1,721,075 research outputs found
Effect analysis of payload variation on energy consumption of a hydrogen powered light urban train
No full textIn this study a light hybrid rail train hydrogen powered is considered and the influence of the payload factor variation on traction energy consumption is investigated. For this purpose, a parametric software has been developed to simulate the train running over a railway path by varying the payload factor. As simulated system, an existing non-electrified single-track line has been taken into consideration and the traction energy requirement has been evaluated as function of the pay load factor. The specific fuel consumptions of a similar Diesel train have been compared under the same operating conditions. The results highlight that a significant fuel saving to be achieved
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
CITY BUS POWERED BY HYDROGEN FUEL CELL AND FLYWHEEL ENERGY STORAGE SYSTEM
No full textThis paper presents the design and application of
hybrid power train for city bus with zero greenhouse emissions
and high work efficiency. The vehicle system configuration is
based on two separately electric driven wheels powered by an
hybrid unit composed by a hydrogen fuel cell and flywheel
energy storage system. Numerical models were built to simulate
the powertrain components and to downsize the fuel cell power
satisfying the transient loads by the flywheel energy storage
device. A simulation of the city bus (15 passengers of carrying
capacity) was run over the European urban standard drive cycle
in order to size the powertrain components. Finally the hydrogen
production by water electrolysis was considered and consumption and CO2 emission per bus were estimated
High-Resolution tandem Farby-Perot interferometer for Ultra-Violet Brillouin scattering measurements
No full textModeling, Analysis and Implementation of an Urban Electric Light-Rail Train Hydrogen Powered
Full text linkA novel hydrogen power configuration of a Light Hybrid Electric (LHE) rail train able to operate along sub-urban non-electrified rail lines is proposed and analysed in the paper. The electric motors of the emission-free LHE rail train are fed by a hybrid power unit consisting of hydrogen fuel cell stacks and a set of high-speed kinetic energy storage systems. A control strategy of the power-train components has been developed to manage power flows in order to reduce the fuel consumption. This advanced and environment friendly hybrid propulsion system offers the opportunity to increase the power-train efficiency so that the fuel consumption is minimised. Simulator software of the proposed HLE rail train has been implemented in order to design the power-train components and compute train performance. A rail transport service is considered and a round trip journey of the LHE rail train is simulated over an existing re-designed not electrified single track line in the sub-urban area of L’Aquila city (Italy). Furthermore, the specific fuel consumption comparative analysis between the hydrogen rail train and a diesel one running over the selected path at the same operating conditions has been performed and the results are discussed in terms of CO2 emissions too. The results show that the proposed LHE rail train is technically suitable and advantage to operate in urban environmen
Multipolar laminated electromagnet for low-field magnetic resonance imaging and electron paramagnetic resonance imaging
No full textA cylindrical 16-pole electromagnet (EM) for electron paramagnetic resonance imaging (EPRI) and low-field magnetic
resonance imaging (MRI) has been designed by means
of two-dimensional and three-dimensional (3-D) finite element analysis (FEA). The use of an automatic procedure that combines FEA with a minimization routine allowed the optimization of the
design, in order to improve the homogeneity along the axis of the EM.
A prototype has been built by using electrical steel sheets
that were cut by laser; this solution reduced significantly the manufacturing cost.
The EM operates with a maximum flux density, in the bore, of
0.08 T and has a homogeneity along the axis of about 40 parts per million (ppm) in a spherical region 10 cm in diameter. It generates
the main field and two of the three field gradients required in the 3-D image reconstruction. Good agreement was found between
the results of simulation and the measured values
High-performance low-cost Hall probe measuring head
No full textAn electronic circuit is described that allows the use of an inexpensive Hall probe as a high-performance magnetic-field sensor. The circuit contains a high-precision voltage reference, a proportional control thermostat, a 16 bit serial analog-to-digital converter, and a digital control subsystem integrated into a single programmable logic device. The precision of the probe is of about 4 μT. © 1997 American Institute of Physics
Superconducting Sheets for Train Support and Traction : Finite Element Analysis
No full textThis paper presents a particular application of superconducting for magnetic levitation that uses the "Meissner effect".
The study has been performed by a two-dimensional Finite Element (FE) model made up of more superconducting material sheets placed in the proximity of a linear stator.
The forces on the sheets have been calculated by means of non-linear magnetostatic analysis with the "method of virtual works".
The parametric model has allowed to carry out systematic analysis that is a preliminary step to understand the phenomenon.
The intensity of pressures, both levitation and traction, are widely compatible with transportation applications
- …
