115 research outputs found

    Heat Flow Measurements on LHC Components

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    The refrigeration and liquefaction capacity necessary to operate at 1.9 K the 27 km long string of superconducting magnets of the LHC has been determined on the basis of heat load estimates, including static heat inleaks from ambient temperature, resistive heating and dynamic beam-induced heat loads. At all temperature levels, the static heat inleaks determine at least one third of the total heat loads in nominal operating conditions of the machine. Design validation of individual cryocomponents therefore requires a correct estimate of the heat inleaks they induce at all temperature levels, in order not to exceed the allocated heat budget. This paper illustrates the measurements of heat inleaks for several cold components of the future machine, including insulating supports, radiation shields, multi-layer insulation, instrumentation current leads. Distinct methods to determine the heat flow are chosen, depending on the expected heat loads, the temperature range spanned by the heat intercepts, and the working conditions of the component itself

    Association between amount of biventricular pacing and heart failure status measured by a multisensor implantable defibrillator algorithm

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    Background: Achieving a high biventricular pacing percentage (BiV%) is crucial for optimizing outcomes in cardiac resynchronization therapy (CRT). The HeartLogic index, a multiparametric heart failure (HF) risk score, incorporates implantable cardioverter-defibrillator (ICD)-measured variables and has demonstrated its predictive ability for impending HF decompensation. Objective: This study aimed to investigate the relationship between daily BiV% in CRT ICD patients and their HF status, assessed using the HeartLogic algorithm. Methods: The HeartLogic algorithm was activated in 306 patients across 26 centers, with a median follow-up of 26 months (25th–75th percentile: 15–37). Results: During the follow-up period, 619 HeartLogic alerts were recorded in 186 patients. Overall, daily values associated with the best clinical status (highest first heart sound, intrathoracic impedance, patient activity; lowest combined index, third heart sound, respiration rate, night heart rate) were associated with a BiV% exceeding 99%. We identified 455 instances of BiV% dropping below 98% after consistent pacing periods. Longer episodes of reduced BiV% (hazard ratio: 2.68; 95% CI: 1.02–9.72; P = .045) and lower BiV% (hazard ratio: 3.97; 95% CI: 1.74–9.06; P=.001) were linked to a higher risk of HeartLogic alerts. BiV% drops exceeding 7 days predicted alerts with 90% sensitivity (95% CI [74%–98%]) and 55% specificity (95% CI [51%–60%]), while BiV% ≤96% predicted alerts with 74% sensitivity (95% CI [55%–88%]) and 81% specificity (95% CI [77%–85%]). Conclusion: A clear correlation was observed between reduced daily BiV% and worsening clinical conditions, as indicated by the HeartLogic index. Importantly, even minor reductions in pacing percentage and duration were associated with an increased risk of HF alerts

    Characterization of the PTW 34031 ionization chamber (PMI) at RCNP with high energy neutrons ranging from 100 – 392 MeV

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    Radiation monitoring at high energy proton accelerators poses a considerable challenge due to the complexity of the encountered stray radiation fields. These environments comprise a wide variety of different particle types and span from fractions of electron-volts up to several terra electron-volts. As a consequence the use of Monte Carlo simulation programs like FLUKA is indispensable to obtain appropriate field-specific calibration factors. At many locations of the LHC a large contribution to the particle fluence is expected to originate from high-energy neutrons and thus, benchmark experiments with mono-energetic neutron beams are of high importance to verify the aforementioned detector response calculations. This paper summarizes the results of a series of benchmark experiments with quasi mono-energetic neutrons of 100, 140, 200, 250 and 392 MeV that have been carried out at RCNP - Osaka University, during several campaigns between 2006 and 2014

    La conservazione preventiva del patrimonio librario come possibile alternativa al restauro tradizionale

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    The present paper focuses on the close relation between library collections and their preservation environment, aiming, in particular, at highlighting the importance of promoting and sustaining the monitoring. The paper proposes some simple and ready-to-use technologies – smart monitoring – to prevent future damages
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