93 research outputs found

    A graphical method for performance mapping of machines and milling tools

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    Optimal design of the machining setup in terms of installed machines, cutting tools and process parameters is of paramount importance for every manufacturing company. In most of the metal cutting companies, all choices related to machine eligibility and cutting parameters selection typically come from heuristic approaches and follow supplier indications or base on the skill of experienced machine operators. More advanced solutions, such as model-based and virtual approaches, are adopted less frequently mainly due to the lack of these techniques in grasping the underlying knowledge successfully. Aim of this work is to introduce a synthetic graphical representation of machining centers and cutting tools capabilities, to provide an accessible way to evaluate the feasibility and close-to-limit conditions of the cutting process. Taking inspiration from previous scientific works from the measurement engineering field, a set of 2D and 3D graphs are presented to map machine, tools and process capabilities, as well as their obtainable manufacturing performances and expectable tool life. This approach synthesizes the nominal data coming from different sources (catalogues, database, tool model geometries etc.) and the real cutting tools parameters used during the production phase. Some examples are provided to show the potential of this graphical evaluation in supporting process planning and decision-making and in formalizing the machining setup knowledge. Further developments are devoted to extend the method to other manufacturing processes, including hybrid processes. At the same time, an in-process data gathering software will be integrated for building a solid database that can be used by an autonomous multi-technological process selector, as well as by a pre-process condition advisor in an Industry 4.0 oriented way

    Syncope in the elderly: An update

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    Abstract Syncope in the elderly is an extremely prevalent clinical condition characterized by high mortality and presence of recurrences. The diagnosis of syncope in the elderly is sometimes difficult and multidimensional geriatric assessment should be carefully administered. Diagnostic algorithms should be applied with attention, although unknown syncope is still frequent. The therapeutic approach to syncope in the elderly is complicated by the high prevalence of neurally-mediated syncope, in which the therapeutic approach is still unknown. The establishment of a "Syncope Unit" has certainly improved the diagnostic-therapeutic approach to patients with syncope, especially in old age where the management is extremely difficult

    Molecular Physics of Elementary Processes relevant to Hypersonics: atom-molecule, molecule-molecule and atom-surface processes.

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    In the present chapter some prototype gas and gas-surface processes occurring within the hypersonic flow layer surrounding spacecrafts at planetary entry are discussed. The discussion is based on microscopic dynamical calculations of the detailed cross sections and rate coefficients performed using classical mechanics treatments for atoms, molecules and surfaces. Such treatment allows the evaluation of the efficiency of thermal processes (both at equilibrium and nonequilibrium distributions) based on state-to-state and state specific calculations properly averaged over the population of the initial states. The dependence of the efficiency of the considered processes on the initial partitioning of energy among the various degrees of freedom is discussed

    Effect of the embedment of carbon doped nanocomposites in a real matrix on the enhanced photocatalytic activity

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    Solar light can be used by semiconductor nanocrystals as a free and largely available source of energy to transform air pollutants into non-volatile less harmful chemicals. The efficiency of this process can be enhanced by doping the semiconductor with carbon-based materials, such as graphene. Nevertheless, such an increased activity has been reported (i) for nanocomposite photocatalysts produced on the research laboratory scale, (ii) analyzing their performance as self-standing photocatalysts and not after incorporation into “real” matrixes (e.g. building materials) and (iii) typically using model target pollutants instead of “real” hazardous ones. Here we describe the large-scale preparation of two series of carbon based photocatalysts starting from commercial materials and we demonstrate their superior photocatalytic activity in degrading important air pollutants as nitrogen oxides, compared to undoped photocatalysts. The photocatalytic activity was evaluated by NOx abatement adopting the continuous flow procedure and the apparatus reported in the Italian standard UNI 11,247. Best performing materials were incorporated into two different inorganic matrixes (cement and lime). In both cases, the superior photocatalytic performances were maintained. An improvement up to 42±7% of the photocatalytic activity was measured in the case of a cement sample for a carbon-doped photocatalyst with respect to bare TiO2 . The materials were characterized by UV-Vis spectroscopy, high resolution powder X-ray diffraction (HR-PXRD), high-resolution scanning electron microscopy (HR-SEM) energy-dispersive X-ray spectroscopy (EDS) and micro-Raman

    Does Clinical Governance influence the quality of medical records?

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    Background. Clinical Governance (CG) is a validated framework for continuous quality improvement in health care settings. Quality medical records may reflect the quality of care delivered and are a viable tool to implement CG skills. Aim. Aim of this study is to investigate the correlation between the level of implementation of CG dimensions and the quality of medical records. Material and methods. A cross-sectional study was carried out in an Italian Teaching Hospital. CG implementation levels were quantified through a systematic methodology (OPTIGOV©). The overall quality of medical records was measured through a revised version of a National-validated scale. A multiple linear regression model was used to test the likely influence of all the variables constituting the OPTIGOV evaluation on the quality of medical records. 47 hospital wards and 1458 medical records were assessed. Results. A significant and positive association between the quality of medical records and the accountability score (β = 0.15; p < 0.01) and the clinical audit score (b = 0.11; p = 0.02), was found. Conversely, the risk management score shown a negative and significant correlation (b = -0.17; p < 0.01). This study confirms that CG plays a central role in driving quality improvement and advocates a systematic implementation of such an approach within healthcare organizations.

    Management of Low-Risk Thyroid Cancers: Is Active Surveillance a Valid Option? A Systematic Review of the Literature.

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    Thyroid cancer is the most common endocrine malignancy, representing 2.9% of all new cancers in the United States. It has an excellent prognosis, with a five-year relative survival rate of 98.3%.Differentiated Thyroid Carcinomas (DTCs) are the most diagnosed thyroid tumors and are characterized by a slow growth rate and indolent course. For years, the only approach to treatment was thyroidectomy. Active surveillance (AS) has recently emerged as an alternative approach; it involves regular observation aimed at recognizing the minority of patients who will clinically progress and would likely benefit from rescue surgery. To better clarify the indications for active surveillance for low-risk thyroid cancers, we reviewed the current management of low-risk DTCs with a systematic search performed according to a PRISMA flowchart in electronic databases (PubMed, Web of Science, Scopus, and EMBASE) for studies published before May 2021. Fourteen publications were included for final analysis, with a total number of 4830 patients under AS. A total of 451/4830 (9.4%) patients experienced an increase in maximum diameter by &gt;3 mm; 609/4830 (12.6%) patients underwent delayed surgery after AS; metastatic spread to cervical lymph nodes was present in 88/4213 (2.1%) patients; 4/3589 (0.1%) patients had metastatic disease outside of cervical lymph nodes. Finally, no subject had a documented mortality due to thyroid cancer during AS. Currently, the American Thyroid Association guidelines do not support AS as the first-line treatment in patients with PMC; however, they consider AS to be an effective alternative, particularly in patients with high surgical risk or poor life expectancy due to comorbid conditions. Thus, AS could be an alternative to immediate surgery for patients with very-low-risk tumors showing no cytologic evidence of aggressive disease, for high-risk surgical candidates, for those with concurrent comorbidities requiring urgent intervention, and for patients with a relatively short life expectancy

    Aquatic Angiosperm Transplantation: A Tool for Environmental Management and Restoring in Transitional Water Systems

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    Since the 1960s, the Venice Lagoon has suffered a sharp aquatic plant constriction due to eutrophication, pollution, and clam fishing. Those anthropogenic impacts began to decline during the 2010s, and since then the ecological status of the lagoon has improved, but in many choked areas no plant recolonization has been recorded due to the lack of seeds. The project funded by the European Union (LIFE12 NAT/IT/000331-SeResto) allowed to recolonize one of these areas, which is situated in the northern lagoon, by widespread transplantation of small sods and individual rhizomes. In-field activities were supported by fishermen, hunters, and sport associations; the interested surface measured approximately 36.6 km2. In the 35 stations of the chosen area, 24,261 rhizomes were transplanted during the first year, accounting for 693 rhizomes per station. About 37% of them took root in 31 stations forming several patches that joined together to form extensive meadows. Plant rooting was successful where the waters were clear and the trophic status low. But, near the outflows of freshwater rich in nutrients and suspended particulate matter, the action failed. Results demonstrate the effectiveness of small, widespread interventions and the importance of engaging the population in the recovery of the environment, which makes the action economically cheap and replicable in other similar environments

    An Integrated Approach for Evaluating the Restoration of the Salinity Gradient in Transitional Waters: Monitoring and Numerical Modeling in the Life Lagoon Refresh Case Study

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    Large lagoons usually show a salinity gradient due to fresh water tributaries with inner areas characterized by lower mean values and higher fluctuation of salinity than seawaterdominated areas. In the Venice Lagoon, this ecotonal environment, characterized in the past by oligo‐mesohaline waters and large intertidal areas vegetated by reedbeds, was greatly reduced by historical human environmental modifications, including the diversion of main rivers outside the Venice Lagoon. The reduction of the fresh water inputs caused a marinization of the lagoon, with an increase in salinity and the loss of the related habitats, biodiversity, and ecosystem services. To counteract this issue, conservation actions, such as the construction of hydraulic infrastructures for the introduction and the regulation of a fresh water flow, can be implemented. The effectiveness of these actions can be preliminarily investigated and then verified through the combined implementation of environmental monitoring and numerical modeling. Through the results of the monitoring activity carried out in Venice Lagoon in the framework of the Life Lagoon Refresh (LIFE16NAT/IT/000663) project, the study of salinity is shown to be a successful and robust combination of different types of monitoring techniques. In particular, the characterization of salinity is obtained by the acquisition of continuous data, field campaigns, and numerical modeling

    CrowdSenSim: a Simulation Platform for Mobile Crowdsensing in Realistic Urban Environments

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    Smart cities take advantage of recent ICT developments to provide added value to existing public services and improve quality of life for the citizens. The Internet of Things (IoT) paradigm makes the Internet more pervasive where objects equipped with computing, storage and sensing capabilities are interconnected with communication technologies. Because of the widespread diffusion of IoT devices, applying the IoT paradigm to smart cities is an excellent solution to build sustainable Information and Communication Technology (ICT) platforms. Having citizens involved in the process through mobile crowdsensing (MCS) techniques augments capabilities of these ICT platforms without additional costs. For proper operation, MCS systems require the contribution from a large number of participants. Simulations are therefore a candidate tool to assess the performance of MCS systems. In this paper, we illustrate the design of CrowdSenSim, a simulator for mobile crowdsensing. CrowdSenSim is designed specifically for realistic urban environments and smart cities services. We demonstrate the effectiveness of CrowdSenSim for the most popular MCS sensing paradigms (participatory and opportunistic) and we present its applicability using a smart public street lighting scenario
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