Measuring track vertical stiffness through dynamic monitoring

[EN] This paper proposes a methodology for the evaluation of the track condition by means of the measurement of the track stiffness. This magnitude is calculated from vertical acceleration data measured at the axle box of trains during their normal operation. From the corresponding vertical acceleration spectra, the dominant vibration frequencies for each track stretch are identified and the combined stiffness is then determined. Then the stiffness without the contribution of the rail is calculated. The results obtained for a High Speed ballasted track in several track stretches are within the range 120-130 kN/mm, a result consistent with direct stiffness measurements taken during previous studies. Therefore, the proposed methodology may be used to obtain a first insight to the track condition by means of a continuous measurement of the track combined stiffness. This offers an alternative to traditional stationary stiffness measuring devices and might be a useful complement to dedicated continuous monitoring vehicles.Cano, MJ.; Martínez Fernández, P.; Insa Franco, R. (2016). Measuring track vertical stiffness through dynamic monitoring. Proceedings of the Institution of Civil Engineers - Transport. 169(1). doi:10.1680/jtran.14.00081S169

Analysis of the bearing capacity of unbound granular mixtures with rubber particles from scrap tyres when used as sub-ballast

[EN] Scrap tyres are a problematic waste material. As a method for recycling large quantities of rubber from scrap tyres, this paper analyses the use of unbound granular mixtures with varying percentages of rubber particles as sub-ballast in railway lines. Bearing capacity for such mixtures is studied in laboratory and field tests using static and dynamic plate load tests, as well as cyclic triaxial tests. It is found that adding rubber increases permanent and resilient strain and that none of the mixtures suffer plastic creep after 2.5 million cycles. Considering the usual bearing capacity requirements, the optimum rubber content is 2.5% (by weight). This percentage increases resistance to degradation while ensuring sufficient bearing capacity.Hidalgo Signes, C.; Martínez Fernández, P.; Garzón-Roca, J.; Insa Franco, R. (2016). Analysis of the bearing capacity of unbound granular mixtures with rubber particles from scrap tyres when used as sub-ballast. Materiales de Construcción. 66(324):1-15. doi:10.3989/mc.2016.11515S11566324Humphrey, D., & Blumenthal, M. (2010). The Use of Tire-Derived Aggregate in Road Construction Applications. Green Streets and Highways 2010. doi:10.1061/41148(389)25Wolfe, S. L., Humphrey, D. N., & Wetzel, E. A. (2004). Development of Tire Shred Underlayment to Reduce Groundborne Vibration from LRT Track. Geotechnical Engineering for Transportation Projects. doi:10.1061/40744(154)62Salgado, R., Yoon, S., & Siddiki, N. (2003). Construction of Tire Shreds Test Embankment. doi:10.5703/1288284313165Yoon, S., Prezzi, M., Siddiki, N. Z., & Kim, B. (2006). Construction of a test embankment using a sand–tire shred mixture as fill material. Waste Management, 26(9), 1033-1044. doi:10.1016/j.wasman.2005.10.009Sol-Sánchez, M., Thom, N. H., Moreno-Navarro, F., Rubio-Gámez, M. C., & Airey, G. D. (2015). A study into the use of crumb rubber in railway ballast. Construction and Building Materials, 75, 19-24. doi:10.1016/j.conbuildmat.2014.10.045Hidalgo Signes, C., Martínez Fernández, P., Medel Perallón, E., & Insa Franco, R. (2014). Characterisation of an unbound granular mixture with waste tyre rubber for subballast layers. Materials and Structures, 48(12), 3847-3861. doi:10.1617/s11527-014-0443-z8. PF-7 (2006) Pliego de Prescripciones Técnicas Generales de Materiales Ferroviarios PF-7: Subbalasto (General Technical Specifications for Railway Materials PF-7: Sub-ballast). Spanish Ministry of Public Works and Transport, Madrid. (In Spanish).10. Panadero, C.; Sanz, J.L. (2010) Análisis de las propiedades del sub-balasto: Contradicciones y procesos que afectan a su función (Analysis of sub-ballast properties: Contradictions and processes that affect their performance). Revista Ingeopres 196, 14–21. (In Spanish).12. Santiago, E.; García, J.L.; González, P. (2010) Comparación de diferentes métodos de control de compactación del subbalasto (Comparison of different sub-ballast compaction control methods). CEDEX Geotechnical Laboratory, Madrid. (In Spanish).Tompai, Z. (2008). Conversion between static and dynamic load bearing capacity moduli and introduction of dynamic target values. Periodica Polytechnica Civil Engineering, 52(2), 97. doi:10.3311/pp.ci.2008-2.0617. Melis, M. (2006). Terraplenes y Balasto en Alta Velocidad Ferroviaria (Embankment and ballast in high speed railways). Revista de Obras Públicas 3464, 7–36. (In Spanish).Werkmeister, S., Dawson, A. R., & Wellner, F. (2005). Permanent Deformation Behaviour of Granular Materials. Road Materials and Pavement Design, 6(1), 31-51. doi:10.1080/14680629.2005.9689998Cerni, G., Cardone, F., Virgili, A., & Camilli, S. (2012). Characterisation of permanent deformation behaviour of unbound granular materials under repeated triaxial loading. Construction and Building Materials, 28(1), 79-87. doi:10.1016/j.conbuildmat.2011.07.066Speir, R., & Witczak, M. (1996). Use of Shredded Rubber in Unbound Granular Flexible Pavement Layers. Transportation Research Record: Journal of the Transportation Research Board, 1547, 96-106. doi:10.3141/1547-1424. Santamarina, J.C.; Klein, K.A.; Fam, M.A. (2001) Soils and Waves. Particulate Materials. Behavior, Characterization and Process Monitoring. John Wiley & Sons Ltd., Baffins Lane, Chichester.25. Pe-a, M. (2003) Tramos de ensayo de vía en placa en la línea del corredor del Mediterráneo para su explotación a alta velocidad (Slab track test sites in the Mediterranean Corridor for high speed use). Revista de Obras Públicas 3431, 57–68. (In Spanish).Cecich, V., Gonzales, L., Hoisaeter, A., Williams, J., & Reddy, K. (1996). Use of Shredded Tires as Lightweight Backfill Material for Retaining Structures. Waste Management & Research, 14(5), 433-451. doi:10.1177/0734242x960140050

The ALICE experiment at the CERN LHC

ALICE (A Large Ion Collider Experiment) is a general-purpose, heavy-ion detector at the CERN LHC which focuses on QCD, the strong-interaction sector of the Standard Model. It is designed to address the physics of strongly interacting matter and the quark-gluon plasma at extreme values of energy density and temperature in nucleus-nucleus collisions. Besides running with Pb ions, the physics programme includes collisions with lighter ions, lower energy running and dedicated proton-nucleus runs. ALICE will also take data with proton beams at the top LHC energy to collect reference data for the heavy-ion programme and to address several QCD topics for which ALICE is complementary to the other LHC detectors. The ALICE detector has been built by a collaboration including currently over 1000 physicists and engineers from 105 Institutes in 30 countries. Its overall dimensions are 161626 m3 with a total weight of approximately 10 000 t. The experiment consists of 18 different detector systems each with its own specific technology choice and design constraints, driven both by the physics requirements and the experimental conditions expected at LHC. The most stringent design constraint is to cope with the extreme particle multiplicity anticipated in central Pb-Pb collisions. The different subsystems were optimized to provide high-momentum resolution as well as excellent Particle Identification (PID) over a broad range in momentum, up to the highest multiplicities predicted for LHC. This will allow for comprehensive studies of hadrons, electrons, muons, and photons produced in the collision of heavy nuclei. Most detector systems are scheduled to be installed and ready for data taking by mid-2008 when the LHC is scheduled to start operation, with the exception of parts of the Photon Spectrometer (PHOS), Transition Radiation Detector (TRD) and Electro Magnetic Calorimeter (EMCal). These detectors will be completed for the high-luminosity ion run expected in 2010. This paper describes in detail the detector components as installed for the first data taking in the summer of 2008

Influence du dephasage des sollicitations en fatigue biaxiale oligocyclique

SIGLECNRS AR 10630 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Clinical and molecular parameters associated to pneumonitis development in non-small-cell lung cancer patients receiving chemoimmunotherapy from NADIM trial

Altres ajuts: Fondo Europeo de Desarrollo Regional (FEDER); Bristol-Myers Squibb (BMS); Grupo Español de Cáncer de Pulmón (GECP); European Social Fund (ESF) i Comunidad de Madrid (PEJD-2019-PRE/BMD-17006, PEJ16/MED/AI-1972, PEJD-2018-PRE/SAL-8641).Background Pneumonitis (Pn) is one of the main immune-related adverse effects, having a special importance in lung cancer, since they share affected tissue. Despite its clinical relevance, Pn development remains an unpredictable treatment adverse effect, whose mechanisms are mainly unknown, being even more obscure when it is associated to chemoimmunotherapy. Methods In order to identify parameters associated to treatment related Pn, we analyzed clinical variables and molecular parameters from 46 patients with potentially resectable stage IIIA non-small-cell lung cancer treated with neoadjuvant chemoimmunotherapy included in the NADIM clinical trial (NCT03081689). Pn was defined as clinical or radiographic evidence of lung inflammation without alternative diagnoses, from treatment initiation to 180 days. Results Among 46 patients, 12 developed Pn (26.1%). Sex, age, smoking status, packs-year, histological subtype, clinical or pathological response, progression-free survival, overall survival and number of nivolumab cycles, were not associated to Pn development. Regarding molecular parameters at diagnosis, Pn development was not associated to programmed death ligand 1, TPS, T cell receptor repertoire parameters, or tumor mutational burden. However, patients who developed Pn had statistically significant lower blood median levels of platelet to monocyte ratio (p=0.012) and teratocarcinoma-derived growth factor 1 (p=0.013; area under the curve (AUC) 0.801), but higher median percentages of natural killers (NKs) (p=0.019; AUC 0.786), monocytes (p=0.017; AUC 0.791), MSP (p=0.006; AUC 0.838), PARN (p=0.017; AUC 0.790), and E-Cadherin (p=0.022; AUC 0.788). In addition, the immune scenario of Pn after neoadjuvant treatment involves: high levels of neutrophils and NK cells, but low levels of B and T cells in peripheral blood; increased clonality of intratumoral T cells; and elevated plasma levels of several growth factors (EGF, HGF, VEGF, ANG-1, PDGF, NGF, and NT4) and inflammatory cytokines (MIF, CCL16, neutrophil gelatinase-associated lipocalin, BMP-4, and u-PAR). Conclusions Although statistically underpowered, our results shed light on the possible mechanisms behind Pn development, involving innate and adaptative immunity, and open the possibility to predict patients at high risk. If confirmed, this may allow the personalization of both, the surveillance strategy and the therapeutic approaches to manage Pn in patients receiving chemoimmunotherapy

ALICE: Physics Performance Report, Volume II

ALICE is a general-purpose heavy-ion experiment designed to study the physics of strongly interacting matter and the quark\u2013gluon plasma in nucleus\u2013nucleus collisions at the LHC. It currently involves more than 900 physicists and senior engineers, from both the nuclear and high-energy physics sectors, from over 90 institutions in about 30 countries. The ALICE detector is designed to cope with the highest particle multiplicities above those anticipated for Pb\u2013Pb collisions (dNch/dy up to 8000) and it will be operational at the start-up of the LHC. In addition to heavy systems, the ALICE Collaboration will study collisions of lower-mass ions, which are a means of varying the energy density, and protons (both pp and pA), which primarily provide reference data for the nucleus\u2013nucleus collisions. In addition, the pp data will allow for a number of genuine pp physics studies. The detailed design of the different detector systems has been laid down in a number of Technical Design Reports issued between mid-1998 and the end of 2004. The experiment is currently under construction and will be ready for data taking with both proton and heavy-ion beams at the start-up of the LHC. Since the comprehensive information on detector and physics performance was last published in the ALICE Technical Proposal in 1996, the detector, as well as simulation, reconstruction and analysis software have undergone significant development. The Physics Performance Report (PPR) provides an updated and comprehensive summary of the performance of the various ALICE subsystems, including updates to the Technical Design Reports, as appropriate. The PPR is divided into two volumes. Volume I, published in 2004 (CERN/LHCC 2003-049, ALICE Collaboration 2004 J. Phys. G: Nucl. Part. Phys. 30 1517\u20131763), contains in four chapters a short theoretical overview and an extensive reference list concerning the physics topics of interest to ALICE, the experimental conditions at the LHC, a short summary and update of the subsystem designs, and a description of the offline framework and Monte Carlo event generators. The present volume, Volume II, contains the majority of the information relevant to the physics performance in proton\u2013proton, proton\u2013nucleus, and nucleus\u2013nucleus collisions. Following an introductory overview, Chapter 5 describes the combined detector performance and the event reconstruction procedures, based on detailed simulations of the individual subsystems. Chapter 6 describes the analysis and physics reach for a representative sample of physics observables, from global event characteristics to hard processes

LHCb

The LHCb detector is designed to study CP violation and other rare phenomena in decays of hadrons with heavy flavours, in particular $\rm B_s$ mesons. Interest in CP violation comes not only from elementary particle physics but also from cosmology, in order to explain the dominance of matter over antimatter observed in our universe, which could be regarded as the largest CP violation effect ever seen. The LHCb experiment will improve significantly results from earlier experiments both quantitatively and qualitatively, by exploiting the large number of different kinds of b hadrons produced at LHC. This is done by constructing a detector which has \begin{enumerate} \item Good trigger efficiencies for b-hadron final states with only hadrons, as well as those containing leptons. \item Capability of identifying kaons and pions in a momentum range of $\sim 1$ to above 100 GeV/$c$. \item Excellent decay time and mass resolution. \end{enumerate} The LHCb spectrometer shown in the figure consists of the following detector components: \begin{itemize} \item Beam Pipe\\ A 1.8 m-long section of the beam pipe around the interaction point has a large diameter of approximately 120 cm. This accommodates the vertex detector system with its retraction mechanics, and has a thin forward window made of aluminium over the full detector acceptance. This part is followed by two conical sections; the first is 1.5 m long with 25 mrad opening angle, and the second is 16 m long with 10 mrad opening angle. The entire first and most of the second section are made of beryllium in order to reduce the production of the secondary particles. \item Magnet\\ A dipole magnet with the normal conductive Al coil provides a high field integral of 4 Tm. The polarity of the field can be changed to reduce systematic errors in the CP-violation measurements that could result from a left-right asymmetry of the detector. \item Vertex Locator\\ A total of 21 stations made from two layers of silicon detector are used as a vertex detector system (VELO). Additional two stations with only one Si layer are dedicated to the detecting bunch crossings with more than one pp interaction as a part of Level-0 trigger. The closest distance between the active silicon area and the beam is 8 mm. The silicon detectors are placed in Roman pots with 300 $\mu$m thick aluminium windows, which act as a shield against RF pickup from the circulating beam bunches. In order to avoid collapse of the windows, a secondary vacuum is maintained inside the Roman pots. During the injection and acceleration, the Roman pot system will be moved away from the beam to avoid interference with the machine operation and accidental irradiation of the detectors. \item Tracking\\ The LHCb tracking system consists of four stations; one upstream of the magnet (TT) and three just behind the magnet (T1 to T3). No tracking device is positioned in the magnet and most of the tracks are reconstructed by combining the VELO and tracking system. The first station is made of silicon detectors. The stations behind the magnet are split into Inner Tracker (IT) and Outer Tracker (OT) systems due to the high particle density close to the beam pipe. The IT system is made of Si, and drift chambers based on straw technology are used for the OT system. \item Ring Imaging Cherenkov Detectors\\ The RICH system of the LHCb detector consists of two detectors with three different radiators in order to cover the required momentum range, 1-100 GeV/$c$ . The first detector uses aerogel and $\rm C_4 F_ {10}$ gas as radiators. The second detector, used for high momentum particles, is placed after the magnet and has $\rm C F_4$ gas as radiator. The Cherenkov light is detected with planes of Hybrid Photon Detectors (HPD's) placed outside the spectrometer acceptance. \item Calorimeters\\ The calorimeter system consists of a preshower detector followed by electromagnetic and hadronic calorimeters. It also serves as the initial part of the muon filter system. The cells of the Preshower detector are made up from 12 mm-thick lead plates sandwiched by square scintillators, 15 mm thick. For the electromagnetic part a Shashlik calorimeter is used since only modest energy resolution is required. The hadron calorimeter is based on a scintillating tile design similar to that developed for the ATLAS experiment. \item Muon System\\ The Muon system consists of tracking stations and absorber layers. The first tracking station is in front of the calorimeter system, which acts as the first absorber. Behind the calorimeter system, there are four tracking stations with Fe absorber walls in between. An additional Fe absorber is placed after the last tracking station against the muon background from the accelerator tunnel. Multi Wire Proportional Chambers are used everywhere except in the region close to the beam pipe of the first station where Triple-GEM chambers are used. \item Trigger\\ The LHCb trigger has two decision levels. Using custom made electronics, the first decision is made based on high transverse momentum hadrons or electrons found in the calorimeter system, or muons found in the muon system, at the bunch crossing rate of 40 MHz. All data from the detector are then read out at a rate of 1 MHz and sent to a CPU farm for further event reduction. For this purpose, all the detector information is available. With a rate of 2 kHz, events which include calibration data are stored for offline analysis. \end{itemize} Due to the large production cross section for b-$\rm \overline{ b}$ pairs (500~$\rm \mu b$) and efficient trigger, the LHCb experiment requires only a much lower luminosity ($2 \times 10^{32}$~$\rm cm^{-2} s^{-1}$) than the nominal LHC luminosity ($10^{34}$~$\rm cm^{-2}s^{-1}$) for its physics programme. The experiment therefore can reach its full physics potential from the beginning of LHC operation. The luminosity at the LHCb interaction point can be locally tuned so that the experiment is able to continue its physics programme when the machine reaches the nominal operating condition. \end{document

The LHCb Upgrade I

Abstract The LHCb upgrade represents a major change of the experiment. The detectors have been almost completely renewed to allow running at an instantaneous luminosity five times larger than that of the previous running periods. Readout of all detectors into an all-software trigger is central to the new design, facilitating the reconstruction of events at the maximum LHC interaction rate, and their selection in real time. The experiment's tracking system has been completely upgraded with a new pixel vertex detector, a silicon tracker upstream of the dipole magnet and three scintillating fibre tracking stations downstream of the magnet. The whole photon detection system of the RICH detectors has been renewed and the readout electronics of the calorimeter and muon systems have been fully overhauled. The first stage of the all-software trigger is implemented on a GPU farm. The output of the trigger provides a combination of totally reconstructed physics objects, such as tracks and vertices, ready for final analysis, and of entire events which need further offline reprocessing. This scheme required a complete revision of the computing model and rewriting of the experiment's software.</jats:p