299 research outputs found
Orizzonti del dopo Higgs. Un nuovo modelo di ricerca tecnologica
In this paper, some
considerations, born directly
from the field of the
technologist community engaged
in the research and development
of largest machine built by
mankind, the particle
accelerator Large Hadron
Collider (LHC) at CERN, are
presented. By this measuring
machine, the technology played
a crucial role for science,
bringing it to new horizons.
Conversely, at CERN, the key
concepts of advanced physics
have permeated the world of
technology. For the
technological research, a new
cooperative model of public
knowledge, free, meritocratic,
and supranational, is born. For
the technological researcher, a
new awareness arises, based on
the acceptance of his limits
and those of the produced technology. But above all, based on the enthusiasm for a new role of the
applied research, no longer dominated by profit, consumption or war, but for finally acting as free
knowledge engine
Metrological Characterization of an Improved DSP-Based On-line Integrator for Magnetic Measurements at CERN
An improved on-line version of the self-calibrating digital instrument for flux measurements on superconductive magnets for particle accelerators, prototyped at the European Organization for Nuclear Research (CERN) in cooperation with the University of Sannio, is proposed. The instrument acquires voltage arising from rotating coils transducers. Then, the samples are online integrated and suitably processed in order to achieve flux analysis time down to 2.0 ìs, with resolution of 50 ns. Details about hardware and firmware conception, on-line measurement principle, and preliminary results of metrological characterization of the prototype are provided
Noninvasive measurement of transdermal drug delivery by impedance spectroscopy
The effectiveness in transdermal delivery of skin permeation strategies (e.g., chemical enhancers, vesicular carrier systems, sonophoresis, iontophoresis, and electroporation) is poorly investigated outside of laboratory. In therapeutic application, the lack of recognized techniques for measuring the actually-released drug affects the scientific concept itself of dosage for topically- and transdermally-delivered drugs. Here we prove the suitability of impedance measurement for assessing the amount of drug penetrated into the skin after transdermal delivery. In particular, the measured amount of drug depends linearly on the impedance magnitude variation normalized to the pre-treated value. Three experimental campaigns, based on the electrical analysis of the biological tissue behavior due to the drug delivery, are reported: (i) laboratory emulation on eggplants, (ii) ex-vivo tests on pig ears, and finally (iii) in-vivo tests on human volunteers. Results point out that the amount of delivered drug can be assessed by reasonable metrological performance through a unique measurement of the impedance magnitude at one single frequency. In particular, in-vivo results point out sensitivity of 23 ml(-1), repeatability of 0.3%, non-linearity of 3.3%, and accuracy of 5.7%. Finally, the measurement resolution of 0.20 ml is compatible with clinical administration standards
Integrator Drift Compensation of Magnetic Flux Transducers by Feed-Forward Correction
Integrator drift is a problem strongly felt in different measurement fields, often detrimental even for short-term applications. An analytical method for modelling and feed-forward correcting drift in magnetic flux measurements was developed analytically and tested experimentally. A case study is reported on the proof of principle as a novel kind of quasi-DC field marker of the 5-ppm Nuclear Magnetic Resonance (NMR) transducer Metrolab PT2026, applied to the Extra Low ENergy Antiproton (ELENA) ring and the Proton Synchrotron Booster (PSB) at CERN. In some particle accelerators, such as in ELENA, the resulting feed-forward correction guarantees 1 ÎĽ T field stability over 120-s long magnetic cycle on a plateau of 50 mT, reducing by three orders of magnitude the field error caused by the integrator drift with respect to the state of the art
Surface Response-based Behavioral Modeling of Accurate Digitizers: a Case Study on a Fast Digital Integrator at CERN
A statistical approach to behavioral modeling for assessing dynamic metrological performance during the concept design of accurate digitizers is proposed. A surface-response approach based on statistical experiment design is exploited for avoiding unrealistic hypothesis of linearity, optimizing simulation, exploring operating conditions systematically, as well as verifying identification and validation uncertainty. An actual case study on the dynamic metrological characterization of a Fast Digital Integrator for high-performance magnetic measurements at the European Organization for Nuclear Research (CERN) is presented
Proof of Principle of an On-Line Digitizer with +18 ppm Repeatability and 1.2 ÎĽs Real-Time Delay for Power Converters Control Loop
The proof of principle of an on-line digitizer designed to be integrated into the digital
control loop of a high-voltage modulator for ultra-repeatable power converters is presented. The
presented selective analogue zoom allows digitizing with 18 ppm repeatability the voltage around
the nominal level (10V1 V) and, at the same time, the initial transients with relaxed performance.
In addition, in order not to jeopardize the digital control loop stability, the whole digitizing system has
to introduce a low real-time delay; this is assessed to be less than 1:2 s. Initially, the specifications
of the real-time control are presented and translated into data acquisition requirements. Then, the
main design choices of the digitizer are discussed and Pspice simulation results are reported to
validate the concept design. Finally, experimental results of a validation case study developed for
the power converter designed at ETH Zurich and University of Laval for the new linear particle
accelerator under study at CERN, the Compact LInear Collider CLIC, are reported and compared
with the simulation outcomes
Reducing parasitic resonances in particle accelerators components by broadband Higher Order Mode couplers
In particle accelerator components, parasitic resonances must be reduced
because they heat up the equipment and cause beam instabilities. In this paper,
a method for designing and characterizing Higher Order Mode (HOM) couplers for
reducing such resonances in a broad bandwidth is proposed. A case study is
considered for a specific component, called QuattroTank, showing geometrical
discontinuities and thus causing significant electro-magnetic resonances.
Results of numerical simulation and experimental emulation prove the capability
of the proposed method to reduce the peaks and the $Q-factor of the resonances
Smart Glasses for Visually Evoked Potential Applications: Characterisation of the Optical Output for Different Display Technologies
Off-the-shelf consumer-grade smart glasses are being increasingly used in extended reality and brain–computer interface applications that are based on the detection of visually evoked potentials from the user’s brain. The displays of these kinds of devices can be based on different technologies, which may affect the nature of the visual stimulus received by the user. This aspect has substantial impact in the field of applications based on wearable sensors and devices. We measured the optical output of three models of smart glasses with different display technologies using a photo-transducer in order to gain insight on their exploitability in brain–computer interface applications. The results suggest that preferring a particular model of smart glasses may strongly depend on the specific application requirements
Low-Density EEG Correction With Multivariate Decomposition and Subspace Reconstruction
A hybrid method is proposed for removing artifacts from electroencephalographic (EEG) signals. This relies on the integration of artifact subspace reconstruction (ASR) with multivariate empirical mode decomposition (EMD). The method can be applied when few EEG sensors are available, a condition in which existing techniques are not effective, and it was tested with two public datasets: 1) semisynthetic data and 2) experimental data with artifacts. One to four EEG sensors were taken into account, and the proposal was compared to both ASR and multivariate EMD (MEMD) alone. The proposed method efficiently removed muscular, ocular, or eye-blink artifacts on both semisynthetic and experimental data. Unexpectedly, the ASR alone also showed compatible performance on semisynthetic data. However, ASR did not work properly when experimental data were considered. Finally, MEMD was found less effective than both ASR and MEMD-ASR
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