1,721,025 research outputs found
Thermal processes in lava flowing in an open channel
Full text linkIn this work, cooling and dynamics of liquid lava flowing inside a channel with rectangular cross section is modeled numerically. The purpose i to evaluate the heating of the solid edges that flank the lava channel due to th flow of lava after a given time interval. Lava rheology is dependent on temperatur and on strain rate by a power law function. The study couples dynamics and thermodynamics inside the channel where lava flows driven by the gravity force. Th problem is thermal inside the solid edges which enclose the lava channel. Numerical tests indicate that the solution of the thermo-dynamical problem is independent o the mesh
Una tecnica basata sull'uso delle funzioni di Green Empiriche per modellare la storia della velocità di rottura di un piccolo terremoto
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The identity landscape in the cataloging of scattered assets in the area of amelia
No full textA landscape is a place with peculiar characteristics, the result between men and nature interaction, which connotes it, both from the physical point of view and from the cultural perspective. The Umbrian countryside is teeming with historical and artistic references, still intact in their cultural value. The visitor immediately grasps this identity, this ancient history, but still alive and present, testifying in the stones and in the earth the experience of a rural and simple society. In order to document the conservation of these rural assets, the research has considered the drafting of descriptions, with meaningful pictures of the buildings, highlighting their characteristics of features and/or degradation. The cataloging of historical resources stands as a fundamental instrument for their restoration; it is a good opportunity to give a logical order to the vision of a landscape, able to connect information and create a systematic network of comparisons between common heritages
Orientations of seismic ruptures from P polarities and P pulse widths inversions: the Sellano (Umbria-Marche, Italy) case study
No full textFar-field boundary conditions in channeled lava flow with viscous dissipation
No full textCooling and dynamics of lava flowing in a rectangular channel driven by the gravity force is numerically modeled. The purpose is to evaluate the thermal process as a function of time involving the liquid lava in contact with the solid boundary that flanks lava. Lava rheology is dependent on temperature and strain rate according to a power law function. The model couples dynamics and thermodynamics inside the lava channel and describes the thermal evolution of the solid boundary enclosing the channel. Numerical tests indicate that the solution of the thermo-dynamical problem is independent of the mesh. The boundary condition at the ground and at the levees is treated assuming a solid boundary around the lava flow across which lava can exchange heat by conduction. A far field thermal boundary condition allows to overcome the assumption of constant temperature or constant heat flow as boundary conditions, providing more realistic results. The effect of viscous heating is evaluated and discussed.Cooling and dynamics of lava flowing in a rectangular channel driven by the gravity force is numerically modeled. The purpose is to evaluate the thermal process as a function of time involving the liquid lava in contact with the solid boundary that flanks lava. Lava rheology is dependent on temperature and strain rate according to a power law function. The model couples dynamics and thermodynamics inside the lava channel and describes the thermal evolution of the solid boundary enclosing the channel. Numerical tests indicate that the solution of the thermo-dynamical problem is independent of the mesh. The boundary condition at the ground and at the levees is treated assuming a solid boundary around the lava flow across which lava can exchange heat by conduction. A far field thermal boundary condition allows to overcome the assumption of constant temperature or constant heat flow as boundary conditions, providing more realistic results. The effect of viscous heating is evaluated and discussed
Relationship Between Depth of Seismicity and Heat Flow: The Case of the Gargano Area (Italy)
No full textWe consider a thermo-rheological model made of a viscoelastic half-space with Maxwell rheology and temperature-dependent viscosity. The half-space is made of layers with different values of density, thermal conductivity, activation energy and heat productivity. The model relates the surface heat flow to the depth of the brittle-ductile transition and the thickness of the seismogenic layer. The model is applied to the Gargano area (Italy) which is subject to a frequent low-magnitude seismic activity, although it lies out of the Apennine axis, which is the main Italian seismogenic area. The seismic activity in the Gargano area and surroundings occurs at depths that are systematically different in the north-eastern zone with respect to the south-western zone. In correspondence with the change in depth of earthquake foci, we observe a change in the value of surface heat flow. Starting from these observations and from the knowledge of the lithospheric structure, we propose two different geotherms for the two zones. Assuming a constant strain rate, the shear stress is computed as a function of depth and the thickness of the seismogenic layer in the two zones is inferred. The comparison of the results of the thermo-rheological model with the seismological observation is good
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
Local communities, Mediterranean desertification and demography: a reflection on permanent monitoring and mitigation policies
No full textThis study investigates the issue of green infrastructures in contemporary cities, adopting a strategic vision for increasingly complex metropolitan regions. Green infrastructures play an important role in ecological services and biodiversity preservation, improving significantly the quality of life of residents and visitors. The social dimension of gardens and parks at local (e.g. urban district) scale and green infrastructures at larger spatial scales is also addressed, fostering
the relationship between local communities and urban landscapes. With economic crisis, urban parks are increasingly considered a primary component of integrated strategies for urban regeneration with a bottom-up approach, addressing the demand for "natural landscape" in peri-urban areas. By recovering public spaces with social purposes and providing a comprehensive strategy for aesthetic improvement of common goods, the analyzed case studies give examples of specific measures for promoting environment-friendly urban regeneration strategies under place-specific social contexts
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