197,190 research outputs found
Patrones de riqueza y distribución de peces en la cuenca Pilcomayo
No full textLa ictiofauna del Pilcomayo exhibe aún un conocimiento fragmentario habiendo predominado un enfoque de carácter descriptivo y orientado fundamentalmente a conocer la riqueza de especies existente y sus patrones de distribución. Como indican Sarmiento y Barrera (2004), el conocimiento de la diversidad de peces se ha concentrado en conocer la alfa diversidad. La información disponible es, en todo caso, dispar y difiere según el sector ...Fil: Baigún, Claudio Rafael M.. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación e Ingeniería Ambiental; ArgentinaFil: Minotti, Priscilla Gail. Universidad Nacional de San Martín. Instituto de Investigación e Ingeniería Ambiental. - Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación e Ingeniería Ambiental; Argentin
Deep Fracture Profile Effect on Dwt Test For Pipeline Characterization
No full textThe paper focuses on the fracture of a SENB specimen in a Drop Weight Tear Test. Deep fracture profile occurring during stable propagation is investigated.
Typically in the models that correlate the instrumented test results to CTOA values, the position of the fracture development is assumed straight, i.e. independent to specimen thickness. With this assumption in mind, the residual ligament computation is apparently easy. On the contrary, a remarkable fracture tunneling is present: it looks like different pipeline materials present a different attitude to crack tunneling.
In order to know the real shape of the fracture, silicone casts of DWTT fractured specimens were made when stable propagation is achieved. The casts are analyzed through tomographycal approach. Through the image processing of DWT tests, it is possible to automatically compute the angle of opening at the superficial crack tip during propagation as well as the overall kinematics during loading.
The attention is finally centered on two different steels used in inshore gas piping, X60 and X100, detailing the comparison on the effective stress field acting nearby the crack tip and the energy really involved for the fracture propagation.
The loads are applied making use of inclined constraints that allows to change the stress field ahead the crack tip, during the tests. As illustrated within the paper, the highest slopes allow to realize a persistent state of stress ahead the crack tip. This diffusive state of stress has an influence on X100 fracture behavior much more evident than that observed on X60
Propagazione di fratture longitudinali in gasdotti caratterizzati da bassa duttilità
No full textIl presente lavoro propone l’analisi di propagazione di una frattura fragile longitudinale di un gasdotto interrato basata sulla valutazione dell’energy release rate. Viene illustrata l’implementazione della suddetta metodologia all’interno di un codice proprietario agli elementi finiti con formulazione esplicita, illustrando gli interventi eseguiti sul preesistente algoritmo di propagazione stazionaria, e proponendo i risultati ottenuti a seguito di simulazioni dinamiche svolte su tubi in acciaio X80 e su provini SENB in pieno spessore sottoposti a prove DWTT
An Agent-based Programming Model for Developing Client-side Concurrent Web 2.0 Applications
No full textUsing the event-driven programming style of JavaScript to develop the concurrent and highly interactive clientside of Web 2.0 applications is showing more and more shortcomings in terms of engineering properties such as reusability and maintainability. Additional libraries, frameworks, and AJAX techniques do not help reduce the gap between the single-threaded JavaScript model and the concurrency needs of applications. We propose to exploit a different programming model based on a new agent-oriented abstraction layer, where first-class entities – namely agents and artifacts – can be used, respectively, to capture concurrency of activities and their interaction, and to represent tools and resources used by agents during their activities. We specialise the model in the context of client-side Web development, by characterising common domain agents and artifacts that form an extension of an existing programming framework. Finally, we design and implement a simple but
significant case study to showcase the capabilities of the model and verify the feasibility of the technology
Considerazioni sull'età scheletrica e sull'età dentale rispetto a quella cronologica in pazienti con morbo di Cooley
No full text
New experimental set-up to approach pipeline fracture behaviour by Three Point Bending Specimens
Full text linkThe work deals with the effective shape of the fracture during a Drop Weight Tear Test
(DWT). An inexpensive technique, able to determine the geometrical shape of the fracture,
is discussed and presented. The technique is capable to perform reliable measurements and
offers a mathematical description of the fracture profile. In few words, the fracture tunneling
measurement and its correlated effects are the objectives of this work. The technique is
based on a copy of the fracture by a silicone mold, followed by a digital analysis of the
tomographic images. The attention is finally focused on two different steels used in inshore
gas piping. The tunneling measurement is exploited in a finite element simulation of the
fracture propagation, thus opening the opportunity to update the kinematic models
applied for Crack Tip Opening Angle assessment
LES Simulation of CH4/air Microcombustor with Detailed Chemistry”, Combustion Science and Technology
No full textThe authors compare numerical simulations and experiments carried out on a swirling
methane/air cylindrical microcombustor with diameter and height 0.006m and 0.009 m,
respectively. They extend previous work, using LES and Flamelet methodology; here the
EDC finite rate model and the GRIMech 1.2 (32 species and 177 reactions) mechanism
are used. Gas temperature at the exhaust section, together with CH chemiluminescence
measurements and combustion efficiency analysis are provided. Results reproduce exhaust
temperature and combustion efficiency measurements, generally differing by less than 10%.
This work should be seen as an advance in the understanding of how to design future microcombustors,
presently under rapid development in particular for propulsion (e.g., for
UAVs) and microelectrical power generators
Developing Web Client Applications with JaCa-Web
No full textWe believe that agent-oriented programming lan- guages and multi-agent programming technologies provide an effective level of abstraction for tackling the design and pro- gramming of mainstream software applications, in particular those that involve the management of asynchronous events and concurrency. In this paper we support this claim in practice by discussing the use of a platform integrating two main agent programming technologies – Jason agent programming language and CArtAgO environment programming framework – to the development of Web Client applications. Following the cloud computing perspective, these kinds of applications will more and more replace desktop applications, exploiting the Web infrastructure as a common distributed operating system, raising however challenges that are not effectively tackled – we argue – by mainstream programming paradigms, such as the object- oriented one
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