302 research outputs found

    Statistical properties of acoustic emission signals from metal cutting processes

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    Acoustic Emission (AE) data from single point turning machining are analysed in this paper in order to gain a greater insight of the signal statistical properties for Tool Condition Monitoring (TCM) applications. A statistical analysis of the time series data amplitude and root mean square (RMS) value at various tool wear levels are performed, �nding that ageing features can be revealed in all cases from the observed experimental histograms. In particular, AE data amplitudes are shown to be distributed with a power-law behaviour above a cross-over value. An analytic model for the RMS values probability density function (pdf) is obtained resorting to the Jaynes' maximum entropy principle (MEp); novel technique of constraining the modelling function under few fractional moments, instead of a greater amount of ordinary moments, leads to well-tailored functions for experimental histograms.Comment: 16 pages, 7 figure

    Retentive device for intravesical drug delivery based on water-induced shape memory response of poly(vinyl alcohol): design concept and 4D printing feasibility

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    The use of shape memory polymers exhibiting water-induced shape recovery at body temperature and water solubility was proposed for the development of indwelling devices for intravesical drug delivery. These could be administered via catheter in a suitable temporary shape, retained in the bladder for a programmed period of time by recovery of the original shape and eliminated with urine following dissolution/erosion. Hot melt extrusion and fused deposition modeling 3D printing were employed as the manufacturing techniques, the latter resulting in 4D printing because of the shape modifications undergone by the printed item over time. Pharmaceutical-grade poly(vinyl alcohol) was selected based on its hot-processability, availability in different molecular weights and on preliminary data showing water-induced shape memory behavior. Specimens having various original and temporary geometries as well as compositions, successfully obtained, were characterized by differential scanning calorimetry and dynamic-mechanical thermal analysis as well as for fluid uptake, mass loss, shape recovery and release behavior. The samples exhibited the desired ability to recover the original shape, consistent in kinetics with the relevant thermo-mechanical properties, and concomitant prolonged release of a tracer. Although preliminary in scope, this study indicated the viability of the proposed approach to the design of retentive intravesical delivery systems

    Atherosclerosis and rheumatoid arthritis : more than a simple association

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    In the last decades a large amount of evidences linked rheumatoid arthritis (RA) to atherosclerosis. In particular, it is well established that RA patients have an increased risk of cardiovascular events that is not fully explained by smoke and other classic cardiovascular risk factors. In fact, RA and atherosclerosis may share several common pathomechanisms; inflammation undoubtedly plays a primary role in these settings, being involved in the appearance and progression of both diseases. In fact, proinflammatory cytokines such as tumor necrosis factor alpha and interleukin-6, involved in the pathogenesis of RA, are also independently predictive of subsequent cardiovascular disease (CVD) events in these patients. In RA inflammation may alter HDL constituents and the concentration of LDL and HDL, thus facilitating atherosclerosis and CVD events. On the other hand, also the increase of oxidative processes, frequently observed in RA, may induce atherosclerosis. Interestingly some genetic polymorphisms associated with RA occurrence may enhance atherosclerosis, thus confirming the link between these diseases; however there are some polymorphisms associated with RA susceptibility which do not increase CVD risk; this behavior is a further confirmation that several mechanisms may influence atherosclerotic processes in RA. Moreover, atherosclerosis may be directly mediated also by underlying autoimmune processes, and indirectly by the occurrence of metabolic syndrome and impaired physical activity. Finally, the effects of RA therapies on cardiovascular system in general and on atherosclerosis in particular, are really wide and different. Therefore, RA treatment comprehends drugs that may either increase or reduce CVD. However, the starting point of every RA treatment is that disease control, or better remission, is the best way we have for the reduction of cardiovascular morbidity and mortality in these patients

    Software engineering processes for self-adaptive systems

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    In this paper, we discuss how for self-adaptive systems some activities that traditionally occur at development-time are moved to run-time. Responsibilities for these activities shift from software engineers to the system itself, causing the traditional boundary between development-time and run-time to blur. As a consequence, we argue how the traditional software engineering process needs to be reconceptualized to distinguish both development-time and run-time activities, and to support designers in taking decisions on how to properly engineer such systems. Furthermore, we identify a number of challenges related to this required reconceptualization, and we propose initial ideas based on process modeling. We use the Software and Systems Process Engineering Meta-Model (SPEM) to specify which activities are meant to be performed off-line and on-line, and also the dependencies between them. The proposed models should capture information about the costs and benefits of shifting activities to run-time, since such models should support software engineers in their decisions when they are engineering self-adaptive systems

    Active Subjects with Autoimmune Type 1 Diabetes Have Better Metabolic Profiles than Sedentary Controls

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    Previous studies in humans with type 1 diabetes (T1D) and in non-obese diabetic mice have investigated the beneficial immunomodulatory potential of aerobic physical activity. Performing high volume of aerobic exercise may favorably regulate autoimmunity in diabetes. We tested whether increased physical activity is a self-sufficient positive factor in T1D subjects. During a 3-month observational period, active (6M; 40.5\ub16.1 years; BMI 24.5\ub12.1) and sedentary (4M, 3F; 35.9\ub18.9 years; BMI 25.7\ub13.8) T1D individuals on insulin pump therapy were studied for metabolic, inflammatory and autoimmune parameters. At baseline and at the end of a 3-month period, glycosylated hemoglobin (HbA1c), auto-antibodies (anti-GAD, anti-ZnT8, anti-IA2, ICA) and pro-inflammatory cytokines (IL-6 and TNF-\u3b1) were evaluated. During the 3rd month of the period, physically active T1D patients showed a significant reduction in the average glucose levels (-9%, p=0.025, by CGM) compared to the 1st-month values, and even their hyperglycemic episodes (>180mg/dL) diminished significantly (-24.2%, p=0.032 vs 1st month). Moreover, active T1D subjects exhibited an improved body composition with respect to sedentary controls. No significant changes were detected as to the autoimmune and inflammatory profiles. This study confirms the beneficial role of physical exercise associated with insulin pump therapy in order to improve metabolic control in individuals with T1D. These preliminary positive observations need to be challenged in a prolonged interventional follow-up

    A unifying perspective on protocol mediation: interoperability in the Future Internet

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    Given the highly dynamic and extremely heterogeneous software systems composing the Future Internet, automatically achieving interoperability between software components —without modifying them— is more than simply desirable, it is quickly becoming a necessity. Although much work has been carried out on interoperability, existing solutions have not fully succeeded in keeping pace with the increasing complexity and heterogeneity of modern software, and meeting the demands of runtime support. On the one hand, solutions at the application layer target higher automation and loose coupling through the synthesis of intermediary entities, mediators, to compensate for the differences between the interfaces of components and coordinate their behaviours, while assuming the use of the same middleware solution. On the other hand, solutions to interoperability across heterogeneous middleware technologies do not reconcile the differences between components at the application layer. In this paper we propose a unified approach for achieving interoperability between heterogeneous software components with compatible functionalities across the application and middleware layers. First, we provide a solution to automatically generate cross-layer parsers and composers that abstract network messages into a uniform representation independent of the middleware used. Second, these generated parsers and composers are integrated within a mediation framework to support the deployment of the mediators synthesised at the application layer. More specifically, the generated parser analyses the network messages received from one component and transforms them into a representation that can be understood by the application-level mediator. Then, the application-level mediator performs the necessary data conversion and behavioural coordination. Finally, the composer transforms the representation produced by the application-level mediator into network messages that can be sent to the other component. The resulting unified mediation framework reconciles the differences between software components from the application down to the middleware layers. We validate our approach through a case study in the area of conference management
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