1,721,158 research outputs found
Stochastic Analysis of the free vibrations of an uncertain composite beam
No full textUniversity of Patras - Greec
Roll gap per rotation optimization in a radial ring rolling process
No full textIn this paper the authors tested the influence of the roll gap per rotation (RGpR) on different rings characterized by different ratio between ring width and height (W/H). The roll gap per rotation was identified by the ratio between the Idle roll feed and the angular velocity of the ring. In order to have a constant angular velocity of the ring the authors proposed an innovative approach designing a Driver roll speed law as a function of the ring diameter expansion to obtain a constant ring rotational speed and control the ring deformation. Under these constrains different Radial Ring Rolling processes have been simulated imposing three different level RGpR and W/H. Results have been analyzed by geometrical and physical point of view to identify the best set of RGpR and W/H. Based on the results a second numerical campaign have been simulated to test the effect of three set of ring angular velocities and Idle roll feed having the same RGpR. Results highlight interesting information to correctly produce a ring with lower forces and energies
rapid measurement of tryptophan, 5-hydroxytryptophan, serotonin and 5-hydroxy-indoleacetic acid in human CSF by selective fluorescence and HPLC.
No full textRing Rolling speed rolls optimization to improve ring quality and reduce production time
Full text linkIn this paper, an analysis of the production time reduction as a function of the Idle and Axial rolls speed law in a Ring Rolling process was examined. Starting from an industrial case study, the authors defined a new milling curve able to produce a better ring quality with lower loads. From this result, the authors tested the effect of the production time reduction till the 40% of the initial one. The Ide roll velocity was varied in a range between 0.71 and 1.13 mm/s while the Axial roll between 0.35 and 1.70 mm/s. Geometrical and load parameters have been taken into account to compare the results achieved. The authors identified in the external ring diameter and in the Idle roll maximum load the most critical parameter to control; in particular, a break-even point was determined in order to select a set of rolls speed laws able to produce a good quality ring with lower production time (about 20%) and lower loads (about 10 %). In this research both experimental and numerical approaches were followed
Behaviour of Hybrid Titanium Composite Laminate (HTCL) under in-plane loading
No full textThe Hybrid Titanium Composite Laminate (HTCL) incorporates the mechanical advantages of existing hybrid composite laminates such as ARALL and GLARE while extending their applications to harsh environments. Hybrid composite laminates, consisting of layers of Titanium Grade 2 foils bonded together with fibre-reinforced prepreg plies, have been tested under fatigue loading. HTCL has proven to possess exceptional strength and fatigue resistance. Degraded stiffness and ultimate resistances are provided through experimental stress-strain response of HTCL laminates, which are compared with predicted results by a laminate analysis code. The roles of mechanical degradation, the static and dynamic behaviour and fatigue properties of HTCL are addressed. The development of damage in HTCL specimens during fatigue is shown including titanium ply cracking, interfacial debonding, and layer failure. These tests provided several parameters in order to calibrate a numerical Lamaitre’s Continuous Damage Mechanics (CDM) fatigue model, which resulted in good agreement with experimental data. The influence of the fatigue properties of titanium layers on the fatigue of HTCL is discussed. The performance of HTCL laminates in fatigue is shown superior to that of the monolithic titanium alloy for room-temperature conditions.The Hybrid Titanium Composite Laminate (HTCL) incorporates the mechanical advantages of existing hybrid composite laminates such as ARALL and GLARE while extending their applications to harsh environments. Hybrid composite laminates, consisting of layers of Titanium Grade 2 foils bonded together with fibre-reinforced prepreg plies, have been tested under fatigue loading. HTCL has proven to possess exceptional strength and fatigue resistance. Degraded stiffness and ultimate resistances are provided through experimental stress-strain response of HTCL laminates, which are compared with predicted results by a laminate analysis code. The roles of mechanical degradation, the static and dynamic behaviour and fatigue properties of HTCL are addressed. The development of damage in HTCL specimens during fatigue is shown including titanium ply cracking, interfacial debonding, and layer failure. These tests provided several parameters in order to calibrate a numerical Lamaitre’s Continuous Damage Mechanics (CDM) fatigue model, which resulted in good agreement with experimental data. The influence of the fatigue properties of titanium layers on the fatigue of HTCL is discussed. The performance of HTCL laminates in fatigue is shown superior to that of the monolithic titanium alloy for room-temperature conditions
Rapid determination of tryptophan and its metabolites along the kinurenine pathway by HPLC.
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
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