A multiscale Darcy-Brinkman model for fluid flow in fractured porous media

The aim of this work is to present a reduced mathematical model for describing fluid flow in porous media featuring open channels or fractures. The Darcy's law is assumed in the porous domain while the Stokes-Brinkman equations are considered in the fractures. We address the case of fractures whose thickness is very small compared to the characteristic diameter of the computational domain, and describe the fracture as if it were an interface between porous regions. We derive the corresponding interface model governing the fluid flow in the fracture and in the porous media, and establish the well-posedness of the coupled problem. Further, we introduce a finite element scheme for the approximation of the coupled problem, and discuss solution strategies. We conclude by showing the numerical results related to several test cases and compare the accuracy of the reduced model compared with the non-reduced on

The carbon footprint of the historic centre of the Municipality of Trevignano Romano - Lazio Region, Italy

Operations to quantify the CO2eq emissions of a given territory encounter critical issues that make the matter more complex because they are rooted in political/economic/social options carried out over time and in other locations; options that “come from elsewhere and far in time” and therefore make partial the technical solutions that are proposed today. Each intervention must therefore be “contextualized in space and time” otherwise the technical initiative in progress, not well understood, can create the misunderstanding of being proposed again, in other territorial contexts with deep and different connotations, with consequent results that are only partially positive. Moreover, each intervention, for an obvious economy of scale, must be correlated at the same time with similar ones and, in any case, all of them must be placed coherently within an economy that today goes towards industry 4.0. through digitalization. This case study precisely because it is placed “today” and “within” a specific context possesses such specificities that it allows (even foreign entrepreneurs, as well as national) to operate adequately. Following the analysis of the most suitable tools for measuring environmental impacts – on the building and urban scale – the carbon footprint procedure has been defined, the working methodology, the technical operations carried out and the calculation methods for quantifying the CO2eq emissions produced by the energy consumption of buildings and transport are illustrated through the indicators for the case study under examination, analysed at 360°. Finally, the proposal for the overall reduction of the calculated carbon footprint is illustrated and concludes with the results achieved and their possible further developments

A preliminary approach to study the behavior of human fingertip at contact via experimental test and numerical model

How human fingertip deforms during the interaction with the environment represents a fundamental action that shapes our perception of external world. In this work, we present the proof of concept of an experimental in vivo set up that enables to characterize the mechanical behavior of human fingertip, in terms of contact area, force and a preliminary estimation of pressure contour, while it is put in contact against a flat rigid surface. Experimental outcomes are then compared with the output of a 3D Finite Element Model (FEM) of the human fingerpad, built upon existing validated models. The good agreement between numerical and experimental data suggests the correctness of our procedure for measurement acquisitions and finger modeling. Furthermore, we will also discuss how our experimental data can be profitably used to estimate strain limiting deformation models for tactile rendering, while the here reported 3D FE model has also been profitably employed to investigate hypotheses on human tactile perception

Recurrence following anastomotic leakage after surgery for carcinoma of the distal esophagus and gastroesophageal junction. a systematic review

BACKGROUND: Esophageal cancer is the ninth most common cancer. The only potentially curative treatment is surgical resection, which unfortunately is still associated with major complications, the most important being anastomotic leakage, currently with an overall rate of up to 26% morbidity. The aim of this systematic review was to evaluate the relationship between anastomotic leakage and recurrence of disease. MATERIALS AND METHODS: A literature search was systematically performed. Seven out of 312 articles dated between 2009 and 2018 fulfilled the selection for a total of 5,433 patients. RESULTS: The frequency of anastomotic leakage ranged from 7.2 to 11.2%. Patients affected by anastomotic leakage had a recurrence rate of 9-56%. CONCLUSION: Closer follow-up or even more aggressive oncological therapy should be considered for patients affected by anastomotic leakage after surgery for carcinoma of the distal esophagus and gastroesophageal junction

Caught while Dissolving: Revealing the Interfacial Solvation of the Mg2+ Ions on the MgO Surface

Interfaces between water and materials are ubiquitous and are crucial in materials sciences and in biology, where investigating the interaction of water with the surface under ambient conditions is key to shedding light on the main processes occurring at the interface. Magnesium oxide is a popular model system to study the metal oxide-water interface, where, for sufficient water loadings, theoretical models have suggested that reconstructed surfaces involving hydrated Mg2+ metal ions may be energetically favored. In this work, by combining experimental and theoretical surface-selective ambient pressure X-ray absorption spectroscopy with multivariate curve resolution and molecular dynamics, we evidence in real time the occurrence of Mg2+ solvation at the interphase between MgO and solvating media such as water and methanol (MeOH). Further, we show that the Mg2+ surface ions undergo a reversible solvation process, we prove the dissolution/redeposition of the Mg2+ ions belonging to the MgO surface, and we demonstrate the formation of octahedral [Mg(H2O)6]2+ and [Mg(MeOH)6]2+ intermediate solvated species. The unique surface, electronic, and structural sensitivity of the developed technique may be beneficial to access often elusive properties of low-Z metal ion intermediates involved in interfacial processes of chemical and biological interest

Energy requalification and waste production: new urban metabolism processes. A case study in Trevignano Romano

A distorted urban development, built in the absence of specific regulations, obliges today to carry out energy requalification interventions. In an economic/regulatory context that requires the transition, from an artisan logic to a para-industrial one, towards industry 4.0 with greater economies of scale, acting not on individual buildings but on urban sectors. It also means putting the statutory and functional profile up to standard to meet the needs of the society. We refer to new processes of urban metabolism which, in the circular economy, in construction also means the reuse and recycling of its own waste. This contribution, regarding some researches carried out at the Interdepartmental Center Territory, Building, Restoration, Environment CITERA of Sapienza University of Rome, evaluates the incoming and outgoing flows (matter / energy) in urban centers, to point out best system efficiencies. Objective in a nutshell: the balance between the benefits obtained from the interventions and the impacts caused by the waste related. The paper illustrates: working methodology, technical operations carried out, calculation methods through indicators analyzed at 360°. Finally, the proposal for the overall reduction of energy consumption, C&D waste and CO2eq emissions and ends with the results achieved and possible further developments. The results confirm that if properly managed, the waste inevitably produced as a result of the interventions can turn from problem to resource

A Finite element model of tactile flow for softness perception

Touch is an extremely dynamic sense. To take into account this aspect, it has been hypothesized that there are mechanisms in the brain that specialize in processing dynamic tactile stimuli, in a way not too dissimilar from what happens for optical flow in dynamic vision. The concept of tactile flow, related to the rate of expansion of isostrain volumes in the human fingerpad, was used to explain some perceptual illusions as well as mechanisms of human softness perception. In this paper we describe a computational model of tactile flow, and apply it to a finite element model of interaction between deformable bodies. The shape and material properties of the bodies are modeled from those of a human fingertip interacting with specimens with different softness properties. Results show that the rate of expansion of isostrain volumes can be used to discriminate different materials in terms of their softness characteristics

Avelumab in gastric cancer

Gastric cancer (GC) is the fifth most common malignancy and the third cause of cancer-related deaths worldwide. Currently, surgery and chemotherapy remain the main therapeutic options and the prognosis of the disease is still poor in the metastatic setting. Avelumab is a human IgG1 antibody directed against PD-L1 approved for Merkel cell carcinoma and urothelial carcinoma that could be useful also for the treatment of GC. This review describes the chemical structure, the pharmacologic properties and the current knowledge of the efficacy of avelumab in the treatment of GC from the data available on the first and later phase clinical trials. The ongoing studies testing this drug either alone or in combination with other drugs are also described