887 research outputs found
3D arrayed microwave tomographic system for medical imaging
In this paper, a combined tomographic imaging system comprising the rotation of a multiplexed linear antenna array around the object under test is designed. With this system a cylindrical sampling is obtained, allowing to scan realistic phantoms without important restrictions on its shape. This, combined with the non-application specific 3D ultrawide band (UWB) Hybrid Focusing reconstruction algorithm, allows to use this system in a wide range of applications. The design of a multiplexed array of UWB antennas for medical applications entails significant challenges including a large impedance bandwidth, small size and low coupling between elements, which will be treated in this paper.Peer ReviewedPostprint (published version
ElaboraciĂł d'una guia sobre aprenentatge cooperatiu a la Universitat de Girona
Lâany 2009, lâInstitut de CiĂšncies de lâEducaciĂł Josep Pallach de la Universitat
de Girona va impulsar la creaciĂł de diverses Xarxes dâInnovaciĂł Docent
(XID). Aquestes xarxes agrupen professors de disciplines diverses que volen
compartir experiĂšncies relatives a la millora docent. Una dâaquestes xarxes
Ă©s la relativa a lâAprenentatge Cooperatiu (XIDAC). Es compon de vuit professors
que utilitzen aquest mĂštode dâaprenentatge a la seva docĂšncia. Un
dels seus objectius Ă©s produir una guia o petit manual sobre aprenentatge
cooperatiu (AC) a la UdG. Es tracta dâorientar els professors que vulguin posar-
lo en prĂ ctica, o que ja ho estiguin fent i necessitin un material de suport.
A la present comunicaciĂł es descriu el procĂ©s dâelaboraciĂł dâaquesta guia.
En primer lloc, sâexposen caracterĂstiques de la UdG que poden determinarne
en algun sentit el perfil i continguts. Després, es resumeixen els resultats
dâentrevistes amb professors que apliquen lâAC tot i no pertĂ nyer a la Xarxa.
A continuaciĂł, es resumeixen els resultats dâuna enquesta elaborada al professorat
de la UdG (actualment estĂ en fase de resposta). Amb posterioritat,
es fa una presentaciĂł general de la futura guia i es descriu breument un
exemple de fitxa dâactivitat dâAC. Finalment, es fa referĂšncia al procĂ©s de
debat obert de part dâaquests continguts a travĂ©s dâuna pĂ gina web, per tal
de recollir punts de vista externs i millorar la proposta.Peer Reviewe
Review Paper on Road Vehicle Vibration Simulation for Packaging Testing Purposes
Inefficient packaging constitutes a global problem that costs hundreds of billions of dollars, not to mention the additional environmental impacts. An insufficient level of packaging increases the occurrence of product damage, while an excessive level increases the packages' weight and volume, thereby increasing distribution cost. This problem is well known, and for many years, engineers have tried to optimize packaging to protect products from transport hazards for minimum cost. Road vehicle shocks and vibrations, which is one of the primary causes of damage, need to be accurately simulated to achieve optimized product protection.
Over the past 50âyears, road vehicle vibration physical simulation has progressed significantly from simple mechanical machines to sophisticated computer-driven shaking tables. There now exists a broad variety of different methods used for transport simulation. Each of them addresses different particularities of the road vehicle vibration. Because of the nature of the road and vehicles, different sources and processes are present in the vibration affecting freight. Those processes can be simplified as the vibration generated by the general road surface unevenness, road surface aberrations (cracks, bumps, potholes, etc.) and the vehicle drivetrain system (wheels, drivetrain, engine, etc.).
A review of the transport vibration simulation methods is required to identify and critically evaluate the recent developments. This review begins with an overview of the standardized methods followed by the more advanced developments that focus on the different random processes of vehicle vibration by simulating non-Gaussian, non-stationary, transient and harmonic signals. As no ideal method exists yet, the review presented in this paper is a guide for further research and development on the topic
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Search for lepton-flavour-violating decays of Higgs-like bosons.
A search is presented for a Higgs-like boson with mass in the range 45 to 195 GeV/c2 decaying into a muon and a tau lepton. The dataset consists of proton-proton interactions at a centre-of-mass energy of 8 TeV , collected by the LHCb experiment, corresponding to an integrated luminosity of 2 fb-1 . The tau leptons are reconstructed in both leptonic and hadronic decay channels. An upper limit on the production cross-section multiplied by the branching fraction at 95% confidence level is set and ranges from 22 pb for a boson mass of 45 GeV/c2 to 4 pb for a mass of 195 GeV/c2
Observation of an Excited Bc+ State
Using pp collision data corresponding to an integrated luminosity of 8.5 fb-1 recorded by the LHCb experiment at center-of-mass energies of s=7, 8, and 13 TeV, the observation of an excited Bc+ state in the Bc+Ï+Ï- invariant-mass spectrum is reported. The observed peak has a mass of 6841.2±0.6(stat)±0.1(syst)±0.8(Bc+) MeV/c2, where the last uncertainty is due to the limited knowledge of the Bc+ mass. It is consistent with expectations of the Bcâ(2S31)+ state reconstructed without the low-energy photon from the Bcâ(1S31)+âBc+Îł decay following Bcâ(2S31)+âBcâ(1S31)+Ï+Ï-. A second state is seen with a global (local) statistical significance of 2.2Ï (3.2Ï) and a mass of 6872.1±1.3(stat)±0.1(syst)±0.8(Bc+) MeV/c2, and is consistent with the Bc(2S10)+ state. These mass measurements are the most precise to date
Study of charmonium production in b -hadron decays and first evidence for the decay Bs0
Using decays to Ï-meson pairs, the inclusive production of charmonium states in b-hadron decays is studied with pp collision data corresponding to an integrated luminosity of 3.0 fbâ1, collected by the LHCb experiment at centre-of-mass energies of 7 and 8 TeV. Denoting byBC ⥠B(b â C X) Ă B(C â ÏÏ) the inclusive branching fraction of a b hadron to a charmonium state C that decays into a pair of Ï mesons, ratios RC1C2 ⥠BC1 /BC2 are determined as RÏc0ηc(1S) = 0.147 ± 0.023 ± 0.011, RÏc1ηc(1S) =0.073 ± 0.016 ± 0.006, RÏc2ηc(1S) = 0.081 ± 0.013 ± 0.005,RÏc1 Ïc0 = 0.50 ± 0.11 ± 0.01, RÏc2 Ïc0 = 0.56 ± 0.10 ± 0.01and Rηc(2S)ηc(1S) = 0.040 ± 0.011 ± 0.004. Here and below the first uncertainties are statistical and the second systematic.Upper limits at 90% confidence level for the inclusive production of X(3872), X(3915) and Ïc2(2P) states are obtained as RX(3872)Ïc1 < 0.34, RX(3915)Ïc0 < 0.12 andRÏc2(2P)Ïc2 < 0.16. Differential cross-sections as a function of transverse momentum are measured for the ηc(1S) andÏc states. The branching fraction of the decay B0s â ÏÏÏ is measured for the first time, B(B0s â ÏÏÏ) = (2.15±0.54±0.28±0.21B)Ă10â6. Here the third uncertainty is due to the branching fraction of the decay B0s â ÏÏ, which is used for normalization. No evidence for intermediate resonances is seen. A preferentially transverse Ï polarization is observed.The measurements allow the determination of the ratio of the branching fractions for the ηc(1S) decays to ÏÏ and p p asB(ηc(1S)â ÏÏ)/B(ηc(1S)â p p) = 1.79 ± 0.14 ± 0.32
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