Efficiency of CFRP NSM strips and EBR laminates for flexural strengthening of RC beams

The efficiency of Fiber Reinforced Polymer (FRP) materials for strengthening existing Reinforced Concrete (RC) structures according to the Near Surface Mounted (NSM) technique can be greater than the External Bonded Reinforcement (EBR) technique since the tensile strength of the FRP materials is in general better exploited. Firstly, this paper deals with analyzing the effect of the loading pattern on RC beams strengthened with both types of strengthening technique; in particular, two loading patterns have been used for the experimental tests on simple supported beams: 1) a four points bending scheme, and 2) a scheme with distributed loads, in order to check the sensitivity of failure modes and ultimate loads to different distributions of bending moment and shear along the beam. Then, a comparison between the results of flexural tests on RC beams strengthened with both NSM and EBR techniques is dealt with

Zinc ions alter morphology and chitin deposition in an ericoid fungus

A sterile mycelium PS IV, an ascomycete capable of establishing ericoid mycorrhizas, was used to investigate how zinc ions affect the cellular mechanisms of fungal growth. Asignificant reduction of the fungal biomass was observed in the presence of millimolar zinc concentrations; this mirrored conspicuous changes in hyphal morphology which led to apical swellings and increased branching in the subapical parts. Specific probes for fluorescence and electron microscopy localised chitin, the main cell wall polysaccharide, on the inner part of the fungal wall and on septa in control specimens. In Zn-treated mycelium, hyphal walls were thicker and a more intense chitin labelling was detected on the transverse walls. Aquantitative assay showed a significant increase in the amount of chitin in metal- treated hyphae

Validation of an Emission Model for a Marine Diesel Engine with Data from Sea Operations

In this study, a model is developed to simulate the dynamics of an internal combustion engine, and it is calibrated and validated against reliable experimental data, making it a tool that can effectively be adopted to conduct emission predictions. In this work, the Ricardo WAVE software is applied to the simulation of a particular marine diesel engine, a four-stroke engine used in the maritime field. Results from the bench tests are used for the calibration of the model. Finally, the calibration of the model and its validation with full-scale data measured at sea are presented. The prediction includes not only the classic engine operating parameters for a comparison with surveys but also an estimate of nitrogen oxide emissions, which are compared with similar results obtained with emission factors. The calibration of the model made it possible to obtain an overlap between the simulation results and real data with an average error of approximately 7% on power, torque, and consumption. The model provides encouraging results, suggesting further applications, such as in the study on transient conditions, coupling of the engine model with the ship model for a complete simulation of the operating conditions, and optimization studies on consumption and emissions. The availability of the emission data during the sea trial and validated simulation results are the strengths and novelties of this work

Bacterial community analysis on the Mediaeval stained glass window "Natività" in the Florence Cathedral

Microbial corrosion of glass causes problems on delicates antique glass samples. Until now, the effect of microbial activity on corrosion phenomena has not been well documented. Only a few studies have been published concerning the microflora growing on glass surfaces. The present study deals with the characterization of cultivable aerobic bacteria isolated from the historical glass window "Natività" in the Florence Cathedral, designed by Paolo Uccello and realized by Angelo Lippi between 1443 and 1444. Microbial strains were sampled from four of the 25 panels of the "Natività" in the occasion of a recent conservation treatment, due to the presence of various kinds of crusts. One hundred microorganisms were isolated, about 50% bacteria and 50% fungi. Bacteria were submitted to morphological characterization and classified in the Gram group. For twenty strains, from different glass panels, the 16S rDNA gene was amplified and sequenced. Sequence analysis showed genus Bacillus, Arthrobacter and Paenibacillus as the most representative. In particular Bacillus and Paenibacillus are crusts associated. Phylogenetic relationship among isolates was determined. Chemical analysis of the glass and crusts completed the study

Sensitivity of surface fluxes in the ECMWF land surface model to the remotely sensed leaf area index and root distribution: Evaluation with tower flux data

The surface-atmosphere turbulent exchanges couple the water, energy and carbon budgets in the Earth system. The biosphere plays an important role in the evaporation process, and vegetation related parameters such as the leaf area index (LAI), vertical root distribution and stomatal resistance are poorly constrained due to sparse observations at the spatio-temporal scales at which land surface models (LSMs) operate. In this study, we use the Carbon Hydrology Tiled European Center for Medium-Range Weather Forecasts (ECMWF) Scheme for Surface Exchanges over Land (CHTESSEL) model and investigate the sensitivity of the simulated turbulent fluxes to these vegetation related parameters. Observed data from 17 FLUXNET towers were used to force and evaluate model simulations with different vegetation parameter configurations. The replacement of the current LAI climatology used by CHTESSEL, by a new high-resolution climatology, representative of the station’s location, has a small impact on the simulated fluxes. Instead, a revision of the root profile considering a uniform root distribution reduces the underestimation of evaporation during water stress conditions. Despite the limitations of using only one model and a limited number of stations, our results highlight the relevance of root distribution in controlling soil moisture stress, which is likely to be applicable to other LSMs

Psychometric properties and diagnostic accuracy of the short form of the geriatric anxiety scale (GAS-10)

Background: Anxious symptoms have a negative impact on different aspects of the elderly\u2019s quality of life, ranging from the adoption of unhealthy lifestyle behaviours to an increased functional impairment and a greater physical disability. Different brief assessment instruments have been developed as efficacy measures of geriatric anxiety in order to overcome psychometric weaknesses of its long form. Among these, the 10-item Geriatric Anxiety Scale (GAS-10) showed strong psychometric properties in community-dwelling samples. However, its diagnostic accuracy is still unexplored, as well as its discriminative power in clinical samples. Methods: In the present study, we explored the psychometric performance of the GAS-10 in the elderly through Item Response Theory in a sample of 1200 Italian community-dwelling middle-aged and elderly adults (53.8% males, mean age = 65.21 \ub1 9.19 years). Concurrent validity, as well as diagnostic accuracy, was examined in a non-clinical sample (N = 229; 46.72% males) and clinical sample composed of 35 elderly outpatients (74.28% females) with Generalized Anxiety Disorder (GAD). Results: The GAS-10 displayed good internal construct validity, with unidimensional structure and no local dependency, good accuracy, and no signs of Differential Item Functioning (DIF) or measurement bias due to gender, but negligible due to the age. Differences in concurrent validity and diagnostic accuracy among the long form version of the GAS and the GAS-10 were not found significant. The GAS-10 may be more useful than the longer versions in many clinical and research applications, when time constraints or fatigue are issues. Conclusion: Using the ROC curve, the GAS-10 showed good discriminant validity in categorizing outpatients with GAD disorder, and high anxiety symptoms as measured by the GAS-SF cut-off. The stable cut-off point provided could enhance the clinical usefulness of the GAS-10, which seems to be a promising valid and reliable tool for maximize diagnostic accuracy of geriatric anxiety symptoms