Virtual Reference in Seville University Library: A shared experience.

Los servicios de referencia en las bibliotecas universitarias están lejos de desaparecer y las tecnologías, en este caso las de la web social, están facilitando e impulsando una cada vez más demandada referencia virtual, con aplicaciones al alcance de todos. LibraryH3lp es un software en código abierto, que ha permitido a la Biblioteca de la Universidad de Sevilla establecer un servicio de referencia virtual que comparten sus 19 bibliotecas de área, para atender preguntas generales o especializadas temáticas , así como las dudas sobre el uso de su catálogo Fama. Se presenta una primera valoración del servicio que se pondrá en completa explotación en este curso académico 2009‐2010. Palabras clave: Referencia virtual, Bibliotecas universitarias, software en cóigo abierto, LibraryH3lp, Biblioteca de la Universidad de SevillaReference services in academic libraries are far from dead and technologies of the social web are facilitating and encouraging an ever-increasing demand for virtual reference with applications available to everyone. The open source software LibraryH3lp has enabled the Library of the University of Seville to establish a virtual reference service shared among 19 libraries to answer common and specialized questions and explain the use of the Fama library catalog. We present a first assessment of the service that will go live in the academic year 2009-2010

Nonlinear Acoustic Spectroscopy and Frequency Sweep Ultrasonics: Case on Thermal Damage Assessment in Mortar

[EN] An exhaustive study on thermal damage of Portland cement-based materials is addressed. Damage carried out at different temperatures on concrete between 40 and 525 degrees C were assessed by means of microstructural, physical and nondestructive tests. Microstructural analysis (thermogravimetry and scanning electron microscopy) showed the principal changes of the Portland cement hydrated products for the different analysed temperatures. Compressive and flexural strengths remained constant or even increased at a low heating temperature range, while the mass loss increases. Dilatometry analysis revealed important information about deformation incompatibilities between the paste and the aggregate. These results have been correlated with nondestructive tests: nonlinear impact resonance acoustic spectroscopy (NIRAS) and ultrasonic measures. The dynamic modulus and ultrasonic pulse velocity have closely predicted the linear stiffness decay of the specimens. However, hysteretic parameter from NIRAS analysis exhibited a different trend from stiffness-related parameters, keeping constant until 250>degrees C and suffering a huge increasing for 400 and 525 degrees C. Ultrasonic attenuation computed with a broadband ultrasonic signal (chirp) revealed interesting information about scattering components inside the material, and is sensitive to interfacial transition zone between aggregate and paste in a large range of frequencies. The correlation between microstructural, mechanical and nondestructive techniques were carried out successfully. Nonlinear vibration and ultrasonic attenuation are non-conventional parameters that gave specific information about a complex damage process, such as a thermal attack in highly heterogeneous materials (e.g. Portland cement composites).This work has been supported by the Spanish Administration under Grants, BES2015-071469, under the ONDATEST coordinated project, BIA2014-55311-C2-1-P and BIA2014-55311-C2-2-P. Thanks are given to FEDER funds for co-funding.Genovés, V.; Carrión García, A.; Escobar, D.; Gosálbez Castillo, J.; Monzó Balbuena, JM.; Borrachero Rosado, MV.; Paya Bernabeu, JJ. (2019). Nonlinear Acoustic Spectroscopy and Frequency Sweep Ultrasonics: Case on Thermal Damage Assessment in Mortar. Journal of Nondestructive Evaluation. 38(3):1-14. https://doi.org/10.1007/s10921-019-0599-0S114383Aïtcin, P.C.: Binders for Durable and Sustainable Concrete. Taylor & Francis, London (2008)Ma, Q., Guo, R., Zhao, Z., Lin, Z., He, K.: Mechanical properties of concrete at high temperature—a review. Constr. Build. Mater. 93, 371 (2015)Schneider, U.: Concrete at high temperatures—a general review. Fire Saf. J. 13(1), 55 (1988)Cruz, C.R., Gilien, M.: Thermal expansion of Portland cement paste, mortar and concrete at high temperatures. Fire Mater. 4(2), 66 (1980)Jay, A.H.: The thermal expansion of quartz by X-ray measurements. Proc. R. Soc. Lond. 142(846), 237 (1933)Malhotra, V., Carino, N.: Handbook on Nondestructive Testing of Concrete. Civil Engineering. CRC Press, Boca Raton (2004)Van Den Abeele, K., Carmeliet, J., Ten Cate, J.A., Johnson, P.: Nonlinear elasticwave spectroscopy (NEWS) techniques to discern material damage. Part I: nonlinear wave modulation spectroscopy (NWMS). Res. Nondestruct. Eval. 12(1), 17 (2000)Johnson, P.A., Sutin, A.: Nonlinear elastic wave NDE I. Nonlinear resonant ultrasound spectroscopy and slow dynamics diagnostics. In: AIP Conference Proceedings (2005)Leśnicki, K.J., Kim, J.Y., Kurtis, K.E., Jacobs, L.J.: Characterization of ASR damage in concrete using nonlinear impact resonance acoustic spectroscopy technique. NDT & E Int. 44(8), 721 (2011)Park, S.J., Yim, H.J., Kwak, H.G.: Nonlinear resonance vibration method to estimate the damage level on heat-exposed concrete. Fire Saf. J. 69, 36 (2014)Dahlen, U., Ryden, N., Jakobsson, A.: Damage identification in concrete using impact non-linear reverberation spectroscopy. NDT & E Int. 75, 15 (2015)Genovés, V., Carrión, A., Gosálbez, J., Bosch, I., Borrachero, M.V., Payá, J.J.: Optimized ultrasonic attenuation measures for internal sulphate attack monitoring in Portland cement mortars (1)Genovés, V., Gosálbez, J., Carrión, A., Miralles, R., Payá, J.: Optimized ultrasonic attenuation measures for non-homogeneous materials. Ultrasonics 65, 345 (2016)Philippidis, T.P., Aggelis, D.G.: Experimental study of wave dispersion and attenuation in concrete. Ultrasonics 43(7), 584 (2005)Molero, M., Segura, I., Aparicio, S., Hernández, M.G., Izquierdo, MaG: On the measurement of frequency-dependent ultrasonic attenuation in strongly heterogeneous materials. Ultrasonics 50(8), 824 (2010)Genovés, V., Vargas, F., Gosálbez, J., Carrión, A., Borrachero, M., Payá, J.: Ultrasonic and impact spectroscopy monitoring on internal sulphate attack of cement-based materials. Mater. Design 125(Suppl C), 46 (2017)Park, G.K., Yim, H.J.: Evaluation of fire-damaged concrete: an experimental analysis based on destructive and nondestructive methods. Int. J. Concr. Struct. Mater. 11(3), 447 (2017)Payan, C., Ulrich, T., Le Bas, P., Griffa, M., Schuetz, P., Remillieux, M., Saleh, T.: Probing material nonlinearity at various depths by time reversal mirrors. Appl. Phys. Lett. 104(14), 144102 (2014)Payan, C., Ulrich, T.J., Le Bas, P.Y., Saleh, T., Guimaraes, M.: Quantitative linear and nonlinear resonance inspection techniques and analysis for material characterization: application to concrete thermal damage. J. Acoust. Soc. Am. 136(2), 537 (2014)Payan, C., Garnier, V., Moysan, J., Johnson, P.: Applying nonlinear resonant ultrasound spectroscopy to improving thermal damage assessment in concrete. J. Acoust. Soc. Am. 121(4), EL125 (2007)Yim, H.J., Kim, J.H., Park, S.J., Kwak, H.G.: Characterization of thermally damaged concrete using a nonlinear ultrasonic method. Cem. Concr. Res. 42(11), 1438 (2012)Borrachero, M.V., Payá, J., Bonilla, M., Monzó, J.: The use of thermogravimetric analysis technique for the characterization of construction materials. J. Therm. Anal. Calorim. 91, 503–509 (2008)Genovés, V., Soriano, L., Borrachero, M., Eiras, J., Payá, J.: Preliminary study on short-term sulphate attack evaluation by non-linear impact resonance acoustic spectroscopy technique. Constr. Build. Mater. 78, 295 (2015)Krautkrämer, J., Krautkrämer, H.: Ultrasonic Testing of Materials. Springer, New York (1983)Gaydecki, P.A., Burdekin, F.M., Damaj, W., John, D.G.: The propagation and attenuation of medium-frequency ultrasonic waves in concrete: a signal analytical approach. Meas. Sci. Technol. 3(1), 126 (1992

ATLAS TileCal read-out driver system production and initial performance results

8 pages, 9 figures.-- ISI Article Identifier: 000251744500005The ATLAS Hadronic Tile Calorimeter detector (TileCal) is an iron-scintillating tiles sampling calorimeter designed to operate at the Large Hadron Collider accelerator at CERN. The central element of the back-end system of the TileCal detector is a 9U VME Read-Out Driver (ROD) board. The operation of the TileCal calorimeter requires a total of 32 ROD boards. This paper summarizes the tests performed during the ROD production and the results obtained. Data processing is performed in the ROD by digital signal processors, whose operation is based on the use of online algorithms such as the optimal filtering algorithm for the signal amplitude, pedestal and time reconstruction and the online Muon tagging algorithm which identifies low transverse momentum muons. The initial performance of both algorithms run during commissioning is also presented in this paper.This work was supported by the Spanish Technology and Science Commission under project FPA2003-09220-C02-02.Peer reviewe

Algorithms for the ROD DSP of the ATLAS hadronic Tile Calorimeter

10 pages, 10 figures.-- ISI Article Identifier: 000253651100003.Final full-text version available at: http://ific.uv.es/tical/doc/2007_02_12_JINST_2_T02001.pdfIn this paper we present the performance of two algorithms currently running in the Tile Calorimeter Read-Out Driver boards for the commissioning of ATLAS. The first algorithm presented is the so called Optimal Filtering. It reconstructs the deposited energy in the Tile Calorimeter and the arrival time of the data. The second algorithm is the MTag which tags low transverse momentum muons that may escape the ATLAS muon spectrometer first level trigger.Comparisons between online (inside the Read-Out Drivers) and offline implementations are done with an agreement around 99% for the reconstruction of the amplitude using the Optimal Filtering algorithm and a coincidende of 93% between the offline and online tagged muons for the MTag algorithm. The processing time is measured for both algorithms running together with a resulting time of 59.2 μs which, although above the 10 μs of the first level trigger, it fulfills the requirements of the commissioning trigger (~ 1 Hz). We expect further optimizations of the algorithms which will reduce their processing time below 10 μs.The authors acknowledge the help of Oleg Solovyanov, Giulio Usai, Sasha Solodkov, Tomas Davidek and the whole TileCal community.Peer reviewe

Search for WZ resonances in the fully leptonic channel using pp collisions at s=8 TeV with the ATLAS detector

A search for resonant WZ production in the ℓνℓ'ℓ' (ℓ,ℓ'=e,μ) decay channel using 20.3 fb-1 of s=8TeV pp collision data collected by the ATLAS experiment at LHC is presented. No significant deviation from the Standard Model prediction is observed and upper limits on the production cross sections of WZ resonances from an extended gauge model W' and from a simplified model of heavy vector triplets are derived. A corresponding observed (expected) lower mass limit of 1.52 (1.49) TeV is derived for the W' at the 95% confidence level.Peer Reviewe

Search for vector-boson resonances decaying to a top quark and bottom quark in the lepton plus jets final state in pp collisions at s=13 TeV with the ATLAS detector

A search for new charged massive gauge bosons, W, is performed with the ATLAS detector at the LHC. Data were collected in proton–proton collisions at a center-of-mass energy of s=13 TeV and correspond to an integrated luminosity of 36.1 fb. This analysis searches for W bosons in the W→tb¯ decay channel in final states with an electron or muon plus jets. The search covers resonance masses between 0.5 and 5.0 TeV and considers right-handed W bosons. No significant deviation from the Standard Model (SM) expectation is observed and upper limits are set on the W→tb¯ cross section times branching ratio and the W boson effective couplings as a function of the W boson mass. For right-handed W bosons with coupling to the SM particles equal to the SM weak coupling constant, masses below 3.15 TeV are excluded at the 95% confidence level. This search is also combined with a previously published ATLAS result for W→tb¯ in the fully hadronic final state. Using the combined searches, right-handed W bosons with masses below 3.25 TeV are excluded at the 95% confidence level.Peer Reviewe

Search for heavy particles decaying into a top-quark pair in the fully hadronic final state in pp collisions at s =13 TeV with the ATLAS detector

A search for new particles decaying into a pair of top quarks is performed using proton-proton collision data recorded with the ATLAS detector at the Large Hadron Collider at a center-of-mass energy of s=13 TeV corresponding to an integrated luminosity of 36.1 fb-1. Events consistent with top-quark pair production and the fully hadronic decay mode of the top quarks are selected by requiring multiple high transverse momentum jets including those containing b-hadrons. Two analysis techniques, exploiting dedicated top-quark pair reconstruction in different kinematic regimes, are used to optimize the search sensitivity to new hypothetical particles over a wide mass range. The invariant mass distribution of the two reconstructed top-quark candidates is examined for resonant production of new particles with various spins and decay widths. No significant deviation from the Standard Model prediction is observed and limits are set on the production cross-section times branching fraction for new hypothetical Z′ bosons, dark-matter mediators, Kaluza-Klein gravitons and Kaluza-Klein gluons. By comparing with the predicted production cross sections, the Z′ boson in the topcolor-assisted-technicolor model is excluded for masses up to 3.1-3.6 TeV, the dark-matter mediators in a simplified framework are excluded in the mass ranges from 0.8 to 0.9 TeV and from 2.0 to 2.2 TeV, and the Kaluza-Klein gluon is excluded for masses up to 3.4 TeV, depending on the decay widths of the particles.Peer Reviewe

Search for pairs of highly collimated photon-jets in pp collisions at s =13 TeV with the ATLAS detector

Results of a search for the pair production of photon-jets - collimated groupings of photons - in the ATLAS detector at the Large Hadron Collider are reported. Highly collimated photon-jets can arise from the decay of new, highly boosted particles that can decay to multiple photons collimated enough to be identified in the electromagnetic calorimeter as a single, photonlike energy cluster. Data from proton-proton collisions at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 36.7 fb-1, were collected in 2015 and 2016. Candidate photon-jet pair production events are selected from those containing two reconstructed photons using a set of identification criteria much less stringent than that typically used for the selection of photons, with additional criteria applied to provide improved sensitivity to photon-jets. Narrow excesses in the reconstructed diphoton mass spectra are searched for. The observed mass spectra are consistent with the Standard Model background expectation. The results are interpreted in the context of a model containing a new, high-mass scalar particle with narrow width, X, that decays into pairs of photon-jets via new, light particles, a. Upper limits are placed on the cross section times the product of branching ratios σ×B(X→aa)×B(a→γγ)2 for 200 GeV<mX<2 TeV and for ranges of ma from a lower mass of 100 MeV up to between 2 and 10 GeV, depending upon mX. Upper limits are also placed on σ×B(X→aa)×B(a→3π0)2 for the same range of mX and for ranges of ma from a lower mass of 500 MeV up to between 2 and 10 GeV.Peer Reviewe

Search for tt¯ resonances in fully hadronic final states in pp collisions at √s = 13 TeV with the ATLAS detector

This paper presents a search for new heavy particles decaying into a pair of top quarks using 139 fb of proton-proton collision data recorded at a centre-of-mass energy of s = 13 TeV with the ATLAS detector at the Large Hadron Collider. The search is performed using events consistent with pair production of high-transverse-momentum top quarks and their subsequent decays into the fully hadronic final states. The analysis is optimized for resonances decaying into a tt¯ pair with mass above 1.4 TeV, exploiting a dedicated multivariate technique with jet substructure to identify hadronically decaying top quarks using large-radius jets and evaluating the background expectation from data. No significant deviation from the background prediction is observed. Limits are set on the production cross-section times branching fraction for the new Z′ boson in a topcolor-assisted-technicolor model. The Z′ boson masses below 3.9 and 4.7 TeV are excluded at 95% confidence level for the decay widths of 1% and 3%, respectively. [Figure not available: see fulltext.