Simulation of Turbulent Flows with and without Combustion with Emphasis on the Impact of Coherent Structures on the Turbulent Mixing

The analysis of turbulent mixing in complex turbulent flows is a challenging task. The effective mixing of entrained fluids to a molecular level is a vital part of the dynamics of turbulent flows, especially when combustion is involved. The work has shown the limitations of the steady-state simulations and acknowledged the need of applying high-fidelity unsteady methods for the calculation of flows with pronounced unsteadiness promoted by large-scale coherent structures or other sources

SDGs in corporate responsibility reporting: a longitudinal investigation of institutional determinants and financial performance

Companies play a central role in the achievement of Sustainable Development Goals (SDGs); as such, they face institutional pressures to increase their engagement with SDGs. However, given the complexity of SDGs, it is unclear whether these pressures lead firms to adopt engagement approaches that address a few goals or the whole set of 17, and if that choice has any subsequent effect on financial performance. To shed light on these issues, this research draws on the neo-institutional theory to investi- gate whether two institutional determinants—industry type and country of origin— affect SDG engagement and whether such engagement improves financial perfor- mance. Based on a content analysis and a regression analysis on high-reputation companies (the 100 most sustainable firms in the world) over the period 2017–2020, we find that the institutional pressures associated with industry type and country- of-origin positively impact any engagement approach to SDGs. However, we estab- lish that companies’ financial performance only generally improves when engaging with either the whole set of SDGs or a specific subset of the most frequently cited. This study provides important theoretical and practical contributions that illuminate firms’ institutional and financial rationales for adopting SDGs

Analysing Urban Dynamics in Historic Settlements Using a Geo-Spatial Infrastructure. The Venice’s Nissology project

This paper presents the ERC StG project Venice’s Nissology (VeNiss), a semantic geo-spatial web infrastructure for reconstructing over five-centuries of transformations of Venice’s lagoon islands, alongside their interwoven relationships in a geographically- and temporally-based digital environment. VeNiss constitutes the first analytical methodology for investigating, interpreting, and visualising, through computational media, the connective dynamics of centre-periphery relations in historic settlements, with specific reference to archipelagoes. Through a transdisciplinary approach, which combines history, architecture, art history, social studies, and advanced digital technologies the research infrastructure enables the intersection of historical data with georeferenced maps, 2D reconstructions, and 3D interoperable models to express the urban processes that shaped the lagoon city from the sixteenth century

Simulation of Turbulent Flows with and without Combustion with Emphasis on the Impact of Coherent Structures on the Turbulent Mixing

The analysis of turbulent mixing in complex turbulent flows is a challenging task. The effective mixing of entrained fluids to a molecular level is a vital part of the dynamics of turbulent flows, especially when combustion is involved. Turbulent mixing is a three-stage process of entrainment, stirring and diffusion, and the numerical simulation of turbulent mixing has to consider these three different phenomena. To achieve high-fidelity results, time dependent simulations are mandatory

Validation study for Large-Eddy Simulation of Forest Flow

The publication presents Large-Eddy Simulation (LES) of flow over a reduced-scale wind tunnel model of a forest canopy. The final aim of the study is to determine factors responsible for damage in forests by strong winds. The wind tunnel forest was represented by an open-porous foam material for the crown layer and wooden dowels for the trunk layer. The forest model was installed in the open test section of a Goettingen-type wind tunnel and Particle Image Velocimetry (PIV) measurements were made for the acquisition of the flow field data. The numerical simulations were performed with OpenFOAM®. The forest was modelled by an additional sink term in the momentum transport equations based on the leaf area density and a characteristic drag coefficient for the underlying tree specimen. Large-eddy simulations with different subgrid-scale (SGS) turbulence models were carried out and compared to wind tunnel data. The Smagorinsky SGS model outperformed the dynamic Lagrangian SGS model in the windward edge region (within a distance of approximately 2 tree heights from the leading edge) whereas the dynamic Lagrangian SGS model showed a better performance for regions farther downstream

Della eccellenza et dignita delle donne opera noua non piu stampata / Galeazzo Flauio Capella milanese

30, [2] c. ; 8º Frontespizio con cornice Cors Segn.: A-H⁴ Bianche le ultime due c

Photochemical box modelling of volcanic SO2 oxidation: isotopic constraints

The photochemical box model CiTTyCAT is used to analyse the absence of oxygen mass-independent anomalies (O-MIF) in volcanic sulfates produced in the troposphere. An aqueous sulfur oxidation module is implemented in the model and coupled to an oxygen isotopic scheme describing the transfer of O-MIF during the oxidation of SO2 by OH in the gas-phase, and by H2O2, O3 and O2 catalysed by TMI in the liquid phase. Multiple model simulations are performed in order to explore the relative importance of the various oxidation pathways for a range of plausible conditions in volcanic plumes. Note that the chemical conditions prevailing in dense volcanic plumes are radically different from those prevailing in the surrounding background air. The first salient finding is that, according to model calculations, OH is expected to carry a very significant O-MIF in sulfur-rich volcanic plumes and, hence, that the volcanic sulfate produced in the gas phase would have a very significant positive isotopic enrichment. The second finding is that, although H2O2 is a major oxidant of SO2 throughout the troposphere, it is very rapidly consumed in sulfur-rich volcanic plumes. As a result, H2O2 is found to be a minor oxidant for volcanic SO2. According to the simulations, oxidation of SO2 by O3 is negligible because volcanic aqueous phases are too acidic. The model predictions of minor or negligible sulfur oxidation by H2O2 and O3, two oxidants carrying large O-MIF, are consistent with the absence of O-MIF seen in most isotopic measurements of volcanic tropospheric sulfate. The third finding is that oxidation by O2∕TMI in volcanic plumes could be very substantial and, in some cases, dominant, notably because the rates of SO2 oxidation by OH, H2O2 and O3 are vastly reduced in a volcanic plume compared to the background air. Only cases where sulfur oxidation by O2∕TMI is very dominant can explain the isotopic composition of volcanic tropospheric sulfate

Impairment of small airways in COPD patients with frequent exacerbations and effects of treatment with tiotropium

Disease exacerbations are an important aspect of COPD, because they affect its course and are associated with higher lung function decline. On the other hand, data obtained by biopsies have demonstrated that the progression of COPD is related to an increasing impairment of small airways. We sought to evaluate the small airway impairment (FEF25–75) in two groups of COPD patients (each group had 37 subjects) in relation to the frequency of exacerbations and the effectiveness of treatment with tiotropium bromide on the small airway impairment. The mean number of exacerbations was 3.6/year and 1.38/year in frequent and in infrequent exacerbators, respectively (p < 0.001). The mean value of FEF25–75 at baseline was 624 mL and 865 mL in frequent and in infrequent exacerbators respectively (p = 0.002). The changes in respiratory parameters versus baseline showed increases in mean FEV1, FVC, and FEF25–75 in both groups but only the increase in FEF25–75 in frequent exacerbators was statistically significantly (p = 0.013). During the 3-month period of the study the mean number of exacerbations was 0.66 in frequent and 0.12 in infrequent exacerbators. These findings indicate that COPD patients with frequent exacerbations have a higher impairment of small airways. Treatment with tiotropium in COPD subjects with frequent exacerbations proved to be effective in improving small airway impairment