Simplified estimation of the train resistance parameters: full scale experimental tests and analysis

A CEN standard (EN 14067-4, 2005) describes the methodologies for the assessment of the running resistance of railway vehicles starting from full-scale test measurements. According to this standard, the speed dependent terms of the equation of Davis [1] have to be determined by means of coasting tests. In this paper, a new method to estimate the running resistance coefficients from a full-scale coasting test is proposed and compared with the two methods proposed in the CEN standard (the regression method and the speed history identification method). The main advantage of this new method is that it does not require the railway line characteristics to be known and it will be shown that the new method is able to evaluate the coefficients with an accuracy equivalent to that of the other methods considered

Numerical and Experimental Analysis of the Pressure Signature for different High-Speed Trains

This paper describes a procedure for the validation of numerical codes able to reproduce the pressures in tunnel due to the passage of trains. In the first step, the parameters of the numerical code are set by matching the train-tunnel pressure signature measured during a single-passage of different types of train within the tunnel and in the second step, without changing the parameters, the crossing of two trains is simulated. Within the paper, the methodology is applied to the numerical mono-dimensional code DB-Tunnel while the experimental data are those collected during an experimental research programme carried out in the tunnel La Fornace, on the Italian high-speed railway from Roma to Firenze. The accuracy of the numerical code estimation is evaluated in terms of the maximum pressure generated in the tunnel by the train passing/crossing because this is the key parameter, according to the TSI standard for railway infrastructures

Aerodynamic loads in open air of high speed trains: Analysis of experimental data

The homologation of high-speed trains is a demanding and expensive procedure. In particular, the evaluation of train slipstream according to the standard TSI, 2008 is divided in two different test programmes: one concerning the workers at the trackside and the other studying the passengers standing on the platform. This paper presents some slipstream measurements performed on three high speed trains and a comparison between them. The objective is to investigate the slipstream on the platform and relate it to the flow measured at the trackside at the same height with respect to the top of the rail. This topic is currently under revision by the commission in charge of the TSI standard. Interesting evidence concerning the improvements of the aerodynamic performance of new-generation trains are highlighted

Perturbation of Critical Prolines in Gloeobacter violaceus Ligand-gated Ion Channel (GLIC) Supports Conserved Gating Motions among Cys-loop Receptors.

Gloeobacter violaceus ligand-gated ion channel (GLIC) has served as a valuable structural and functional model for the eukaryotic Cys-loop receptor superfamily. In Cys-loop and other receptors, we have previously demonstrated the crucial roles played by several conserved prolines. Here we explore the role of prolines in the gating transitions of GLIC. As conventional substitutions at some positions resulted in nonfunctional proteins, we used in vivo non-canonical amino acid mutagenesis to determine the specific structural requirements at these sites. Receptors were expressed heterologously in Xenopus laevis oocytes, and whole-cell electrophysiology was used to monitor channel activity. Pro-119 in the Cys-loop, Pro-198 and Pro-203 in the M1 helix, and Pro-299 in the M4 helix were sensitive to substitution, and distinct roles in receptor activity were revealed for each. In the context of the available structural data for GLIC, the behaviors of Pro-119, Pro-203, and Pro-299 mutants are consistent with earlier proline mutagenesis work. However, the Pro-198 site displays a unique phenotype that gives evidence of the importance of the region surrounding this residue for the correct functioning of GLIC.This work was supported by grants from the NIH (NS 34407 to DAD) and the Wellcome Trust (WT 81925 to SCRL), and an NIH/NRSA training grant (GM07616 to MR).This is the final version of the article. It first appeared from American Society for Biochemistry and Molecular Biology via http://dx.doi.org/10.1074/jbc.M115.69437

Evolution of human IgH3 ' EC duplicated structures: both enhancers HS1,2 are polymorphic with variation of transcription factor's consensus sites

The enhancer complex regulatory region at the 3' of the immunoglobulin heavy cluster (IgH3'EC) is duplicated in apes along with four constant genes and the region is highly conserved throughout humans. Both human IgH3'ECs consist of three loci high sensitive (HS) to DNAse I with enhancer activity. It is thus possible that the presence of structural divergences between the two IgH3'ECs and of relative polymorphisms correspond to functional regulatory changes. To analyse the polymorphisms of these almost identical regions, it resulted mandatory to identify the presence of divergent sequences, in order to select distinctive primers for specific PCR genomic amplifications. To this aim, we first compared the two entire IgH3'ECs in silicio, utilising the updated GenBank (GB) contigs, then we analysed the two IgH3'ECs by cloning and sequencing amplicons from independent genomes. In silicio analysis showed that several inversions, deletions and short insertions had occurred after the duplication. We analysed in detail, by sequencing specific regions, the polymorphisms occurring in enhancer HS1,2-A (which lies in IgH3'EC-1, 3' to the C alpha-1 gene) and in enhancer HS1,2-B (which lies in IgH3'EC-2, 3' to C alpha-2). Polymorphisms are due to the repetition (occurring one to four times) of a 38-bp sequence present at the 3' of the core of enhancers HS1,2. The structure of both human HS1,2 enhancers has revealed not yet described polymorphic features due to the presence of variable spacer elements separating the 38-bp repetitions and to variable external elements bordering the repetition cluster. We found that one of the external elements gave rise to a divergent allele 3 in the two clusters. The frequency of the different alleles of the two loci varies in the Italian population and allele 3 of both loci are very rare. The analysis of the Callicebus moloch, Gorilla gorilla and Pan troglodytes HS1,2 enhancers showed the transformation from the ancestral structure with the 31- to the 17-by external element in hominids. The relevance of the polymorphisms in the HS1,2 enhancers is due to the variable number of binding sites for the transcription factors: NF-kappa B, CMYB, BSAP1/2, AP1/4, E47, MyoD and mu E5 and thus to the possible influence of these variations on switch, production of Ig and on maturation of B cells. (c) 2004 Elsevier B.V. All rights reserved

Analysis of 3 years of data from the gravitational wave detectors EXPLORER and NAUTILUS

We performed a search for short gravitational wave bursts using about 3 years of data of the resonant bar detectors Nautilus and Explorer. Two types of analysis were performed: a search for coincidences with a low background of accidentals (0.1 over the entire period), and the calculation of upper limits on the rate of gravitational wave bursts. Here we give a detailed account of the methodology and we report the results: a null search for coincident events and an upper limit that improves over all previous limits from resonant antennas, and is competitive, in the range h_rss ~1E-19, with limits from interferometric detectors. Some new methodological features are introduced that have proven successful in the upper limits evaluation.Comment: 12 pages, 12 figure