9 research outputs found
Methodological aspects in the experimental measurement of the interface friction between geosynthetics.
No full textAbstractThe evaluation of the interface friction at the contact between geosynthetics is a very important feature in a safe design of landfills and similar earth structures. Coupling different geosynthetics to fulfil multiple functions may be a critical point, due to the low frictional properties of such products. As a consequence, the assessment of the degree of safety of earth structures including geosynthetics requires a characterization of the interface strength and of its evolution with displacements. Some results obtained at the University of Padua will be presented with reference to experimental measurements of the interface friction between geosynthetics, in different conditions, to highlight the complexity of the friction phenomena and their dependence on experimental conditions
Experimental characterisation and modelling of capillary active material for internal insulating system
No full textLAUREA MAGISTRALELo scopo di questa tesi è l’approfondimento della caratterizzazione delle proprietà fisiche dei
materiali capillari attivi utilizzati nei sistemi di isolamento interno. Una delle proprietà
fondamentali è la diffusività di acqua liquida Dw, che è ricavata tramite un nuovo approccio
basato su un dispositivo a piastra calda (Guarded Hot Plate Apparatus), il quale genera una
differenza di contenuto di umidità tra la superficie superiore e inferiore del provino per mezzo
di un gradiente di temperatura. Determinando un’approssimata distribuzione del contenuto di
umidità, è possibile calcolare la diffusività di acqua liquida quando sono raggiunte condizioni di
stato stazionario. L’aspetto innovativo risiede nella semplicità del metodo e nella possibilità di
conoscere l’influenza della temperatura sulla diffusività dell’acqua liquida. In aggiunta,
interpolando i dati ricavati, è proposta una nuova funzione semi-empirica di distribuzione della
diffusività di acqua liquida. La validità del metodo è verificata tramite una simulazione
numerica implementata in Comsol Multiphysics.
In seguito è presentato un caso di studio che descrive la reale risposta di una parete,
modellizzata tramite una simulazione dinamica implementata in Comsol Multiphysics, per
studiare il comportamento della parete rispetto al rischio di formazione di muffa, che può
presentarsi tra lo strato di isolante e la parete esterna. Per valutare il rischio di formazione di
muffa è impiegato il modello delle Isoplete, il quale permette di stabilire se una certa condizione
di umidità relativa e temperatura dietro lo strato di isolante è rischiosa o sicura. Infine è
proposto un nuovo metodo capace di predire in modo preliminare e conservativo il rischio di
formazione di muffa, senza l’utilizzo di una simulazione numerica e superando il limite
dell’esistente metodo di Glaser esistente, il quale non permette di studiare i materiali capillari
attivi. Questo limite è superato dal metodo proposto, che si basa sull’analisi del flusso di vapore
e di acqua liquida all’interno del materiale isolante. Il metodo è validato tramite una
simulazione dinamica implementata in Comsol Multiphysics.The aim of this thesis is to improve the characterisation of the physical properties of capillary
active materials employed in the internal insulation systems. One of the most important property
is the liquid water diffusivity Dw, which is evaluated by means of a new approach based on the
Guarded Hot Plate Apparatus, which, under a temperature gradient, generates a water content
difference between the upper and lower surfaces of the specimen. Determining an approximated
water content distribution, the calculation of the liquid water diffusivity is possible when steady
state conditions are reached. The innovative aspects are the simplicity of the method and the
possibility to know the temperature influence on the liquid water diffusivity. Then, by means of
the interpolation of the empirical data, a new semi-empirical distribution function of the liquid
water diffusivity is proposed. The validity of the method is verified by means of a numerical
simulation implemented in Comsol Multiphysics.
Moreover, a case study describing the real response of an existing wall is analysed by means of
a numerical model implemented in Comsol Multiphysics, in order to study the behaviour of the
wall with respect to the risk of mould formation, which occurs at the interface between the
insulating layer and the external wall. The Isopleth model is taken into account, which allows
establishing if the condition of relative humidity and temperature behind the insulation is risky
of safe. Finally, a new method able to predict the risk of mould formation in a preliminary and
conservative way is presented, without employing a numerical simulation and overtaking the
limit of the existing Glaser method, cannot describe the behaviour of capillary active. This limit
is overtaken by the method here proposed, which analyses the vapour flux and the water liquid
flux inside the material. The method presented is further validated by means of a numerical
simulation by Comsol Multiphysics
La piattaforma GIS del Dizionario geografico fisico storico della Toscana di Emanuele Repetti: dalla mappa al GIS - dal GIS alla mappa
No full textIl Dizionario Geografico Fisico Storico della Toscana di Emanuele Repetti raccoglie preziose informazioni acquisite e organizzate dall'autore nella prima metà del XIX secolo sui luoghi della regione e costituisce per questo un testo insostituibile e di larga consultazione nell'ambito degli studi storico-geografici. Il valore dell'opera come esauriente repertorio in grado di fornire un quadro dettagliato della distribuzione insediativa del passato così come utili dati per la storia del popolamento, ha fatto sì che essa divenisse naturale risorsa documentaria da cui partire per uno studio del territorio. Nella prima parte del contributo verranno presentate le modalità di digitalizzazione dall'opera attraverso la realizzazione di una banca dati georiferita dei siti in essa registrati e della relativa piattaforma GIS. Nella seconda parte saranno illustrati alcuni aspetti del progetto attualmente in corso, finalizzati all'indagine dei paesaggi storici e relativi in particolare ad elaborazioni cartografiche realizzate sulla base della digitalizzazione dal Dizionario. Nell'ultima parte si accenna alla proposta di una possibile soluzione identificata per correlare differenti banche dati spaziali attraverso la costruzione di un indicatore spaziale sul quale procedere all’interfacciamento di più piattaforme GIS.Emanuele Repetti's Geographical Phisical and Historical Dictionary of Tuscany collects precious information recorded and organized by the author during the first half of the XIX century of places and towns of the region. These volumes represent a unique source for geographers and historian interested in this geographical area. The value of the text as an exhaustive inventory able to provide a detailed picture of past settlement distributions and also as useful source of population data has transformed it a starting point for every research in this region. In the first part of this paper will summarize the procedures adopted for the digitalization of Repetti's Dictionary. In particular we will discuss the construction of the GIS platform and the related geo-database. In the second part we will present some ongoing research applications. More precisely we will illustrate the application in the historical landscape studies and GIS applications for a reconstruction of demographic trends. In the last part we will discuss on how the use of a spatial index instead of a relational architecture represents a better option for the interface and linkage of GIS project developed by unfamiliar research groups
Hydrogen blending effect on fiscal and metrological instrumentation: A review
No full textA green hydrogen (H2) economy requires a sustainable, efficient, safe, and widespread infrastructure for transporting and distributing H2 from production to consumption sites. Transporting a hydrogen/natural gas (H2NG) mixture, including pure H2, through the existing European natural gas (NG) infrastructure is considered a cost-effective solution, particularly in the transitional phase. Several reasons justify the H2NG blending option. The NG infrastructure can be efficiently repurposed to transport H2, by blending H2 with NG, to operate as H2 daily storage, matching production and demand and to enable large-scale seasonal H2 storage. Although many benefits exist, the potential of existing NG grids for transporting and distributing green H2 may face limitations due to technical, economic, or normative concerns. This paper focuses on the state of the art of the European NG transmission and distribution metrology normative framework and identifies the gaps to be filled in case of H2NG flowing into the existing grids. The paper was revised to provide a comprehensive analysis of the practical implications resulting from the H2NG blend option
Who Controls the Content of Supreme Court Opinions?
No full textConventional arguments identify either the median justice or the opinion author as the most influential justices in shaping the content of Supreme Court opinions. We develop a model of judicial decision making that suggests that opinions are likely to reflect the views of the median justice in the majority coalition. This result derives from two features of judicial decision making that have received little attention in previous models. The first is that in deciding a case, justices must resolve a concrete dispute, and that they may have preferences over which party wins the specific case confronting them. The second is that justices who are dissatisfied with an opinion are free to write concurrences (and dissents). We demonstrate that both features undermine the bargaining power of the Court’s median and shift influence towards the coalition median. An empirical analysis of concurrence behavior provides significant support for the model.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/116097/1/ajps12.pd
Micro‐RNA‐21 (biomarker) and global longitudinal strain (functional marker) in detection of myocardial fibrotic burden in severe aortic valve stenosis: a pilot study
No full textAims: Myocardial fibrosis (MF) is a deleterious consequence of aortic valve stenosis (AVS). Global longitudinal strain (GLS) is a novel left ventricular (LV) functional parameter potentially useful to non-invasively estimate MF. MicroRNAs (miRNAs) are non-coding small ribonucleic acids (RNA) modulating genes function, mainly through RNA degradation. miRNA-21 is a biomarker associated with MF in pressure overload. The aim of the present study was to find an integrated algorithm for detection of MF using a combined approach with both bio- and functional markers. Methods: Thirty-six patients (75.2±8 y.o.; 63% Female) with severe AVS and preserved LV ejection fraction (EF), candidate to surgical aortic valve replacement (sAVR) were enrolled. Clinical, bio-humoral evaluation (including plasmatic miRNA-21 collected using specific tubes, PAXgene, for stabilization of peripheral RNA) and a complete echocardiographic study, including GLS and septal strain, were performed before sAVR. Twenty-eight of those patients underwent sAVR and, in 23 of them, an inter-ventricular septum biopsy was performed. Tissues were fixed in formalin and embedded in paraffin. Sections were stained with Hematoxylin and Eosin for histological evaluation and with histochemical Masson trichrome for collagen fibers. The different components were calculated and expressed as micrometers2. To evaluate tissue miRNA components, sections2-μm thick were cut using a microtome blade for each slide. Regression analysis was performed to test association between dependent variable and various predictors included in the model. Results: Despite a preserved EF (66±11%), patients presented altered myocardial deformation parameters (GLS -14,02±3.8%; septal longitudinal strain, SSL -9.63±2.9%; septal longitudinal strain rate, SL-Sr -0.58±0.17 1/s; Septal Longitudinal early-diastolic strain rate, SL-SrE 0.62±0.32 1/s). The extent of MF showed an inverse association with both GLS and septal longitudinal deformation indices (GLS: R2=0.30; p=0.02; SSL: R2=0.36; p=0.01; SL-Sr: R2=0.39; p<0.001; SL-SrE: R2=0.35; p=0.001). miRNA-21 was mainly expressed in fibrous tissue (p<0.0001). A significant association between MF and plasmatic miRNA-21, alone and weighted for measures of structural (LVMi R2=0.50; p=0.0005) and functional (SSL R2=0.35; p=0.006) remodeling, was found. Conclusions: In AVS, MF is associated with alterations of regional and global strain. Plasmatic miRNA-21 is directly related to MF and associated with LV structural and functional impairment. © 2016 The Author(s)
The CHAIN-REDS Semantic Search Engine
No full texte-Infrastructures, and in particular Data Repositories and Open Access Data Infrastructures, are essential platforms for e-Science and e-Research and are being built since several years both in Europe and the rest of the world to support diverse multi/inter-disciplinary Virtual Research Communities. So far, however, it is difficult for scientists to correlate papers to datasets used to produce them and to discover data and documents in an easy way. In this paper, the CHAINREDS project’s Knowledge Base and its Semantic Search Engine are presented, which attempt to address those drawbacks and contribute to the reproducibility of science
Austin also must be remembered. The Augustinian legacy in Milton's work
No full textWhen I started working on this project, with a limited knowledge of Augustine, but determined to spot his presence in Miltonâs poetry, I was little aware of the intricacy of the relationship between the two authors. At this stage of my research, I do subscribe to Savoyeâs opinion, that this relationship is pervasive. However, one could safely add, it is as pervasive as it is hidden, primarily because of changed cultural paradigms, so that Miltonâs references are no longer familiar to the reader.
As I have pointed out in my presentation of the state of the art, these articulations are hardly made explicit in Miltonâs Oeuvre and also in critical literature they are hardly brought to the surface. My objective has been to make them a little more visible.
I have started my own process of discovery from the works where Milton more openly (but not completely) acknowledges his Augustinian sources, although arguably mediated. As concerns Samson Agonistes, I have presented a reading through Augustinian lenses. I am by no means claiming that mine is the best of all possible readings, but through those lenses I have been able to see a coherence, in Miltonâs dramatic poem, that is not generally recognized.
On the other hand, I thoroughly agree that âone cannot simply take any English poet and turn the post-structuralist critical machine loose on him or her in good faithâ. In particular, I am aware that I have read Miltonâs works against the current critical grain which, with a powerful turn impressed by Empsonâs Miltonâs God, is continually surfacing Miltonâs idiosyncrasies in order to cancel the received picture of a Christian author. Rather, I agree with Cirillo that Miltonâs perspective is that of âa professed Christian poet whose Christian consciousness, no matter how heterodox, colored virtually everything he wrote.â.We may ask, echoing Febvre on Rabelais, âMais de quel christianisme? In accordance with very traditional, even traditionalist Milton Criticism, I think it can safely be stated that Milton is a post-Reformation religious author, and one whose endeavour to âjustify the ways of God to menâ had to come to terms with the difficult task to find signs of providential history in the aftermath of a civil war and in the adverse context of the Restoration. His last published poems deal with this problem in different terms. As readers, we can come to different conclusions as to the texts. Behind them there is the man, âest abyssus humanae conscientiae,â in front of which, after Augustine, I can only say: "nescio"
The use of mobile phones and the risk of brain tumors among children and adolescents
No full textMobile phones experienced a steep rise in popularity among children and adolescents during the last decade. The increase in popularity has been reflected in both increased ownership and increased usage of mobile phones. Most children start to use mobile phones when they are around 9–10 years old, but usage before school age is not uncommon. The increase in mobile phone use has raised concerns about possible adverse health effects. Brain tumors have been a main concern because the brain absorbs most of the radio frequency energy emitted by mobile phones during calls. In addition, it has been hypothesized that children may be more vulnerable to radio frequency electromagnetic fields (RF-EMFs) because their nervous system is developing, their brain tissue is more conductive than that of adults, and RF-EMFs penetrate in to regions that are deeper in their brains. Radio frequency radiation emitted by mobile phones has insufficient energy to directly damage the DNA and the only known effect of RF-EMFs is heating of the tissue. Studies about mobile phone use and brain tumor risk among adults have shown no increased risk for regular users but have been inconclusive regarding long-term (≥10 years) and heavy mobile phone use. The largest case-control study so far, INTERPHONE, found an increased risk for glioma among heavy users (≥1640 lifetime calls). Another study from a Swedish research group reported a five-fold increased risk for astrocytoma for adults who first used mobile phones before the age of 20. No study has addressed the association between mobile phone use and brain tumor risk among children and adolescents so far. The goal of this thesis was to assess whether there is a relationship between mobile phone use and brain tumor risk among children and adolescents or not. In 2006, we set up CEFALO, an international case-control study about the relationship between mobile phone use and brain tumor risk in children and adolescents aged 7–19 years. CEFALO was performed in Denmark, Sweden, Norway, and Switzerland. The study period ranged from 2004 through 2008. Children and adolescents of age 7–19 years who were diagnosed during the study period with a primary brain tumor were eligible. For each case patient, we selected two healthy controls matched by age, sex and geographical region of residence using population registries. Exposure data was collected by face to face interviews with the study participants accompanied by at least one parent. Risk estimates for brain tumors were calculated for various exposure surrogates. We also examined the gender and age-adjusted brain tumor incidence rates among Swedish children and adolescents aged 5–19 years from 1990 to 2008 including hypothetical incidence rate trends based on the risk estimates found in our analyses. Lastly, we compared the self-reported amount of mobile phone use with objectively recorded data by network operators. Regular users of mobile phones were not statistically significantly more likely to have been diagnosed with brain tumors compared with non-regular users (OR=1.36, 95%-CI: 0.92 to 2.02). No clear exposure-response relationship was observed for any exposure surrogate. Moreover, no exposure-response relationship was seen in terms of localization of the tumor. For the study participants for whom operator-recorded data were available, we found a statistically significantly increased risk among users with more than 2.8 years since the start of the first subscription (OR=2.15). The odds ratio for brain tumor risk among ipsilateral regular users of mobile phones was not higher than the odds ratio of contralateral regular users. The risk estimate of 2.15 after 3 years of regular mobile phone use is incompatible with the stable (or even downward) incidence trends observed among Swedish children and adolescents aged 5–19 years from 1990 to 2008. This indicates that short-term use of mobile phones does not cause brain tumors in children and adolescents. In the validation study, cases overestimated their cumulative number of calls by 9% on average and controls by 34%. Cases also overestimated their cumulative duration of calls by 52% on average and controls by 163%. We found little evidence for differential recall errors. CEFALO is the first study to investigate the relationship between mobile phone use and brain tumor risk in children and adolescents. We found no consistent evidence for a causal association between short-term mobile phone use and brain tumor risk among children and adolescents. The lack of an exposure-response relationship either in terms of the amount of mobile phone use or by localization of the brain tumor argues against a causal relationship. These findings are corroborated by the fact that brain tumor incidence rates among children and adolescents have not increased in many countries in recent times. We cannot, however, exclude the possibility of a small increase in brain tumor risk due to mobile phone use. As we found that self-reported mobile phone use is affected with large random and some systematic recall errors, we emphasize the importance of future studies with objective exposure assessment or the use of prospectively collected exposure data. We also recommend the monitoring of time trends in brain tumor incidence rates as increased risks should be reflected in future brain tumor incidence rate trends
