Lattice Boltzmann Method for pore-scale multi-phase flow simulation in Underground Porous Media: a review

The study of fluid flow in porous media is relevant in various applications from chemical to environmental and geoenergy engineering. Understanding and properly simulating multi-phase flow phenomena at both micro and macro scales is fundamental in particular in the view of underground storage of fluids like methane, hydrogen, and CO2. This work aims at resuming the idea behind the Lattice Boltzmann Method (LBM) for modeling multi-phase flows through underground porous media, aiming at highlighting the advantages, and the possible approaches for single-phase and multi-phase flow. Moreover, an algorithmic analysis is given in single-phase and compared to more popular multi-phase Lattice Boltzmann models proposed and their main computing strategies. Direct numerical simulation (DNS) of flow in porous structures has become popular in recent years due to the novel high-performance computing architectures, which involve many cores or threads in calculation. This work concludes with an overview of the most common open-source codes available online to approach porous media flow simulation in this context and emphasize the most common for HPC applications

Wine industry’s attitude towards oenological yeasts : Italy as a case study

Yeast inoculation is a widespread practice in winemaking in order to control the must fermentation. However, the use of indigenous wine yeasts can enrich wine quality and differentiate wine styles. Yeast cream preparation (CRY), recently accepted by the International Organization of Vine and Wine, could allow an easier usage of autochthonous yeasts. This work aimed at investigating the actual Italian wine industry\u2019s attitude towards the available formulations of commercial wine yeasts with attention to CRY. Moreover, this study evaluated the perception of wineries toward indigenous yeasts in both winemaking and marketing viewpoints. Data show different levels of knowledge and use about the available yeast formulations. In general, there is not a predominantly positive or negative participants\u2019 opinion regarding the use of indigenous yeasts. Wineries using CRY (4% of the sample) mainly adopt them as a part of the production in order to compare the wines with the ones traditionally obtained with commercial yeasts. CRY is perceived by some interviewees as a potential tool to increase communication and product differentiation. This survey could have anticipated future trends in the use of yeast formulations, determined by the market demands for diversified, unique, and environmentally sustainable products, that can allow an accessible application of precision enology

Characterization of marble weathering through pore structure quantitative analysis

Y Stone weathering is strongly controlled by the intrinsic properties of the stone and by its use. Previous studies demonstrate that the response to natural or artificial ageing processes of the rocks seems to be strongly influenced by the pore structure of the stone. A better understanding of this phenomenon is provided by the study and characterization of porosity and of the pore structure at different degrees of alteration. The analysis of the evolution of the decay leads to the evaluation of the durability of marble in facades, and more generally in buildings, as well as for the protection and recovery of artistic and architectural heritage.In this paper, we apply a methodology for the geometrical characterization of the pore structure to quantify alteration induced by natural weathering on marble slabs. The approach is based on the application of a path-finding algorithm to 2D binary images representative of thin sections of marble at different degrees of alteration. Through the identification of the paths within the porous domain, the methodology allows the characterization of the pore structure in terms of pore radius distribution along the identified paths. Analysis of the results demonstrate a good agreement between the degree of alteration of the pore structure and the corresponding variation of the physical and mechanical properties of the rock samples under investigation

Heterologous Materials Are Really Better than Autologous in Tympanoplasty Mastoid Obliteration? A Systematic Review with Meta-Analysis

BACKGROUND: The aim is to analyze Literature concerning mastoid obliteration in adults with either autologous or heterologous grafts in the last 10 years. Data Source: Databases such as NIH PubMed, Bookshelf, NLM Catalog, Cochrane Library, and Embase were consulted. METHODS: Thirty-seven studies were selected (22 concerning autologous materials, 15 about heterologous ones). Only studies with more than 12 months of follow-up were considered. A statistical analysis with random-effects models was performed to allow the true effect sizes to differ from study to study. RESULTS: The present literature review and meta-analysis does not allow to establish the supremacy of one technique over the other, but underlines the advantages of each reconstructive choice and the importance of mastoid obliteration in cholesteatoma surgery. The total number of obliterated ears was 2882. Overall otorrhea rate was 5% (5.2% for heterologous grafts; 4.9% for autologous materials; P < .05). Recurrent and residual cholesteatoma rate was 4.5% (3.4% in heterologous materials; 5.2% in autologous grafts; P < .05). Recurrent cholesteatoma rate was 1.8% (1.6% when using heterologous grafts, 1.9% with autologous; P < .05). Residual cholesteatoma rate was 1.5% (1.6% with heterologous materials, 1.5% with autologous; P < .05). TM (tympanic membrane) retraction pockets rate was 5.3% (3.6% with heterologous materials; P >.05; 7% with autologous materials; P < .05). TM perforations rate was 2.9% (4.3% with heterologous materials, 2.5% with autologous; P < .05). Infection rate was 2.3% (2.3% with heterologous materials, 2.2% with autologous; P < .05). CONCLUSION: Heterologous materials are associated with significantly lower rates of recurrent and residual cholesteatoma and retraction pockets development, although they are associated with higher rates of otorrhea and TM perforation

Design, Fabrication, and Experimental Validation of Microfluidic Devices for the Investigation of Pore-Scale Phenomena in Underground Gas Storage Systems

The understanding of multiphase flow phenomena occurring in porous media at the pore scale is fundamental in a significant number of fields, from life science to geo and environmental engineering. However, because of the optical opacity and the geometrical complexity of natural porous media, detailed visual characterization is not possible or is limited and requires powerful and expensive imaging techniques. As a consequence, the understanding of micro-scale behavior is based on the interpretation of macro-scale parameters and indirect measurements. Microfluidic devices are transparent and synthetic tools that reproduce the porous network on a 2D plane, enabling the direct visualization of the fluid dynamics. Moreover, microfluidic patterns (also called micromodels) can be specifically designed according to research interests by tuning their geometrical features and surface properties. In this work we design, fabricate and test two different micromodels for the visualization and analysis of the gas-brine fluid flow, occurring during gas injection and withdrawal in underground storage systems. In particular, we compare two different designs: a regular grid and a real rock-like pattern reconstructed from a thin section of a sample of Hostun rock. We characterize the two media in terms of porosity, tortuosity and pore size distribution using the A* algorithm and CFD simulation. We fabricate PDMS-glass devices via soft lithography, and we perform preliminary air-water displacement tests at different capillary numbers to observe the impact of the design on the fluid dynamics. This preliminary work serves as a validation of design and fabrication procedures and opens the way to further investigations

Harmonic Pulse Testing for Well Monitoring: application to a fractured geothermal reservoir

Harmonic Pulse Testing (HPT) has been developed as a type of well testing applicable during ongoing field operations because a pulsed signal is superimposed on background pressure trend. Its purpose is to determine well and formation parameters such as wellbore storage, skin, permeability and boundaries within the investigated volume. Compared to conventional well testing, HPT requires more time to investigate the same reservoir volume. The advantage is that it does not require the interruption of well and reservoir injection/production before and/or during the test because it allows the extraction of an interpretable periodic signal from measured pressure potentially affected by interference. This makes it an ideal monitoring tool. Interpretation is streamlined through diagnostic plots mimicking conventional well test interpretation methods. To this end, analytical solutions in the frequency domain are available. The methodology was applied to monitor stimulation operations performed at an Enhanced Geothermal System (EGS) site in Pohang, Korea. The activities were divided into two steps: first a preliminary sequence of tests, injection/fall‐off and two HPTs, characterized by low injection rates and dedicated to estimate permeability prior to stimulation operations; then stimulation sequence characterized by higher injection rate. During the stimulation operations other HPTs were performed to monitor formation properties behavior. The interpretation of HPT data through the derivative approach implemented in the frequency domain provided reliable results in agreement with the injection test. Moreover, it provided an estimation of hydraulic properties without cessation of stimulation operations, thus confirming the effectiveness of HPT application for monitoring purposes

El perfil docente en la formación catequístico-teológico

A partir del inicio enla Universidad Católicade las carreras de Ciencias Sagrada y Teología y, después de varias promociones  surge la necesidad de revisar la estructura de cada una de ellas con el propósito de definir o redefinir el perfil del docente egresado.A tal fin se analizarán los programas, metodología, estructura y las competencias a desarrollar en sus espacios curriculares a lo largo de ambas carreras