Experimental investigations and analysis of piles as heat exchangers in pyroclastic soils

Sustainability and the greenhouse gases containment are the main purpose of the world policies to combat climate change. These are certainly in contrast with the world's growing demand for energy that is still too heavily based on fossil fuels, which are the main causes of gas emissions. The European Energy policies for more than 20 years have been based on the reduction of the carbon dioxide emissions using renewable energy sources and the reducing the final energy consumption. Shallow Geothermal Energy (SGE) is a rapidly growing technology all over Europe as a support for the Renewable Energy policies and European Directives because of its low greenhouse gas emissions into the atmosphere. It is considered a renewable source on the timescales of technological/societal systems because do not require the geological times of fossil fuel reserves such as coal, oil, and gas. Low enthalpy geothermal energy is used for heating and/or cooling building by exploiting the ground heat by ground heat exchangers connected to a geothermal source heat pump (GSHP). Energy piles represents a rather innovative technology that couples the role of the structural foundation with the role of the heat exchangers for GSHP plants to satisfy the building heating and cooling needs. Compared to the traditional pile foundations, these structures are loaded both by mechanical and thermal loads, where for thermal loads is commonly intended the application of a thermal distortion. During the last years, thermal and thermomechanical behavior of energy piles has been investigated by different approaches. In this PhD thesis the main aim was to investigate on the thermomechanical behavior of energy piles contextualized in Neapolitan context both by a geotechnical and energy point of view. First of all, a general overview about the social and energy European context and about the geothermal energy, an introduction to energy piles, by both a mechanical and an energetical point of view, was reported. The research was carried out following three different approaches: numerical modelling, small-scale tests, and field scale tests. As regard the numerical modelling, two types of analyses were carried out. In the former case by an axisymmetric FEM model, the impact of different surface thermal boundary conditions on the thermomechanical behavior of a single end bearing energy pile embedded in pyroclastic multilayer soil is investigated. The latter case is about the study of the interaction factors for a couple of energy piles where only one is thermally loaded while the other is embedded as a passive element in the deformation field generated by the loaded pile. The results were obtained for different pile spacings and for different subsoil and are presented in the chapter 4. Chapter 5 is dedicated to the small-scale test carried out on an aluminum energy prototype pile embedded in Neapolitan pyroclastic dry sand. Both thermal and thermomechanical tests were carried out considering a cyclical application of the thermal loads both in heating and in cooling mode and also considering the impact of different mechanical loads. The thermal loads provided to pile was obtained from a dynamic energy simulation of a building in the city of Naples. The results showed different axial forces distribution depending on the kind and magnitude of thermal and mechanical load applied on pile. Moreover, it was observed irreversible pile displacements during the application of cyclic thermal loads. Finally, in the chapter 6 a field test was carried out in the province of Naples on a bored concrete energy pile 12 m in length and 0,60 m in diameter embedded in pyroclastic soil and equipped with a spiral heat exchanger configuration. Three heating thermal tests with different time duration were carried out. From the tests was observed that the null point of the pile was located at the same depth for all the tests. Anyway, the magnitude of the axial forces depended on the duration of the test and the magnitude of the inlet heat carrier fluid. The pile heating did not affect the surrounding soil temperatures during the tests and a high flow rate of heat power exchanged between the pile and soil was measured. The measured pile displacements ranged between the 75% and 78% of the theoretical free displacement. Moreover, a long-time monitoring of the pile and surrounding soil was carried out for about 7 months. The data collected allowed to study the site underground temperatures trend over the time and for different depth. It was also possible to find the mean value of the subsoil thermal diffusivity and consequently predict a yearly temperature trend over the time and for different depth for the site

High thermal conductivity concrete for energy piles

Research is increasingly focusing on thermal properties of concrete with the aim of reducing the heat exchange between buildings and environment. On the other hand, concretes with high thermal conductivity could have interesting applications in the field of thermo-active ground structures as Geothermal Energy Piles (GEPs). This kind of foundations represent an environmentally friendly technology that allows exploiting the heat of the shallow earth surface to supply renewable energy for the air conditioning of buildings. GEPs are needed for structural and geotechnical reasons and allow recovering the installation costs connected to vertical boreholes. Concrete drilled or driven piles are equipped with a Primary Circuit (PC) of high-density polyethylene plastic pipes attached to the reinforcement cages. Thermal energy is extracted from or injected into the ground thought a carrier fluid that flows into the pipes of the PC. To improve the heat exchange between the pile and soil the thermal properties of the concrete should be considered as design parameters. Concrete thermal conductivity, contrary to what happens for the buildings, should be increased to optimise the thermal performance of the GEPs. Different solutions that modify the mix design of concrete are proposed to the aim of increasing the thermal performance of GEPs

Cryptides Identified in Human Apolipoprotein B as New Weapons to Fight Antibiotic Resistance in Cystic Fibrosis Disease

Chronic respiratory infections are the main cause of morbidity and mortality in cystic fibrosis (CF) patients, and are characterized by the development of multidrug resistance (MDR) phenotype and biofilm formation, generally recalcitrant to treatment with conventional antibiotics. Hence, novel eective strategies are urgently needed. Antimicrobial peptides represent new promising therapeutic agents. Here, we analyze for the first time the ecacy of three versions of a cryptide identified in human apolipoprotein B (ApoB, residues 887-922) towards bacterial strains clinically isolated from CF patients. Antimicrobial and anti-biofilm properties of ApoB-derived cryptides have been analyzed by broth microdilution assays, crystal violet assays, confocal laser scanning microscopy and scanning electron microscopy. Cell proliferation assays have been performed to test cryptide eects on human host cells. ApoB-derived cryptides have been found to be endowed with significant antimicrobial and anti-biofilm properties towards Pseudomonas and Burkholderia strains clinically isolated from CF patients. Peptides have been also found to be able to act in combination with the antibiotic ciprofloxacin, and they are harmless when tested on human bronchial epithelial mesothelial cells. These findings open interesting perspectives to cryptide applicability in the treatment of chronic lung infections associated with CF disease

Loading of Polydimethylsiloxane with a Human ApoB-Derived Antimicrobial Peptide to Prevent Bacterial Infections

Background: medical device-induced infections affect millions of lives worldwide and innovative preventive strategies are urgently required. Antimicrobial peptides (AMPs) appear as ideal candidates to efficiently functionalize medical devices surfaces and prevent bacterial infections. In this scenario, here, we produced antimicrobial polydimethylsiloxane (PDMS) by loading this polymer with an antimicrobial peptide identified in human apolipoprotein B, r(P)ApoBLPro. Methods: once obtained loaded PDMS, its structure, anti-infective properties, ability to release the peptide, stability, and biocompatibility were evaluated by FTIR spectroscopy, water contact angle measurements, broth microdilution method, time-killing kinetic assays, quartz crystal microbalance analyses, MTT assays, and scanning electron microscopy analyses. Results: PDMS was loaded with r(P)ApoBLPro peptide which was found to be present not only in the bulk matrix of the polymer but also on its surface. ApoB-derived peptide was found to retain its antimicrobial properties once loaded into PDMS and the antimicrobial material was found to be stable upon storage at 4◦ C for a prolonged time interval. A gradual and significant release (70% of the total amount) of the peptide from PDMS was also demonstrated upon 400 min incubation and the antimicrobial material was found to be endowed with anti-adhesive properties and with the ability to prevent biofilm attachment. Furthermore, PDMS loaded with r(P)ApoBLPro peptide was found not to affect the viability of eukaryotic cells. Conclusions: an easy procedure to functionalize PDMS with r(P)ApoBLPro peptide has been here developed and the obtained functionalized material has been found to be stable, antimicrobial, and biocompatible

Evidence-based considerations exploring relations between sars-cov-2 pandemic and air pollution: Involvement of pm2.5-mediated up-regulation of the viral receptor ace-2

The COVID-19/SARS-CoV-2 pandemic struck health, social and economic systems worldwide, and represents an open challenge for scientists —coping with the high inter-individual variability of COVID-19, and for policy makers —coping with the responsibility to understand environmental factors affecting its severity across different geographical areas. Air pollution has been warned of as a modifiable factor contributing to differential SARS-CoV-2 spread but the biological mechanisms underlying the phenomenon are still unknown. Air quality and COVID-19 epidemiological data from 110 Italian provinces were studied by correlation analysis, to evaluate the association between particulate matter (PM)2.5 concentrations and incidence, mortality rate and case fatality risk of COVID-19 in the period 20 February–31 March 2020. Bioinformatic analysis of the DNA sequence encoding the SARS-CoV-2 cell receptor angiotensin-converting enzyme 2 (ACE-2) was performed to identify consensus motifs for transcription factors mediating cellular response to pollutant insult. Positive correlations between PM2.5 levels and the incidence (r = 0.67, p < 0.0001), the mortality rate (r = 0.65, p < 0.0001) and the case fatality rate (r = 0.7, p < 0.0001) of COVID-19 were found. The bioinformatic analysis of the ACE-2 gene identified nine putative consensus motifs for the aryl hydrocarbon receptor (AHR). Our results confirm the supposed link between air pollution and the rate and outcome of SARS-CoV-2 infection and support the hypothesis that pollution-induced over-expression of ACE-2 on human airways may favor SARS-CoV-2 infectivity

The Natural History of Peyronie's Disease

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OSMOSIS: Enabling Multi-Tenancy in Datacenter SmartNICs

Multi-tenancy is essential for unleashing SmartNIC's potential in datacenters. Our systematic analysis in this work shows that existing on-path SmartNICs have resource multiplexing limitations. For example, existing solutions lack multi-tenancy capabilities such as performance isolation and QoS provisioning for compute and IO resources. Compared to standard NIC data paths with a well-defined set of offloaded functions, unpredictable execution times of SmartNIC kernels make conventional approaches for multi-tenancy and QoS insufficient. We fill this gap with OSMOSIS, a SmartNICs resource manager co-design. OSMOSIS extends existing OS mechanisms to enable dynamic hardware resource multiplexing on top of the on-path packet processing data plane. We implement OSMOSIS within an open-source RISC-V-based 400Gbit/s SmartNIC. Our performance results demonstrate that OSMOSIS fully supports multi-tenancy and enables broader adoption of SmartNICs in datacenters with low overhead.Comment: 12 pages, 14 figures, 103 reference