Water Absorption Properties of Cement Pastes: Experimental and Modelling Inspections

An intermingled fractal units’ model is shown in order to simulate pore microstructures as pore fraction and pore size distribution. This model is aimed at predicting capillary water absorption coefficient and sorptivity values in cement pastes. The results obtained are in good agreement with the experimental ones. For validating this model, a comparison with other procedures has been shown. It is possible to establish that the newly proposed method matches better with the experimental results. That is probably due to the fact that pore size distribution has been considered as a whole. Moreover, even though the proposed model is based on fractal base units, it is able to simulate and predict different properties as well as nonfractal porous microstructure

Alteration processes of geomaterials used on the pentagonal tower of Serravalle Castle (central-west Sardinia, Italy)

[EN] The pentagonal tower belong to medieval Serravalle castle area (81 m. above sea level), near the mouth of the Temo River. The castle is important medieval fortifications of Sardinia and was built in various stages. The oldest part was constructed by Marchesi Malaspina of Villafranca which arrived in Sardinia at the 12th century (1112-1121). The earliest fortification was the four corner towers about 10 m tall, linked by a thick wall. The pentagonal tower, located in the western corner of the boundary dates about 1330, probably was consisted of two storeys with wooden beams, now missing, and one stone one with a longitudinal arch. In the structure was used local volcanic rocks (i.e., pyroclastites) belonging to the Oligo-Miocenic volcanic cycle of Sardinia (32-11 Ma). According to De La Roche classification (1980), the pyroclastic rocks have a composition varying from dacite to rhyolite and show a porphyritic structure (I.P. from 10 to 20%) for phenocrystals of opaque (ilmenite, magnetite and/or titanomagnetite), plagioclase, ± biotite, and rare hornblend and quartz. Two main type of volcanics are present with different physical properties (porosity, density, etc.) and petro-volcanological characteristics (e.g., welding degree): cineritic pyroclastites, little welded, with average values of open porosity and bulk density of 36.3±2.6% and 1.50±0.07 g/cm3, respectively; lava-like ignimbrites, from medium to high welded, and average values of open porosity and bulk density of 22.5±5.9% and 1.99±0.15 g/cm3, respectively. As function of these different features and extremely heterogeneous, due to variable incidence of pumice, lithic- and crystal-clasts, the alteration is present mainly on volcanics with low welding and exposed to the sea-winds. Due to marine aerosol, salt efflorescences are present. These latter, together thermal and hydric cyclic dilatation, lead to various macroscopic physical alterations (decohesion, chromatic alteration, pitting, exfoliation, flaking, alveolation, differential degradation between the lithic-clasts and the vitreous matrix).Columbu, S.; Meloni, P. (2015). Alteration processes of geomaterials used on the pentagonal tower of Serravalle Castle (central-west Sardinia, Italy). En Defensive architecture of the mediterranean: XV to XVIII centuries. Vol. II. Editorial Universitat Politècnica de València. 373-380. https://doi.org/10.4995/FORTMED2015.2015.1757OCS37338

Integrated approach for post-fire reinforced concrete structures assessment

In order to assess decay in the mechanical characteristics of re-exposed Reinforced Concrete (RC), it is crucial to recon- struct the temperature time history and the evolution of strain and stress elds. In this paper, the state of the art of assessment methods is presented and applied to a real structure damaged by re. It is a prestressed RC industrial warehouse located in the outskirts of the city of Cagliari (Italy). The collected data of several assessment methods are presented in order to produce the owchart of an integrated approach for post- re investi- gation. Among the various techniques, the authors highlight a thorough laser scanner geometric survey and destructive and non-destructive testing. In addition, the temperature distribu- tion and its time history has been reconstructed by means of optical and Scanning Electron Microscopy, X-ray diffractom- etry, Thermogravimetric Differential Thermo-Analysis and calibrated Colorimetry. Actually, refurbishment is needed, but the structure withstood the re very well. Central columns displayed the most impor- tant damage, and several beams presented important de ec- tions having lost the prestressing actions of the tendons

Workability and chemical-physical degradation of limestone frequently used in historical Mediterranean architecture

Sedimentary rocks are among the most used in historical buildings, as they are more readily available in the area and because they are also more easily extractable, in virtue in general of lower mechanical resistance. among these the most used are limestones and sandstones. The former are represented by a remarkable variety of lithologies, with highly variable characteristics, passing from the almost pure, massive and not very porous limestones, to those with a variable arenaceous-clayey component which instead are characterized by a low compactness and consequent high porosity (up to 35%). In this study the calcarenites present in two geographic sectors of Sardinia are dealt with, by comparing them with similar showers present in other territorial contexts of the Mediterranean. The mineralogical-petrographic analyzes by optical microscope and XRD analysis of the "Pietra Cantone" limestone of Cagliari (south Sardinia) show, besides calcite, the presence of phyllosilicates and various other accessory minerals. SEM analyses show a very weak physical-mechanical microstructure

Pyroclastic Stones as Building Materials in Medieval Romanesque Architecture of Sardinia (Italy): Chemical-Physical Features of Rocks and Associated Alterations

The paper discusses the chemical-physical-petrographic features and decay processes of San Nicola Church (11th−14th century) building materials, one of the most representative Medieval Churches in Sardinia, stylistically attributable to the Romanesque architecture. The monument was built up into two stages and shows a characteristic size uniformity of the ashlars. The masonry is mainly made up of rhyodacitic pyroclastites belonging to the Sardinian Eocene-Miocene mag- matic phase (38–15 My). These volcanic rocks were widely used in Medieval architecture for the excellent workability, but its minero-petrographic features greatly favor the decay, due to the action of chemical-physical alteration processes. Although the alteration degree and macroscopic forms of decay vary from zone to zone in the monument, according to the different compositional features of the volcanic stones, weathering and exposure condition, the pyroclastic rocks are generally affected by greater alteration than other igneous lithotypes, due to their petrographic- volcanological characteristics (e.g., low-medium welding grade, medium-high porosity). The results concerning mineralogical and petrographic features, respectively, carried out by the application of X-Ray Powder Diffraction (XRPD), Optical Microscope (OM), and Scanning Electron Microscope (SEM) techniques, both on fresh building rocks and associated alterations, are here presented and discussed. Furthermore, the relationships between fresh pyroclastites and altera- tion processes affecting these rocks will be discussed

ALOHA: A Unified Platform-Aware Evaluation Method for CNNs Execution on Heterogeneous Systems at the Edge

CNN design and deployment on embedded edge-processing systems is an error-prone and effort-hungry process, that poses the need for accurate and effective automated assisting tools. In such tools, pre-evaluating the platform-aware CNN metrics such as latency, energy cost, and throughput is a key requirement for successfully reaching the implementation goals imposed by use-case constraints. Especially when more complex parallel and heterogeneous computing platforms are considered, currently utilized estimation methods are inaccurate or require a lot of characterization experiments and efforts. In this paper, we propose an alternative method, designed to be flexible, easy to use, and accurate at the same time. Considering a modular platform and execution model that adequately describes the details of the platform and the scheduling of different CNN operators on different platform processing elements, our method captures precisely operations and data transfers and their deployment on computing and communication resources, significantly improving the evaluation accuracy. We have tested our method on more than 2000 CNN layers, targeting an FPGA-based accelerator and a GPU platform as reference example architectures. Results have shown that our evaluation method increases the estimation precision by up to 5× for execution time, and by 2\times for energy, compared to other widely used analytical methods. Moreover, we assessed the impact of the improved platform-awareness on a set of neural architecture search experiments, targeting both hardware platforms, and enforcing 2 sets of latency constraints, performing 5 trials on each search space, for a total number of 20 experiments. The predictability is improved by 4\times , reaching, with respect to alternatives, selection results clearly more similar to those obtained with on-hardware measurements

Validation of the Treadmill Six-Minute Walk Test in People Following Cardiac Surgery

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Imbalance between nitric oxide generation and oxidative stress in patients with peripheral arterial disease: Effect of an antioxidant treatment

BackgroundNitric oxide (NO), a potent vasodilator produced by endothelial cells, is reduced in patients with peripheral arterial disease (PAD), but the mechanism has not been fully elucidated. Because NO is rapidly inactivated by superoxide anion, we speculated that enhanced oxidative stress could lower NO generation. The aim of our study was to investigate if an imbalance between oxidative stress and NO does exist in patients with PAD and if an increase of NO formation could be achieved by an antioxidant treatment.MethodsIn a first study, serum levels of nitrite and nitrate (NOx), markers of NO generation, and 8-hydroxy-2-deoxyguanosine (8-OHdG), a marker of oxidative stress and maximal walking distance (MWD), were measured in 40 PAD patients and 40 controls. In a second study, 10 PAD patients were randomly allocated in a crossover design to intravenous propionyl-L-carnitine (6 g/day) or placebo for 7 days, with a washout of 30 days between the two phases of the trial. Serum levels of NOx and 8-OHdG were measured before and after the study.ResultsCompared with controls, serum levels of 8-OHdG (mean ± SD) were significantly increased in PAD patients (4.4 ± 3.1 ng/mL vs 2.4 ± 1.2 ng/mL; P < .001), and serum levels of NOx were significantly decreased (11.6 ± 6 μM vs 17 ± 6.1 μM; P < .001). Levels of 8-OHdG and NOx were inversely correlated (r = −0.879; P < .001). Serum levels 8-OHdG were inversely correlated with MWD (r = −0.48, P = .002). The interventional trial showed no changes in the patients given placebo. Patients treated with propionyl-L-carnitine showed a significant increase of MWD from 101 ± 31 meters to 129 ± 35 meters (P = .007) and in NOx from 14.5 ± 4.5 μM to 17.1 ± 3.8 μM (P = .007). A significant decrease of 8-OHdG from 3.6 ± 1.1 ng/mL to 2.6 ± 1 ng/mL was also found (P = .005.)ConclusionsThis study suggests that in PAD patients, the reduction of NO generation could be dependent upon enhanced oxidative stress

Comparison of Quality of Internet Pages on Human Papillomavirus Immunization in Italian and in English

Purpose: Information available on the Internet about immunizations may influence parents' perception about human papillomavirus (HPV) immunization and their attitude toward vaccinating their daughters. We hypothesized that the quality of information on HPV available on the Internet may vary with language and with the level of knowledge of parents. To this end we compared the quality of a sample of Web pages in Italian with a sample of Web pages in English. Methods: Five reviewers assessed the quality of Web pages retrieved with popular search engines using criteria adapted from the Good Information Practice Essential Criteria for Vaccine Safety Web Sites recommended by the World Health Organization. Quality of Web pages was assessed in the domains of accessibility, credibility, content, and design. Scores in these domains were compared through nonparametric statistical tests. Results: We retrieved and reviewed 74 Web sites in Italian and 117 in English. Most retrieved Web pages (33.5%) were from private agencies. Median scores were higher in Web pages in English compared with those in Italian in the domain of accessibility (p < .01), credibility (p < .01), and content (p < .01). The highest credibility and content scores were those of Web pages from governmental agencies or universities. Accessibility scores were positively associated with content scores (p < .01) and with credibility scores (p < .01). A total of 16.2% of Web pages in Italian opposed HPV immunization compared with 6.0% of those in English (p < .05). Conclusions: Quality of information and number of Web pages opposing HPV immunization may vary with the Web site language. High-quality Web pages on HPV, especially from public health agencies and universities, should be easily accessible and retrievable with common Web search engines. (C) 2010 Society for Adolescent Medicine. All rights reserved