Load mitigation for wind turbines by a passive aeroelastic device

This paper conducts a preliminary investigation of a novel passive concept for the mitigation of loads on wind turbines. The device, which can be implemented as a flap or a pitching blade tip, moves passively in response to blade vibrations, opposing them, thereby yielding an attenuation of loads. In comparison to active load mitigation devices, such as active flaps, this solution has the advantage of not requiring sensors nor actuators, resulting in a particularly simple implementation, with potential benefits in manufacturing and maintenance costs, as well as in reliability and availability.The paper first describes the novel passive device, here implemented by means of a flap, highlighting its main characteristics. A proof of concept of the new idea is then given by a simulation study conducted with the combination of a sectional model of the flap and an aeroservoelastic multibody model of the rest of the machine. Results, obtained for a 10. MW wind turbine, indicate the ability of the passive flap in attenuating blade vibrations in a significant frequency range, which in turn yield a reduced fatigue damage to the structure without noticeable effects in terms of power production and ultimate loads

Lithium and proton conducting gel-type membranes

We review the characteristics and the properties of various types of gel-type, ionically conducting membranes. We have mainly investigated two classes of membranes, one characterized by lithium ion transport and the other characterized by proton conductivity. We show that the former membranes are suitable to be used as separators in advanced lithium ion plastic batteries and that the latter show good promises to be considered as alternative, new separators in polymer electrolyte fuel cells. © 2003 Elsevier B.V. All rights reserved

Benign paroxysmal positional vertigo following whiplash injury: a myth or a reality?

Objective: The aim of the study was to evaluate the true incidence, diagnosis, and treatment of benign paroxysmal positional vertigo (BPPV) arising after whiplash injury and to distinguish this type of posttraumatic vertigo from other types of dizziness complained after trauma. Methods: This was a retrospective study comprising patients referred to our center after whiplash injury. The patients were evaluated with neurotologic examination including bedside and instrumental tests. A Dizziness Handicap Inventory evaluating the symptoms of patients was submitted before and after treatment and was evaluated. The BPPV patients were separately evaluated from those with cervicogenic vertigo, and a comparison between our data about idiopathic BPPV was done. Results: Eighteen patients of whiplash who had BPPV were evaluated. The mean age was 38.2 years. BPPV was the cause of vertigo in 33.9% of total whiplash patients. In 16 cases, the posterior semicircular canal was involved; the lateral semicircular canal was involved in 2 cases. The instrumental neurotologic assessment did not show any alteration of either vestibulospinal reflexes or dynamic ocular movements. Duration of symptoms before treatment ranged from 3 to 26 days. A total of 55.5% of patients had relief from their symptoms after first repositioning maneuver. The Dizziness Handicap Inventory score improved in all patients treated with repositioning maneuvers, but no difference emerged with idiopathic BPPV data. Conclusion: BPPV after whiplash injury could be unveiled with a simple bedside examination of peripheral vestibular system, and a treatment could be done in the same session. The diagnosis of posttraumatic BPPV is not different from the idiopathic form, but the treatment may require more maneuvers to achieve satisfactory results

Romano, Santi

Santi Romano was born in Palermo, Sicily on January 31, 1875. His origins had a notable impact on his legal training, as Palermo was the cradle of a host of renewed legal studies that changed once and for all the way of approaching public law in Italy. His teacher, Vittorio Emanuele Orlando, was both a leading statesman and an innovator of the notion and practice of public and administrative law. The young Romano contributed to a seminal collection of volumes, edited by Orlando, devoted to Italian administrative law, Primo trattato completo di diritto amministrativo italiano (First Complete Treatise on Italian Administrative Law), published between 1900 and 1915. The importance Orlando and his many collaborators attached to such a monumental scholarly enterprise should not go unnoticed: in his preface to the first volume, Orlando emphasized his and the other contributors’ conscious, and eventually successful, attempt at constructing an Italian school of public law. This collection of writings, he claimed, was the necessary counterpoint to the growing expansion of the state’s competences in the public realm. While in the past, Italian scholars had been heavily influenced by the French lawyers who had been working and mulling over the Code Napoléon and, subsequently, by the German pandectists, Orlando insisted that the specialization and evolution of the Italian state called for a full-fledged “homegrown” scholarly apparatus. After obtaining his degree at the University of Palermo, Romano wholeheartedly adhered to this ambitious project

Adaptive Algorithms for Batteryless LoRa-Based Sensors

Ambient energy-powered sensors are becoming increasingly crucial for the sustainability of the Internet-of-Things (IoT). In particular, batteryless sensors are a cost-effective solution that require no battery maintenance, last longer and have greater weatherproofing properties due to the lack of a battery access panel. In this work, we study adaptive transmission algorithms to improve the performance of batteryless IoT sensors based on the LoRa protocol. First, we characterize the device power consumption during sensor measurement and/or transmission events. Then, we consider different scenarios and dynamically tune the most critical network parameters, such as inter-packet transmission time, data redundancy and packet size, to optimize the operation of the device. We design appropriate capacity-based storage, considering a renewable energy source (e.g., photovoltaic panel), and we analyze the probability of energy failures by exploiting both theoretical models and real energy traces. The results can be used as feedback to re-design the device to have an appropriate amount energy storage and meet certain reliability constraints. Finally, a cost analysis is also provided for the energy characteristics of our system, taking into account the dimensioning of both the capacitor and solar panel