3,986 research outputs found

    Strain-based method for fatigue failure analysis of truss lattice structures: modeling and experimental setup

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    Lattice structures, as a subclass of cellular solids, are nowadays among the most promising materials when it comes to lightweight engineering: their excellent mechanical properties, together with their functionality and reduced mass, make them the perfect candidates for many applications in the aerospace and automotive fields. Such sectors require though demanding specifications for their components: among all, fatigue resistance is extremely important. A simplified method for the fatigue analysis of lattice structures, based on finite element method (FEM) is proposed: through linear homogenization of the lattice structure, a lighter FEM model employed for the fatigue failure analysis is developed. Second step of the model is the application of de-homogenization on the most critical cell and therefore the recovery of the true state of the lattice. In this investigation, the method is employed in the case of a 4-point bending cyclic load, together with the presentation of a validating experimental setup

    A New Ensemble Probabilistic Method for Short-Term Photovoltaic Power Forecasting

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    The high penetration of photovoltaic (PV) systems led to their growing impact on the planning and operation of actual distribution systems. However, the uncertainties due to the intermittent nature of solar energy complicate these tasks. Therefore, high-quality methods for forecasting the PV power are now essential, and many tools have been developed in order to provide useful and consistent forecasts. This chapter deals with probabilistic forecasting methods of PV system power, since they have recently drawn the attention of researchers as appropriate tools to cope with the unavoidable uncertainties of solar source. A new multi-model probabilistic ensemble is proposed; it properly combines a Bayesian-based and a quantile regression-based probabilistic method as individual predictors. Numerical applications based on actual irradiance data give evidence of the probabilistic performances of the proposed method in terms of both sharpness and calibration

    Reducing parasitic resonances in particle accelerators components by broadband Higher Order Mode couplers

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    In particle accelerator components, parasitic resonances must be reduced because they heat up the equipment and cause beam instabilities. In this paper, a method for designing and characterizing Higher Order Mode (HOM) couplers for reducing such resonances in a broad bandwidth is proposed. A case study is considered for a specific component, called QuattroTank, showing geometrical discontinuities and thus causing significant electro-magnetic resonances. Results of numerical simulation and experimental emulation prove the capability of the proposed method to reduce the peaks and the $Q-factor of the resonances

    Dolphin Morbillivirus in Eurasian Otters, Italy

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    We report biomolecular evidence of dolphin morbillivirus in 4 wild Eurasian otters (Lutra lutra) from southern Italy; 2 animals showed simultaneous immunohistochemical reactivity against morbilliviral antigen. These cases add further concern and support to the progressively expanding host range of dolphin morbillivirus in the western Mediterranean Sea

    Work-related noise exposure in a cohort of patients with chronic tinnitus: analysis of demographic and audiological characteristics

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    Work-related noise exposure is one of the major factors contributing to the development of adult-onset hearing loss and tinnitus. The aim of this study was to analyze, in patients with chronic tinnitus and long-term occupational noise exposure, (A) characteristics of hearing loss, tinnitus, comorbidities, demographic characteristics and a history of work-related noise exposure and (B) differences among individuals employed in occupations with high and low risk of developing work-related noise-induced hearing loss (NIHL). One hundred thirty six patients with chronic tinnitus and at least a 10 year-long working history were divided into two groups based on the risk of their profession to induce NIHL. Individuals employed in jobs at high risk for NIHL were mostly males and exhibited a poorer hearing threshold, more evident in the left ear. Tinnitus was mostly bilateral; the next largest presentation was left-sided; patients described their tinnitus as buzzing or high-pitched. Correlation between age, length of tinnitus and worse hearing was found. Patients with a higher degree of hearing impairment were mostly males and were more likely to have a family history of hearing loss and at least one cardiovascular comorbidity. Our study shows some differences in individuals with tinnitus and a history of a profession associated with increased exposure to NIHL compared to those without such a history

    Emergency surgery in a severe penetrating skull base injury by a screwdriver: case report and literature review

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    BACKGROUND: Very few cases of severe penetrating injuries to the skull base with a seemingly innocuous object have been described in the literature. Of the cases reported, only ten involve a penetrating screwdriver. However, the choice of therapeutic management, whether it be emergency surgical or non-surgical removal of the penetrating object as well as the selected surgical approach remain quite controversial. CASE PRESENTATION: The authors describe the case of a severe penetrating skull base injury caused by a screwdriver, following an accidental fall from a ladder. The patient was admitted in Glasgow Coma Scale (GCS) 11 with a cerebrospinal fluid (CSF) leak in the right maxillary area. The tri-dimensional computerized tomography (3-D CT) scan revealed an oblique trajectory of the screwdriver shank through the skull base. The authors opted for an emergency surgical extraction of the object. A contra-lateral pterional approach was successfully performed and a two-year follow-up showed no neurological deficits. CONCLUSION: The reported case supports the choice of emergency surgical removal of the object in penetrating skull base injuries involving the anterior skull base with neurovascular lesions. Surgical aspects of the pterional approach, and in particular the left pterional approach as well as other cranio-facial approaches in severe penetrating skull base injuries are discussed

    Assessment and Scientific Progresses in the Analysis of Olfactory Evoked Potentials

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    The human sense of smell is important for many vital functions, but with the current state of the art, there is a lack of objective and non-invasive methods for smell disorder diagnostics. In recent years, increasing attention is being paid to olfactory event-related potentials (OERPs) of the brain, as a viable tool for the objective assessment of olfactory dysfunctions. The aim of this review is to describe the main features of OERPs signals, the most widely used recording and processing techniques, and the scientific progress and relevance in the use of OERPs in many important application fields. In particular, the innovative role of OERPs is exploited in olfactory disorders that can influence emotions and personality or can be potential indicators of the onset or progression of neurological disorders. For all these reasons, this review presents and analyzes the latest scientific results and future challenges in the use of OERPs signals as an attractive solution for the objective monitoring technique of olfactory disorder
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