649 research outputs found

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    Art is a very personal statement. When viewing art I look for pieces to which I can relate and enjoy, whether they are realistic or abstract. When I create a piece of art it is my personal observations, experiences and spiritual connection to the piece that helps me create it. After many years of working in charcoal, chalk pastels and acrylics, mostly creating art centered around the female form, I decided to try sculpting in clay. I found the experience to be really challenging, but enjoyable. This piece is an attempt to bring many pieces of my life with my husband together in a single work of art. The serene face of the female like form seems to be reflecting on the items she holds which embody the desert of Arizona with its mountains and cactus tied to the sun and moon, which have been important in many places we have lived along with the water and boating. The form who sits in sand has almost snake like arms that hold the pieces of life together and, finally, on her back is the tattoo of a motorcycle. A vehicle that has been on this life journey from earliest days to the current time

    Rotors on Active Magnetic Bearings: Modeling and Control Techniques

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    In the last decades the deeper and more detailed understanding of rotating machinery dynamic behavior facilitated the study and the design of several devices aiming at friction reduction, vibration damping and control, rotational speed increase and mechanical design optimization. Among these devices a promising technology is represented by active magnetic actuators which found a great spread in rotordynamics and in high precision applications due to (a) the absence of all fatigue and tribology issues motivated by the absence of contact, (b) the small sensitivity to the operating conditions, (c) the wide possibility of tuning even during operation, (d) the predictability of the behavior. This technology can be classified as a typical mechatronic product due to its nature which involves mechanical, electrical and control aspects, merging them in a single system. The attractive potential of active magnetic suspensions motivated a considerable research effort for the past decade focused mostly on electrical actuation subsystem and control strategies. Examples of application areas are: (a) Turbomachinery, (b) Vibration isolation, (c) Machine tools and electric drives, (d) Energy storing flywheels, (e) Instruments in space and physics, (f) Non-contacting suspensions for micro-techniques, (g) Identification and test equipment in rotordynamics. This chapter illustrates the design, the modeling, the experimental tests and validation of all the subsystems of a rotors on a five-axes active magnetic suspension. The mechanical, electrical, electronic and control strategies aspects are explained with a mechatronic approach evaluating all the interactions between them. The main goals of the manuscript are: • Illustrate the design and the modeling phases of a five-axes active magnetic suspension; • Discuss the design steps and the practical implementation of a standard suspension control strategy; • Introduce an off-line technique of electrical centering of the actuators; • Illustrate the design steps and the practical implementation of an online rotor selfcentering control technique. The experimental test rig is a shaft (Weight: 5.3 kg. Length: 0.5 m) supported by two radial and one axial cylindrical active magnetic bearings and powered by an asynchronous high frequency electric motor. The chapter starts on an overview of the most common technologies used to support rotors with a deep analysis of their advantages and drawbacks with respect to active magnetic bearings. Furthermore a discussion on magnetic suspensions state of the art is carried out highlighting the research efforts directions and the goals reached in the last years. In the central sections, a detailed description of each subsystem is performed along with the modeling steps. In particular the rotor is modeled with a FE code while the actuators are considered in a linearized model. The last sections of the chapter are focused on the control strategies design and the experimental tests. An off-line technique of actuators electrical centering is explained and its advantages are described in the control design context. This strategy can be summarized as follows. Knowing that: a) each actuation axis is composed by two electromagnets; b) each electromagnet needs a current closed-loop control; c) the bandwidth of this control is depending on the mechanical airgap, then the technique allows to obtain the same value of the closed-loop bandwidth of the current control of both the electromagnets of the same actuation axis. This approach improves performance and gives more steadiness to the control behavior. The decentralized approach of the control strategy allowing the full suspensions on five axes is illustrated from the design steps to the practical implementation on the control unit. Furthermore a selfcentering technique is described and implemented on the experimental test rig: this technique uses a mobile notch filter synchronous with the rotational speed and allows the rotor to spin around its mass center. The actuators are not forced to counteract the unbalance excitation avoiding saturations. Finally, the experimental tests are carried out on the rotor to validate the suspension control, the off-line electrical centering and the selfcentering technique. The numerical and experimental results are superimposed and compared to prove the effectiveness of the modeling approach

    Experimental Investigations on Dopamine Transmission Can Provide Clues on the Mechanism of the Therapeutic Effect of Amphetamine and Methylphenidate in ADHD

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    The aim of this review is to compare the experimental evidence obtained from in vitro studies on the effect of amphetamine and methylphenidate on dopamine transmission with the results obtained in animal models of attention deficit hyperactivity disorder (ADHD). This comparison can extend the knowledge on the mechanism of action of the drugs used in the therapy of ADHD and provide insight into the etiology of ADHD. In particular, we considered the results obtained from in vitro methods, such as synaptosomes, cells in culture, and slices and from in vivo animal models of ADHD, such as spontaneous hypertensive rats (SHR) and the Naples high-excitability (NHE) rat lines. The different experimental approaches produce consonant results and suggest that in SHR rats, in contrast to Wistar Kyoto rats (WKY), amphetamine and depolarization by high K+ might release different pools of dopamine-containing vesicles. The pool depleted by amphetamine might represent dopamine that is stored in large dense core vesicles, whereas dopamine released by high K+ might be contained in small synaptic vesicles (SSV). The sustained dopamine transmission observed in the nucleus accumbens of SHR but not WKY rats can be supported by an elevated synthesis and release, which also might explain the stronger effect of methylphenidate on dopamine release in SHR but not in WKY rats. This hypothesis might enlighten the common therapeutic effect of these drugs, although their action takes place at different levels in catecholaminergic transmission

    Is There Convergence of Russia’s Regions? Exploring the Empirical Evidence: 1995 – 2010

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    This paper analyzes convergence in per capita gross regional product of Russia’s regions during the period 1995-2010, when regional data are available. Using a panel regression framework we find no evidence for beta-convergence. Instead we find divergence, which is, however, attenuated over time. Robustness checks that use regional real income instead of gross regional product confirm this outcome as do non-parametric estimates of convergence, namely estimates using Markov transition probability matrices and stochastic kernel plots of regional relative income. Decompositions of regional income and gross regional product also find no sigma-convergence of Russian regions. These decompositions point to the geographical concentration of extractive activities in the Urals and of business services and of the public administration in the Moscow area as the main culprit for this lack of convergence. They also establish that despite reforms to equalize provisions of public goods across Russia, the social services sector of the public administration, education and health still do not have the expected equalizing impact on regional income

    The development of Integrated Real Time Control to optimise storm water management for the combined sewer system of Rome

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    Increasing urbanisation and intensification of human activities are common trends all over the world. The higher portion of impermeable urban surfaces often leads to well known effects on storm water runoff and its polluting potential for receiving waters. Despite the variety of structural solutions and management practices proposed to mitigate the operational and environmental impact of urban runoff, their application on existing drainage systems can often be either ineffective at a metropolitan scale or unfeasible for a densely urbanised territory. Among all the proposed alternatives, the real time control (RTC) of drainage systems is proving more and more promising to dynamically regulate the system capacity in response to intense rainfall. The combined sewer network of Rome, historically built with high-capacity pipes to collect storm water from both urban and natural catchments, holds significant potential for RTC of online storage and combined sewer overflows, to optimise the global drainage capacity and reduce the impact of discharges on local river quality. To assess the real benefits, the potential limits and the feasibility of such a system for the city sewers, a pilot study has been conducted on a 3,000 hectare sub-catchment. It involved the development of a fast-response hydrodynamic simulation tool for the sewer network, the definition and evaluation of RTC strategies and the implementation of an environmental integrated telemetry system. As described here, the study has highlighted significant margins for the optimisation of the global network capacity without any major interventions on the physical assets, as well as some critical issues to solve for a fully operational RTC application

    A cloud robotics architecture for an emergency management and monitoring service in a smart cityenvironment

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    Cloud robotics is revolutionizing not only the robotics industry but also the ICT world, giving robots more storage and computing capacity, opening new scenarios that blend the physical to the digital world. In this vision new IT architectures are required to manage robots, retrieve data from them and create services to interact with users. In this paper a possible implementation of a cloud robotics architecture for the interaction between users and UAVs is described. Using the latter as monitoring agents, a service for fighting crime in urban environment is proposed, making one step forward towards the idea of smart cit

    The SWOT of Damocles: challenges in shaping inclusive place marketing audits

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    This paper extends existing research on inclusive place marketing by advancing methodological reflections on how to rework research instruments toward greater inclusivity. Our methodological reflections intend to encourage the dialogue between place marketing theory and practice, as well as reflections on the role that academic researchers take on while co-creating territorial development and promotion projects with a variety of non-academic stakeholders. This is done in the form of a self-reflective account of the multi-disciplinary tourism research team engaged in "RECOLOR" (Reviving and EnhanCing artwOrks and Landscapes Of the adRiatic). This is an INTERREG project funded by the European Commission that aims to enhance the tourist potential of secondary urban and natural resources in Croatia and Italy, with a view to generating sustainable development. Academics and consultants can replicate the research methods suggested in this paper when conducting participatory audits in other destinations

    Battery state of health estimation with improved generalization using parallel layer extreme learning machine

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    The online estimation of battery state of health (SOH) is crucial to ensure the reliability of the energy supply in electric and hybrid vehicles. An approach for enhancing the generalization of SOH estimation using a parallel layer extreme learning machine (PL-ELM) algorithm is analyzed in this paper. The deterministic and stable PL-ELM model is designed to overcome the drift problem that is associated with some conventional machine learning algorithms; hence, extending the application of a single SOH estimation model over a large set of batteries of the same type. The PL-ELM model was trained with selected features that characterize the SOH. These features are acquired as the discrete variation of indicator variables including voltage, state of charge (SOC), and energy releasable by the battery. The model training was performed with an experimental battery dataset collected at room temperature under a constant current load condition at discharge phases. Model validation was performed with a dataset of other batteries of the same type that were aged under a constant load condition. An optimum performance with low error variance was obtained from the model result. The root mean square error (RMSE) of the validated model varies from 0.064% to 0.473%, and the mean absolute error (MAE) error from 0.034% to 0.355% for the battery sets tested. On the basis of performance, the model was compared with a deterministic extreme learning machine (ELM) and an incremental capacity analysis (ICA)-based scheme from the literature. The algorithm was tested on a Texas F28379D microcontroller unit (MCU) board with an average execution speed of 93 µs in real time, and 0.9305% CPU occupation. These results suggest that the model is suitable for online applications

    Sediment Transport in Sewers: The Cesarina Combined Sewer Network

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    The polluting effects of storm water runoff on the receiving waterbodies represent an increasingly relevant problem in developing urban areas. In combined sewer pipes, transiting flood waves cause the alternation of sediment erosion and deposition of the solid material transported by the flow. Combined sewer deposit, mainly generated as an effect of such phenomena during the dry weather period between two rain events, is generally a mix of sand and highly polluting materials. Accumulation of sediments along a combined sewer network is often the cause of dysfunctions in the drainage system itself and negative impacts on the quality of receiving waters, due to the resuspension and overflow of pollutants. Both aspects have been investigated for the combined sewer of Rome thanks to an experimental catchment of about 2800 ha in the Cesarina – S. Basilio area. Based on the simulations conducted, structural solutions were proposed and evaluated, aimed at reducing the operational and environmental problems related to sewer sediment. The results show noticeable margins for the optimisation of the whole sewer system and for the reduction of its environmental impact
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