1,721,032 research outputs found
Second harmonic beam shaping and sensing in dielectric bow-tie antenna via convex optimization array synthesis approach
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Apparent and root causes of occupational accidents occurred during maintenance interventions
No full textThis paper introduces the results of a structured analysis of occupational accidents occurred during maintenance interventions in Italy, in the last decades. The investigation includes 49 occupational accidents occurred in Italy between 2002 and 2016, involving maintenance workers. Results show that the leading apparent cause of accidents was the voluntary adoption of an improper procedure, e.g. the bypass of a risk control measure, followed by distraction and error of judgment. The lack of training appeared to be the leading root cause of the investigated events. However, the investigation of root causes was difficult because of the lack of information on human factors and other intermediate causes that lead to the occupational accident. The findings of this analysis suggest that a structured methodology for accident registration is required. Such methodology should collect data supporting the identification of the root causes of occupational accidents and workers’ reasonably foreseeable behaviors on which prevention strategies should focus
Solving 1D Inverse Scattering Problem for Media and Materials Profiling
No full textThe inverse problem at hand tackles the reconstruction of the dielectric profile of a slab. To this end, single-view multi-frequency configuration is exploited, wherein the scattered field can be collected in reflection (single antenna) and in transmission (two antennas) mode. As it is well known, besides being ill-posed, the problem is also non-linear, thus requiring local or global optimization schemes which could be trapped into false solutions. This drawback is completely avoided if inversion methods based on some classical linear scattering models are employed. However, by doing so, the cost to pay is that the class of retrievable profiles for which they work is extremely narrow. In this contribution we analyse a possible effective strategy to enlarge the class of retrievable profiles
Warping-based co-registration of thermal infrared images: Study of factors influencing its applicability
Full text linkA relevant issue for processing biomedical thermal imaging data is the availability of tools for objective and quantitative comparison of images across different conditions or subjects. To this goal, a solution can be offered by projecting the thermal distribution data onto a fictitious template to obtain a common reference for comparison across cases or subjects.
In this preliminary study, we tested the feasibility of applying a warping procedure on infrared thermal images. Fifteen thermal images of checkerboard were recorded at three different distances and five different angles in order to evaluate which factor mostly influences the warping accuracy.
The accuracy of three different warping transformation models (local weighted mean (LWM), polynomial, affine) was tested by comparing the positioning error between users’ selected fiduciary points on each thermal image and their corresponding reference position assigned on the template image.
Fifteen users, divided into three groups upon on their experience in thermal imaging processing, participated in this study in order to evaluate the effect of experience in applying a warping procedure to the analysis of thermal infrared images.
The most relevant factor influencing the positioning and thermal errors is the acquisition distance, while the users’ level of experience and the inclination angle do not seem to play the same importance. Comparing the three transformations, the LWM seems to be the best in terms of minimizing the two categories of errors. This preliminary work helps to understand the limits and the possibilities of applying warping techniques for objective, quantitative and automatic thermal image comparisons
Linear One-dimensional Inverse Profiling: The Role of a Reflecting Plane in the Background
No full textIn this paper, a one dimensional inverse profiling problem under a linearised framework is addressed. The aim is to establish the role played by a reflecting plane located in the scattering scenario on the profile reconstructions by studying its impact on the singular values of the scattering operator. It is shown that in presence of reflecting plane, the singular values exhibit a step-like behavior and the Number of Degree of Freedom (NDF) is twice as large as the NDF in homogeneous medium. This entails an enlargement of the class of dielectric profiles that can be reliably reconstructed
Applicazione delle direttive ATEX per la valutazione del rischio esplosione in una officina farmaceutica
No full textNella maggioranza dei processi industriali, possono essere presenti ambienti sospetti di
inquinamento con ad esempio polveri o sostanze volatili combustibili che, se innescate,
possono provocare un’esplosione. Per garantire la sicurezza in tali impianti e gli ambienti
ad essi associati, la comunit europea ha emanato direttive che fissano i requisiti da
applicare a tutti gli equipaggiamenti istallati in ambienti potenzialmente esplosivi.
Nel caso di una officina farmaceutica spesso possono presentarsi situazioni pericolose,
dovute appunto a zone inquinate che possono portare ad un rischio di esplosione. Questo
lavoro intende illustrare una possibile procedura di valutazione basata sull’analisi FMEA al
fine di identificare il componente pi critico per le attrezzature analizzate.
Tramite il tasso di guasto del componente, tenendo conto della zona e del tasso di
inquinamento stata inoltre definita la probabilit di innesco efficace che moltiplicata per
la probabilit di avere atmosfera esplosiva ha portato ad ottenere il fattore di probabilit
totale. In funzione della cifra di rischio complessiva sono state quindi stabilite le misure
protettive da adottare.
In ultima analisi un elenco di interventi migliorativi e una stima dei costi stata eseguita
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