Urban space and social networks in times of crisis. A local perspective from the Exarchia neighbourhood of Athens

Δε διατίθεται περίληψη / no abstract availabl

finite element transient modelling for whole engine secondary air system thermomechanical analysis

Abstract This paper presents a new procedure developed in cooperation with Ansaldo Energia and aimed to predict metal temperatures in a gas turbine whole engine with an axisymmetric transient finite element approach. The 2D model includes a dedicated thermal fluid network where mass flow rates and pressure distributions are provided by external fluid network solvers in terms of time serie, while fluid-metal temperatures are computed through a customized version of CalculiX ® . This work represents a first insight about a fully integrated WEM ( Whole Engine Modelling ) procedure currently under development. The future implementation steps will be oriented to the usage of a customized version of the native CalculiX ® fluid network solver and the implementation of a system of monitoring and updating of the secondary air system (SAS) geometry. The aim is to progress from the current partly coupled approach with previously assessed mass flow and pressure distributions, to a fully integrated procedure able to take into account the interaction between the SAS fluid properties and the modifications in the geometry caused by mechanical and thermal loads. In this paper, the methodology will be presented introducing some details about the main modelling aspects and illustrating some preliminary results from the test of the procedure applied to a simplified model representative of a real engine geometry under transient conditions

Radiation-induced pneumonitis and fibrosis - Defining the role of immune cells and regulatory molecules

Radiation-induced pneumonitis and fibrosis still constitute a major complication in the treatment of patients with thorax-associated neoplasms. To date, the molecular mechanisms governing the onset and progression of these injuries are not entirely understood and no effective therapies are available. Aim of the present study was to gain more insight into the pathogenesis of radiation-induced pneumonitis and fibrosis, with the ultimate goal to provide a molecular basis for the development of novel and effective strategies for prevention or treatment of these pathologies. At this purpose, investigations on immune cells and on immunomodulatory molecules have been performed in vivo in a C57BL/6 mouse model of whole thorax irradiation with 15 Gray (Gy). In the present work, a novel immunoregulatory molecule was identified as a key mediator of radiation-induced fibrosis, in that mice deficient in this molecule showed no or minimal fibrosis at 30 weeks post irradiation (p.i.), while wild type (WT) mice showed extensive collagen deposition, and fibrotic areas positive for α-SMA and TGF-β at this time point. Thus, lack of this molecule seems to exert a radioprotective effect. Of note, the progression to a more pronounced fibrosis in WT mice was associated with altered expression of this molecule on immune cells during the pneumonitic phase, and with early and late changes in the composition and phenotype of immune cells, both locally and systemically. Thus, endogenous presence or absence of this immunoregulatory molecule results in distinct responses within the lung tissue, determining the progression and the final outcome of radiation-induced side effects. Remarkably, complete absence of mature B and T cells led to an increased sensitivity to radiation-induced fibrosis. This model provided evidence for a direct involvement of the immune system in the pathogenesis of lung radiation-induced pneumopathy. Regulation of the immune system during lung responses to ionizing radiation might therefore represent a good target for future treatments

Il castellum di Poggio Civitella (Montalcino, Siena)

Forthcoming

Il sito di Monte Giovi nell’ager Faesulanus

Forthcoming

An electric and electromagnetic geophysical approach for subsurface investigation of anthropogenic mounds in an urban environment

Scientific interest in mounds as geomorphological features that currently represent topographic anomalies in flat urban landscapes mainly lies on the understanding of their origin, either purely natural or anthropogenic. In this second circumstance, another question is whether traces of lost buildings are preserved within the mound subsurface and can be mapped as remnants testifying past settlement. When these landforms have been modified in centuries for civilian use, structural stability is a further element of concern. To address these issues we applied a geophysical approach based on a very low frequency electromagnetic (VLF-EM) technique and two dimensional electrical resistivity tomography (2D-ERT) and integrated it with well-established surface survey methods within a diagnostic workflow of structural assessment. We demonstrate the practical benefits of this method in the English Cemetery of Florence, Italy, whose mixed nature and history of morphological changes are suggested by archival records. The combination of the two selected geophysical techniques allowed us to overcome the physical obstacles caused by tomb density and to prevent interference from the urban vehicular traffic on the geophysical signals. Eighty-two VLF-EM profiles and five 2D-ERTs were collected to maximise the spatial coverage of the subsurface prospection, while surface indicators of instability (e.g., tomb tilt, location, and direction of ground fractures and wall cracks) were mapped by standard metric survey. High resistive anomalies (> 300 and 400 Ωm) observed in VLF-EM tomographies are attributed to remnants of the ancient perimeter wall that are still buried along the southern side of the mound. While no apparent correlation is found between the causes of tomb and ground movements, the crack pattern map supplements the overall structural assessment. The main outcome is that the northern portion of the retaining wall is classed with the highest hazard rate. The impact of this cost-effective approach is to inform the design of maintenance and restoration measures based on improved geognostic knowledge. The geophysical and surface evidence informs decisions on where interventions are to be prioritised and whether costly invasive investigations are needed