by extended branchial regions of carapace in dorsal view when retracted; meri unicarinate, carpi, propodi bicarinate on upper margins, meri bicarinate, propodi unicarinate on lower margins. Pleon with proximal two somites narrow, yoke-shaped; distal somites fused, bearing large triangular denticle subterminally; telson subtriangular (Fig. 2B). G1 (Fig. 4A,B) stocky, sinuous, distally setose, tip claw like. G2 short, filiform, tip laciniate (Fig. 4C). Colour (in life). Carapace, legs, bone colored; brown stripe running along median ridge from front to conic gastrocardiac protuberance, 3 brown dots on posterior margin (fide G. Innocenti). Etymology. The specific epithet, halimedophila, alludes to the carapace shape of the new species, which convincingly resembles a segment of dead coralline algae (Halimeda spp.). Used as an adjective. Distribution. Known from specimens collected from the type locality – Watamu, Kenya. Remarks. Leucisca halimedophila n. sp. resembles L. rubifera (Müller, l887) in the general outline of the carapace and chelipeds, and in possessing triangular denticle subterminally on male abdomen, but the present species is distinguished by a broader carapace, more prominent conic gastrocardiac protuberance, and less prominent intestinal protuberance than L. rubifera (Müller l887: tab. 4, fig. 4, 4a,b; Tirmizi & Kazmi 1979: fig. 3a,b; Naderloo 2017: fig. 14.20). The posterior margin is produced, bearing two flattened submedian lobes, rather than smoothly convex as in L. rubifera. The granulation on margins of the carapace, thoracic sternites, 3rd maxillipeds are much finer than in L. rubifera. Finally, G1 is stocky, sinuous, distally setose, and with a claw-like distal tip, rather than styliform as in L. rubifera (Tirmizi & Kazmi 1979: fig. 3c; Naderloo 2017: fig. 14.21c).Published as part of Galil, Bella S. & Innocenti, Gianna, 2019, Rare and new East African leucosiid crabs, pp. 139-145 in Zootaxa 4555 (1) on pages 140-142, DOI: 10.11646/zootaxa.4555.1.12, http://zenodo.org/record/262407
Analysis of meshing of beveloid gears
No full textThis paper analyses the meshing of a pair of beveloid gears mounted on intersecting or skew shafts. Precisely, the dependence of the backlash on the gear geometry and the shaft relative position are investigated. The study is preceded with the presentation of a new, basic nomenclature to describe the kinematically relevant dimensions of beveloid gears. Finally, a numerical example is reported. © 1997 Elsevier Science Ltd. All rights reserved
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