Optimal design of stationary supercapacitors storage devices for light electrical transportation systems

Recently a great interest has been paid in the relevant literature to the use of energy storage systems for the performance improvement of electrified light transit systems. In this context, the main targets are the increase of the energetic efficiency and the reduction of pantograph voltage drops. Therefore, it can be very interesting the determination of the optimal characteristics of a storage device for satisfying these objectives, both in stationary and onboard case. In this paper, this problem is approached for a sample case study, by showing that the optimal design of a stationary storage device can be regarded as a classical isoperimetric problem, whose solution is very attractive in order to determine also the optimal allocation of the storage device. For more complex configurations of the transit system, the methodology presented can be extended by solving a constrained optimization problem, which in a quite general manner is capable of matching all the assigned technical requirements. The reported simulations confirm the validity of the proposed design approach.     

Increasing the maximum strain and efficiency of bucky gel actuators by pyrrole oxidative polymerization on carbon nanotubes dispersed in an ionic liquid

Oxidative polymerization of pyrrole directly on preformed bucky gel slurry was carried out in order to combine the remarkable properties of ionic actuators based on carbon nanotubes and polypyrrole. Bimorph solid state ionic actuators were prepared with this novel hybrid material and compared with classical bucky gel actuators. A small amount of polypyrrole is sufficient to dramatically improve the overall actuator performance. The maximum strain is five times larger than the one of actuators prepared only with carbon nanotubes. Moreover, for the same applied charge, the strain generated increases up to twenty-five times.     

Condensation Heat Transfer and Pressure Gradient Inside Multiport Minichannels

Abstract

In this paper, the experimental heat transfer coefficients measured during condensation of R134a and R410A inside multiport minichannels are presented. The frictional pressure gradient was also measured during adiabatic two-phase flow. The need for experimental research on condensation inside multiport minichannels comes from the wide use of those channels in automotive air-conditioners. The perspective for the adoption of similar channels in the residential air conditioning applications also calls for experimental research on new high pressure refrigerants, such as R410A.

Experimental data are compared against models to show the accuracy of the models in the prediction of heat transfer coefficients and pressure drop inside minichannels.     

地区与全球之间

1986年,皮埃蒙特兰格区的布拉市(都灵以南50km)举行了一场在当今国际上影响深远的活动:记者卡尔洛·佩特里尼资助ArciGola协会抗议快餐在意大利的蔓延。3年之后,这一广为人知的运动发展成慢食运动。慢食协会兼顾美食与生态:基于其认识到美食与环境、文化、政治之间的根本联系(新美食学的概念),该组织从各领域推动饮食教育,维护食品供应的多样性,并且将可持续的生产者与他们所谓的"联合生产者"——那些了解食品来源和生产途径的受过教育的消费者——联系起来。慢食运动引入的美食学新视角旨在通过保护地区食品多样性以及农业传统来解决可持续性问题,如今,它可以依靠遍布世界150     

The influence of wind generation on power system reliability and the possible use of hydrogen storages

The aim of this study is to simulate the impact of non-programmable generation sources, in particular wind farms, on the reliability of an electric power system. A probabilistic model has been implemented, to evaluate the influence of wind generation on the amount of secondary/tertiary generating reserve, required in a hydro-thermoelectric system to maintain a certain level of reliability.     

Towards a Universal Method for the Stable and Clean Functionalization of Inert Perfluoropolymer Nanoparticles: Exploiting Photopolymerizable Amphiphilic Diacetylenes

Highly fluorinated materials are being widely investigated due to a number of peculiar properties, which are potentially useful for various applications, including use as lubricants, anti‐adhesive films, and substitutes for biological fluids for biomedical utilization. However, at present such potential is still poorly exploited. One of the major drawbacks that hampers the rapid development of nanoscale fluoro‐hybrid devices is the remarkable inertness of perfluoropolymeric materials that lack reactive functionalities, as they do not offer any functional groups that can be employed to covalently anchor organic molecules on their surface. In this paper, a convenient method for the stable biofunctionalization of strongly unreactive perfluoropolymer nanoparticles (PnPs) is reported. PnPs are easily coated with newly synthesized asymmetric diacetylenic monomer compounds (ADMs), thanks to PnP’s high propensity to interact with hydrophobic moieties. Once monomerically adsorbed onto PnPs, such suitably designed ADMs enable the formation of a robust polymeric shell around the perfluoroelastomer core via a clean UV‐promoted localized photopolymerization. Given the peculiar optical characteristics of PnPs, the coating of the particles can be monitored step by step using light scattering, which also allows estimation of the fraction of reacted monomers by competitive adsorption with smaller particles. The potential of this method for the biofunctionalization of PnPs is demonstrated with representative proteins and carbohydrates. Among them, the extension to avidin–biotin technology may broaden the scope and applicability of this strategy to potentially a large number of molecules of biomedical interest.     

Vision Based Position Control for MAVs Using One Single Circular Landmark

This paper presents a real-time vision based algorithm for 5 degrees-of-freedom pose estimation and set-point control for a Micro Aerial Vehicle (MAV). The camera is mounted on-board a quadrotor helicopter. Camera pose estimation is based on the appearance of two concentric circles which are used as landmark. We show that that by using a calibrated camera, conic sections, and the assumption that yaw is controlled independently, it is possible to determine the six degrees-of-freedom pose of the MAV. First we show how to detect the landmark in the image frame. Then we present a geometric approach for camera pose estimation from the elliptic appearance of a circle in perspective projection. Using this information we are able to determine the pose of the vehicle. Finally, given a set point in the image frame we are able to control the quadrotor such that the feature appears in the respective target position. The performance of the proposed method is presented through experimental results.     

Passage retrieval in legal texts

Legal texts usually comprise many kinds of texts, such as contracts, patents and treaties. These texts usually include a huge quantity of unstructured information written in natural language. Thanks to automatic analysis and Information Retrieval (IR) techniques, it is possible to filter out information that is not relevant and, therefore, to reduce the amount of documents that users need to browse to find the information they are looking for. In this paper we adapted the JIRS passage retrieval system to work with three kinds of legal texts: treaties, patents and contracts, studying the issues related with the processing of this kind of information. In particular, we studied how a passage retrieval system might be linked up to automated analysis based on logic and algebraic programming for the detection of conflicts in contracts. In our set-up, a contract is translated into formal clauses, which are analysed by means of a model checking tool; then, the passage retrieval system is used to extract conflicting sentences from the original contract text.     

Craze initiation in glassy polymers: Quantifying the influence of molecular orientation

A study has been made of crazing stress in oriented glassy polystyrene. The aim was to develop a methodology for prediction of crazing stress in glassy polymers with frozen-in molecular orientation. Oriented specimens of two grades of monodisperse polystyrene (PS) and one grade of polydisperse PS were produced by uniaxial melt-drawing and subsequent quenching of compression-moulded bars. Birefringence and crazing stress parallel to the draw direction (in the presence of diethylene glycol) were measured on miniature beam specimens cut from them. The crazing stress increased substantially with orientation, and the magnitude of the increase relaxed approximately on a timescale associated with the longest Rouse time. Specifically, a linear correlation was found, to within experimental scatter, between the increase in crazing stress and the orientation expressed in terms of frozen-in conformational stress, as predicted by the theory of Maestrini and Kramer [13]. The inverse gradient (constant β in the theory) was found to be 0.059 ± 0.002, when inferring the conformational stress from the measured birefringence. Crazing was found to be suppressed in favour of yielding in the most highly oriented specimens, and this could be explained in terms of the differing sensitivities of crazing and yield to molecular orientation.