The MURAVES muon telescope: technology and expected performances

The MURAVES project aims to study the inner structure of the upper part of the Mt. Vesuvius volcano by muon radiography (muography) technique. Very high energy muons, produced by cosmic rays in the at- mosphere, can penetrate large thickness of rocks. By measuring the at- tenuation of the muons flux trough the volcano cone is possible to obtain a 2D image of the density structure. Internal discontinuities, with a spa- tial resolution of about 10 m, can be, in principle, resolved. An absolute average density measurement can be provided too. The project, funded by the Italian Ministry of University, Research and Education (MIUR), is led by INGV and INFN. In this article the mechanical structure of the de- tectors and background suppression techniques are reported

Surface micro and nanostructuring of three-dimensional components of micro medical devices

Surface structuring of medical implants has been shown to reduce the rejection rate of medical devices inserted inside living tissue. Several studies have shown that by texturing the surface of medical implants at micro/nanoscale it is possible to foster cell adhesion. The surface texturing of medical devices poses many challenges in terms of cost and time when the nano texturing process is performed directly on the part surface. A viable solution for mass production of polymer based surface enhanced medical devices is achieved via injection molding. However, nano structuring of micro injection molding molds, requires techniques enabling processing of complex surfaces, small curvature radii and with high aspect ratios. Furthermore the accessibility of all surfaces to be structured and the processing time are the main concerns and limiting factors on the selection of the structures dimensions and geometries. In this work, two different process chains are analyzed for the nano structuring of a bone micro plug. The first method relies on a chemical deposition process in order to produce a semi random structure on the entire mold surface of the medical component. The characteristic size of the structures is controlled by acting on the deposition parameters. The second process, relies on laser structuring of the mold components by producing Laser-Induced Periodic Surface Structures (LIPSS).The two process chains are compared and an evaluation of the applicability in different production scenarios presented, with specific focus on surface accessibility, nano structures uniformity and applicability to surfaces with complex geometr

Effects of Surface Treatments on the Fatigue Response of High Strength Fasteners

The aim of the present work was the assessment of the impact of deep-rolling and shot-peening performed in the underhead and in the unthreaded shank of two high strength screws (36 NiCrMo and 42 CrMoV) for fatigue life enhancement. The experimental campaign consisted of six combinations, including the non-treated state. The aforementioned treatments were evaluated alone or with shot-peening performed after deep-rolling in the underhead fillet of the screws. Deep rolling was carried out at the optimal rolling force, whereas two shot diameters were considered for shot-peening (Z100 and UFS70). The results have been evaluated in terms of fatigue limits and factor effects have been assessed by marginal mean plots

Assessment of fiber orientation models predictability by comparison with X-ray µCT data in injection-molded short glass fiber-reinforced polyamide

The distribution of fibers in injection molded thermoplastic-reinforced parts is known to significantly affect both the final mechanical properties and the appearance of defects related to undesired shrinkages and warpages. Even if the numerical modelling of the process is in the state-of-the-art, the selection criteria of the model for the fiber orientation predictability and the influence of the models’ parameters are not yet clearly understood. The complexity of the matter increases further considering that, inside the same injection molded part, the fiber orientation distribution could differ from one region to another depending on the local melt shear-flow type. In this context, the aim of this study is to investigate the orientation of fibers in regions of non-simple shear flow in an injection molded short glass fiber reinforced part. X-ray micro-computed tomography is used to experimentally investigate fiber distribution and orientation. Furthermore, a number of numerical simulations of the injection molding process are performed in Moldflow® by varying the mesh type (2D/3D), the selected predictive model and the models’ coefficients. The main findings indicates that, in regions with non-simple shear flow, a 2D mesh fails to capture accurate fiber orientation. A 3D mesh is essential for reliable predictions. MRD-specific parameters from the literature reduce prediction error by 37.5% compared to Moldflow's default MRD parameters. Regarding the RSC model, both Wang’s optimal retarding rate parameter and AMI's default retarding rate parameter result in similar 5% prediction errors. However, employing a literature-suggested interaction coefficient raises the prediction error to 26%

Visual Function and Ophthalmological Findings in CHARGE Syndrome: Revision of Literature, Definition of a New Clinical Spectrum and Genotype Phenotype Correlation

CHARGE syndrome (CS) is a rare genetic disease causing multiple anatomical defects and sensory impairment. Visual function is usually reported by caregivers and has never been described with a structured behavioral assessment. Our primary objective was to describe ocular abnormalities, visual function and genotype–ocular-phenotype correlation in CS. A prospective monocentric cohort study was performed on 14 children with CS carrying pathogenic CHD7 variants. All children underwent ophthalmological evaluation and structured behavioral assessment of visual function. The VISIOCHARGE questionnaire was administered to parents. Colobomas were present in 93% of patients. Genotype–phenotype correlation documented mitigated features in a subset of patients with intronic pathogenic variants predicted to affect transcript processing, and severe features in patients with frameshift/nonsense variants predicting protein truncation at the N-terminus. Abnormal visual function was present in all subjects, with different degrees of impairment. A significant correlation was found between visual function and age at assessment (p-value = 0.025). The present data are the first to characterize visual function in CS patients. They suggest that hypomorphic variants might be associated with milder features, and that visual function appears to be related to age. While studies with larger cohorts are required for confirmation, our data indicate that experience appears to influence everyday use of visual function more than ocular abnormalities do

Muography of the Volcanic Structure of the Summit of Vesuvius, Italy

In the context of recent developments in volcanic muography, we describe an experiment at Vesuvius, the volcano near Naples that destroyed Pompeii and Herculaneum (Italy) in 79 CE. This volcano is about 1,200 m high with a typical summit caldera formed by Mount Somma. Vesuvius is among the highest-risk volcanoes in the world due to its highly explosive eruptive style and the high population density of the area where it is located. Volcanoes are generally fragile geological structures, prone to produce partial collapse and large landslides that can affect the style of eruptions. Moreover, the knowledge of the internal structure is fundamental for understanding past eruption activity and for constraining eruption models. For these reasons, studying the internal structure of the “Gran Cono” (great cone) of Vesuvius and the physical characteristics of its rock is important and led us to design a muography experiment at Vesuvius. This experiment, which is currently in progress, is based on three scintillator detectors with a surface of 1 m 2 each. These detector features have been implemented to overcome the problems related to the large thickness of rock that form the “Gran Cono” of Vesuvius and the effects that can be a source of error in data processing. These aspects represent an open challenge for the muography of large volcanoes, which today constitutes the frontier of research in the field of volcanic muography