Search results for "SPEED"
showing 10 items of 876 documents
Evaluation of motorway reliability based on the identification of spot speed stochastic processes. The case of A22 motorway, Italy
2012
The evaluation of motorway reliability is a subject of great interest for researchers of traffic engineering. For easy recognizable reasons, this subject is very important in theoretical studies and for applications, e.g. evaluation of capacity and traffic control on motorway. In this paper the different conceptions of reliability in technical and scientific literature are compared with the following definition: reliability of traffic stream, for a time interval T, is “the conditioned probability that level of speed spot process does not decrease during T as far as the section in which limit density is reached, given that the level at instant zero is equal to the average speed corresponding…
Calibration of Speed-Density Relationships for Freeways in Aimsun
2014
The first application of a calibration methodology which uses speed-density relationships in the microsimulation calibration process is described in this article. Traffic patterns were implemented developing speed-density relationships for empirical and simulated data. For empirical relationships reference was made to traffic data observed at A22 Freeway (Italy). Aimsun microscopic traffic simulator software was then used to obtain analogous relationships for a test freeway segment under uncongested traffic conditions. Thus on field conditions were reproduced varying some calibration parameters until a good matching between field and simulation was achieved. The closeness between empirical …
L'Alta Velocità in Cina. Politiche, strategie, territori
2014
High Speed railways in China. Policies, strategies and territories. by Marc Guigon The history of High-Speed railways in China is not a linear one, traced in the course of a rigorous planning process. It has on the contrary experienced moments of rapid surge, only to be followed by periods of slower growth. Fervid action, decision-making and euphoria have been accompanied by scathing failures, against a background of corruption and complex relations with the foreign providers of fundamental technology. The ! nal result is noteworthy however, because China currently has the largest High-Speed railroad network in the world, with a very high level of customer satisfaction, though the cost has …
L'infrastruttura scomparsa. Il nuovo suolo della stazione Sagrera Alta Velocità a Barcellona
2014
The vanishing infrastructure. The new ground of the Sagrera High-Speed railway station in Barcelona The current railway station mega-project in Barcelona Sagrera highlights the link between the construction of the new High- Speed station and a vast linear park that will cover the existing railroad tracks. In the framework of one of the largest and most ambitious railway and urban redevelopment projects currently underway in all of Europe, this article focuses on the subordination of the Station to the park, which apart from being a mere issue of location (the station is literally under the park), can be reframed within a theoretical debate on the role of architecture in these truly signific…
LA CITTÁ DOPO IL PROGRESSO: LA STAZIONE DI STOCCARDA E L’AEROPORTO DI BERLINO
2014
The city post-progress: the station in Stuttgart and the airport in Berlin. by Florian Hertweck. In 2012 the Biennale di Venezia dedicated an entire room to the Hamburg Philharmonic. This was a tribute to the project by Herzog and De Meuron, but not for its splendid architecture, rather for the disaster represented by its construction. In a country which has built its identity around its faith in progress and growth, as much as its capacity for developing, on the national scale, a complex of technical, social and cultural infrastructures that is among the most competitive in the world, the inability to bring projects of this scope to term reveals a change in paradigm. In fact, the failure o…
STAZIONI DELL’ALTA VELOCITÁ IN GIAPPONE. TIPOLOGIA ARCHITETTONICA E URBANA DI UN MODELLO PRAGMATICO
2014
High-Speed railway stations in Japan. The architectural and urban typology of a pragmatic model. By Corinne Tiry-Ono The Japanese high-speed railway service was launched in 1964, during a time of rapid economic and demographic growth. It gave birth to a new, standardized generation of railway stations, and embodied the Tokaido Megalopolis. Originally centred on the capital city, its network now stretches across the entire country, seeking a better balance in terms of regional economic development and the revitalization of peripheral areas. Topographical constraints, natural risks and technical choices (elevated tracks, frequent tunnels, and speci! c rail gauge) led to a physically and techn…
Development of “Design of Experiments” for modelling direct expansion air-conditioning systems under variable cooling loads and faulty operating cond…
2019
Air conditioning systems are widely adopted in the building sector and are generally responsible for high energy consumption. Part of this consumption is related to the poor maintenance adopted by plant owner over time, which causes energy performance degradation. Typical faults, such as fouling or improper refrigerant charge have been shown to heavily impact on energy consumption of these systems. In order to support cost-effective maintenance schedule, Fault Detection and Diagnosis Technique are under investigation in the world. However, in order to devise a diagnostic method a preliminary modelling of air conditioning system is due. To this aim, a test procedure which requires the least …
STUDIO DI UN AMMORTIZZATORE ELETTROMAGNETICO A RECUPERO DI ENERGIA
2013
Questo lavoro ha come obiettivo principale lo studio teorico e con supporto di software F.E.M. di un dispositivo che consenta recupero energetico da una sospensione automobilistica. In sostituzione allo smorzatore viscoso, che dissipa l’energia cinetica del veicolo a seguito dell’attraversamento di strade sconnesse o ostacoli più marcati, si è usato uno smorzatore elettromagnetico che svolga le funzioni dello smorzatore viscoso consentendo un recupero di energia elettrica. Lo smorzatore elettromagnetico è di tipo a magneti permanenti e il suo funzionamento si basa sul fenomeno dell’induzione elettromagnetica. Il modello matematico descrive il funzionamento dello smorzatore, restituendo i va…
EXPERIMENTAL INVESTIGATIONS OF MINIMUM POWER CONSUMPTION OPTIMAL CONTROL FOR VARIABLE SPEED AMB ROTOR
2010
The purpose of this paper is to present a method for development of the optimal speed-dependent control matrix for a rotor supported on active magnetic bearings (AMBs) with the provision of minimum control power consumption over the operating speed range. The speed dependency of the optimal control matrix is the result of the dynamics of rotating machines. Most of published works on optimal control use a stationary optimal control matrix derived for the non-rotating system and thus neglecting the effect of gyroscopic phenomena. This paper employs the minimum energy consumption condition to derive the speed varying optimal control for rotating AMB rotor system. In the presented approach the …
CFD simulations of dense solid–liquid suspensions in baffled stirred tanks: Prediction of the minimum impeller speed for complete suspension
2012
Abstract In the literature on mechanically agitated solid–liquid systems, several methods are described to estimate the minimum impeller speed Njs at which all particles are suspended, but few studies have been devoted so far to their critical comparative assessment [67] . In the present paper, several alternative Njs prediction methods are applied to CFD results obtained for selected test cases covering a broad range of suspension conditions and impeller speeds. Results are compared with one another and with classic empirical correlations [88] . The aim of the work is to assess the adequacy of different methods for predicting Njs and, more generally, to contribute to a viable CFD-based str…