4,791 research outputs found
Components Qualification for a Possible use in the Mu2e Calorimeter Waveform Digitizers
The Mu2e experiment at Fermilab searches for the charged flavor violating
conversion of a muon into an electron in the Coulomb field of a nucleus. The
detector consists of a straw tube tracker and a CSI crystal electromagnetic
calorimeter, both housed in a superconducting solenoid. Both the front-end and
the digital electronics, located inside the cryostat, will be operated in
vacuum under a 1 T magnetic field, having to sustain the high flux of neutrons
and ionizing particles coming from the muons stopping target. These harsh
experimental conditions make the design of the calorimeter waveform digitizer
quite challenging. All the selected commercial devices must be tested
individually and qualified for radiation hardness and operation in high
magnetic field. At the moment the expected particles flux and spectra at the
digitizers location are not completely simulated and we are using initial rough
estimates to select the components for the first prototype. We are gaining
experience in the qualification procedures using the selected components but
the choice will be frozen only when dose and neutron flux simulations will be
completed. The experimental results of the first qualification campaign are
presented.Comment: TWEPP 2016 - Topical Workshop on Electronics for Particle Physics,
26-30 September 2016, Karlsruhe Institute of Technology (KIT
A Comparative Performance Analysis of GPS L1 C/A, L5 Acquisition and Tracking Stages under Polar and Equatorial Scintillations
This paper provides a comparative performance analysis of different acquisition and tracking methods of GPS L1 C/A and GPS L5 signals testing their robustness to the presence of scintillations in the propagation environment. The paper compares the different acquisition methods in terms of probabilities of detection/false alarm, peak-to-noise floor ratios for the acquired signal and execution time, assessing the performance loss in the presence of scintillations. Moreover, robust tracking architectures that are optimized to operate in a harsh ionospheric environment have been employed. The performance of the carrier tracking methods, namely, traditional Phase-Locked Loop (PLL) and Kalman filter based-PLL, have been compared in terms of the standard deviation of Doppler estimation, phase error, phase lock indicator (PLI) and phase jitter. The study is based on real GNSS signals affected by significant phase and amplitude scintillation effects, collected at the South African Antarctic research base (SANAE IV) and Brazilian Centro de Radioastronomia e Astrofisica Mackenzie (CRAAM) monitoring stations. Performance is assessed exploiting a fully software GNSS receiver which implements the different architectures. The comparative analysis allows to choose the best setting of the acquisition and tracking parameters, in order to allow the operation of signal acquisition and tracking at a required performance level under scintillation conditions
A Comparative Sensitivity Analysis of GPS Receivers
GNSS technologies are progressively becoming one
of the key elements in most of innovative wireless
applications. Most location-based services and
systems are in fact employing standalone GPS,
GPS+EGNOS (or WAAS), Assisted-GPS and
Differential GPS as core technologies and therefore
more and more companies have been integrating
GNSS receivers into their consumer products. By
considering the large number of available GPS
receivers on the market and the lack of standard
specifications on the performance, a general
evaluation of low cost GPS chipset is very
interesting. The present paper describes the
performance tests of a set of GPS receivers by
different manufacturers in different environmental
conditions (outdoor, light indoor, temporary
blockage of the signal). The results of the tests are
compared with the claimed performance reported on
the data sheets.
The comparative study on the performance is
performed according to different figures of merit:
acquisition sensitivity, Time To First Fix (TTFF)
and the accuracy.
Performance of the different receivers were tested
by means of a hardware platform and a software tool
called Sat-Surf and Sat-Surfer respectively
Analyticity of the SRB measure for a class of simple Anosov flows
We consider perturbations of the Hamiltonian flow associated with the
geodesic flow on a surface of constant negative curvature. We prove that, under
a small perturbation, not necessarely of Hamiltonian character, the SRB measure
associated to the flow exists and is analytic in the strength of the
perturbation. An explicit example of "thermostatted" dissipative dynamics is
constructed.Comment: 23 pages, corrected typo
Phenomenological interpolation of the inclusive J/psi cross section to proton-proton collisions at 2.76 TeV and 5.5 TeV
We present a study of the inclusive J/psi cross section at 2.76 TeV and 5.5
TeV. The energy dependence of the cross section, rapidity and transverse
momentum distributions are evaluated phenomenologically. Their knowledge is
crucial as a reference for the interpretation of A-A and p-A J/psi results at
the LHC. Our approach is the following: first, we estimate the energy evolution
of the pt-integrated J/psi cross section at mid-rapidity; then, we evaluate the
rapidity dependence; finally, we study the transverse momentum distribution
trend. Whenever possible, both theory driven (based on pQCD predictions) and
functional form (data driven fits) calculations are discussed. Our predictions
are compared with the recently obtained results by the ALICE collaboration in
pp collisions at 2.76 TeV.Comment: 23 pages, 19 figures, updated text+figures, added comparison to ALICE
measurements at 2.76Te
Speed and entropy of an interacting continuous time quantum walk
We present some dynamic and entropic considerations about the evolution of a
continuous time quantum walk implementing the clock of an autonomous machine.
On a simple model, we study in quite explicit terms the Lindblad evolution of
the clocked subsystem, relating the evolution of its entropy to the spreading
of the wave packet of the clock. We explore possible ways of reducing the
generation of entropy in the clocked subsystem, as it amounts to a deficit in
the probability of finding the target state of the computation. We are thus
lead to examine the benefits of abandoning some classical prejudice about how a
clocking mechanism should operate.Comment: 25 pages, 14 figure
Li1.4Al0.4Ge0.4Ti1.4(PO4)3 promising NASICON-structured glass-ceramic electrolyte for all-solid-state Li-based batteries: Unravelling the effect of diboron trioxide
Li-ion batteries (LIBs) are the ubiquitous technology to power portable electronics; however, for the next-generation of high-performing electrochemical energy storage systems for electric vehicles and smart grid facilities, breakthroughs are needed, particularly in the development of solid-state electrolytes, which may allow for enhanced energy density while enabling lithium metal anodes, combined with unrivalled safety and operative reliability. In this respect, here we present the successful synthesis of a glass-ceramic Li1.4Al0.4Ge0.4Ti1.4(PO4)3 NASICON-type solid-state electrolyte (SSE) through a melt-casting technique. Being grain boundaries crucial for the total ionic conductivity of SSEs, the effect of the addition of diboron trioxide (B2O3, 0.05 wt.%) to promote their liquefaction and restructuring is investigated, along with the effects on the resulting microstructures and ionic conductivities. By the thorough combination of structural-morphological and electrochemical techniques, we demonstrate that bulk materials show improved performance compared to their powder sintered counterpart, achieving remarkable ion mobility (> 0.1 mS cm–1 at –10 °C) and anodic oxidation stability (> 4.8 V vs Li+/Li). The addition of B2O3 positively affects the grain cohesion and growth, thus reducing the extension of the grain boundaries (and the related grain/grain interface resistance) and, therefore, increasing the overall ion mobility. In addition, B2O3 is seen to contrast the microcracks formation in the LAGTP system under study which, overall, shows very promising prospects as SSE for the next-generation of high-energy density, safe lithium-based batteries
Coupled plasma filtration and adsorption in septic shock: a multicentric experience
Introduction Recently extracorporeal removal of mediators and endotoxins improved haemodynamics, organ dysfunction and mortality in patients with abdominal sepsis [1]. Coupled plasma filtration and adsorption (CPFA), too, may improve haemodynamics, respiratory function and mortality through removal of proinfl ammatory mediator. The aim of this multicentric study is to evaluate the haemodynamic response and the respiratory function, and to evaluate the reduction of infl ammatory markers during CPFA.Methods Fifty-fi ve septic patients were enrolled in this study. Every patient
had four CPFA treatments (LINDA; Bellco-Mirandola, Italy) for 8 hours with
Qb = 200 ml/minute, Qultrafi ltration
= 30 ml/kg/hour and Qplasma = 20% of Q
b. At T0 (basal), T1 (after fi rst cycle), T2 (after second cycle), T3 (after third cycle)and T4 (after fourth cycle) we evaluated haemodynamic parameters,
norepinephrine dosage, PaO2/FiO
2 ratio, plasma IL-6, and procalcitonin (PCT). The ANOVA test was used to compare changes during times study. P <0.05 was considered statistically significant.
Results Patients enrolled in the study have been submitted to 256 CPFA
treatments for 2,650 hours. Table 1 presents the main results of the study.
IV quartile of IL-6 is shown in Table 1Conclusions In this large multicentric study, CPFA may improve
haemodynamic status and respiratory function. Plasma fi ltration and
adsorption of proinfl ammatory mediators may explain this improvement.
Larger randomized controlled trials are indicated to confi rm these data.
Reference
1.Cruz D, et al.: JAMA 2009, 23:2445-2452
The Atlantic blue crab Callinectes sapidus in southern European coastal waters: distribution, impact and prospective invasion management strategies
[EN] The native distribution of the blue crab Callinectes sapidus in the western Atlantic extends from Nova Scotia to Argentina. Introduced to Europe at the beginning of the 20th century, it is currently recorded almost ubiquitously in the Mediterranean and in the Black Sea. An overview of the occurrence, abundance, and ecological impact of the species in southern European waters is provided; additionally, we present a pragmatic assessment of its management scenarios, explicitly considering the dual nature of C sapidus as both an invasive species and a fishery resource. We emphasise that the ongoing expansion of C sapidus in the region may represent a stimulating challenge for the identification and implementation of future strategies in the management of invasive crustaceans. The impact of the invader could be converted into an enhancement of the services delivered by southern European coastal ecosystems, while mitigation costs could be transformed into profits for local populations. (C) 2017 Elsevier Ltd. All rights reserved.Funding from FUR 2013-2014 and 2014-2015 to G. M. is acknowledged. The European Fisheries Fund (FEP) Puglia Region (Italy) supported L. C. (CIP 04/OPI/010) as the scientific head of the MOLEVAR project (Pilot Project for the production of soft crabs from Carcinus aestuarii in Varano lagoon). The Portuguese Science Foundation (FCT) supported F. R. (SFRH/BPD/46761/2008) with a post-doctoral research grant from the Programa Operacional Potencial Humano/Fundo Social Europeu (POPH/FSE). F. R. and P. C. were also supported by the strategic MARE plan - Marine and Environmental Sciences Centre (UID/MAR/04292/2013).Mancinelli, G.; Chainho, P.; Cilenti, L.; Falco, S.; Kapiris, K.; Katselis, G.; Ribeiro, F. (2017). The Atlantic blue crab Callinectes sapidus in southern European coastal waters: distribution, impact and prospective invasion management strategies. Marine Pollution Bulletin. 119(1):5-11. https://doi.org/10.1016/j.marpolbul.2017.02.050S511119
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