Search

Wearable sensors are gaining in popularity because they enable outdoor experimental monitoring. This paper presents a cost-effective sensorised insole based on a mesh of tactile capacitive sensors. Each sensor's spatial resolution is about 4 taxels/cm^2 in order to have an accurate reconstruction of the contact pressure distribution. As a consequence, the insole provides information such as contact forces, moments, and center of pressure. To retrieve this information, a calibration technique that fuses measurements from a vacuum chamber and shoes equipped with force/torque sensors is proposed. The validation analysis shows that the best performance achieved a root mean square error (RMSE) of about 7 N for the contact forces and 2 N m for the contact moments when using the force/torque shoe data as ground truth. Thus, the insole may be an alternative to force/torque sensors for certain applications, with a considerably more cost-effective and less invasive hardware., 21 pages, 12 figures

In this study, a textile-based wearable strain sensor is fabricated to monitor human muscular activities with high sensitivity and large working range. To achieve electrical conductivity, a gum-like sticky polyvinyl acetate-co-vinyl laurate polymer (commercial name: VINNAPASS) is mixed with 50 wt % of carbon nanofiber (CNFs) using ethyl acetate as co-solvent. The VINNAPASS/CNFs-based ink is spray coated onto a stretchable polyethylene terephthalate fabric (commercial name: Lycra) and subsequently covered and stabilized with polydimethylsiloxane protective layer. Another reference sensor is also prepared using thermoplastic polyurethane (TPU) with equal concentration of CNFs. The strain sensor made with VINNAPASS demonstrated sheet resistance, maximum elongation at break, gauge factor (GF) and working range of 32.27 ± 1.60 Ω/□, 230 ± 6%, 67.12, >170% as compared to 48.44 ± 2.33 Ω/□, 122 ± 7%, 39.97 and ~100% for the sensor made with TPU, respectively. Moreover, the VINAPASS-based strain sensor displayed complete self-healing and >90% reversible electrical properties on damage, while the TPU-based sensor was not healable. Finally, the VINNAPASS-based sensor is used to monitor folding-unfolding of human finger and wrist as well as bicep muscle contraction and relaxation, and is envisioned for monitoring human muscular motions during physical activities and exercising.

We present the first results obtained with a prototype of the PET read-out electronics of the trimodal PET/MRI/EEG TRIMAGE scanner. The read-out is based on the 64-channel TRIROC ASIC and on an acquisition board that will control up to 12 ASICs. The output of each ASIC is processed in parallel and sent to a host system that in the final version will receive data from 18 acquisition boards. Blocks of 64 SiPMs are one-to-one coupled to a dual-layer staggered LYSO crystal matrix and read by a single ASIC. The FPGA reads the sparse output from the ASICs and reconstructs for each event a full image of the light pattern coming from the LYSO matrix. This pattern can be then processed on-line or sent to the host PC for post-processing. Early tests were conducted by using a prototype board with single LYSO crystals of ${3.3} \textrm {mm}\times {3.3} \textrm {mm} \times {8} \textrm {mm}$ and dual layer staggered LYSO matrices. Results show that the ASIC can sustain input rates above 58 kHz on all its channels, with small variations depending on the discriminating thresholds, being this limit due its digital output stage. With the single crystals setup, we obtained an energy resolution of 10.7% at 511 keV and a coincidence time resolution of 420 ps FWHM. With the staggered matrix the obtained mean energy resolution was 16% on the top layer and 18% on the bottom layer. The flood maps obtained with the LYSO matrix setup show that the pixels on both the staggered levels are clearly identifiable.

Stretchable capacitive devices are instrumental for new‐generation multifunctional haptic technologies particularly suited for soft robotics and electronic skin applications. A majority of elongating soft electronics still rely on silicone for building devices or sensors by multiple‐step replication. In this study, fabrication of a reliable elongating parallel‐plate capacitive touch sensor, using nitrile rubber gloves as templates, is demonstrated. Spray coating both sides of a rubber piece cut out of a glove with a conductive polymer suspension carrying dispersed carbon nanofibers (CnFs) or graphene nanoplatelets (GnPs) is sufficient for making electrodes with low sheet resistance values (≈10 Ω sq−1). The electrodes based on CnFs maintain their conductivity up to 100% elongation whereas the GnPs‐based ones form cracks before 60% elongation. However, both electrodes are reliable under elongation levels associated with human joints motility (≈20%). Strikingly, structural damages due to repeated elongation/recovery cycles could be healed through annealing. Haptic sensing characteristics of a stretchable capacitive device by wrapping it around the fingertip of a robotic hand (ICub) are demonstrated. Tactile forces as low as 0.03 N and as high as 5 N can be easily sensed by the device under elongation or over curvilinear surfaces.

The importance of searching signals from “non-standard” physics has been growing in the last years, in spite of the astounding success of the Standard Model in predicting particle existence and behaviour. In particular the Lepton Flavor Violating (LFV) processes, and exspecially the µ → e + γ decay, are a very promising field to probe effect of physics beyond the Standard Model [1]. Thus the MEG experiment has been proposed and is in an advanced phase of construction at the Paul Scherrer Institute (PSI).

The MEG experiment started taking data in 2009 looking for the Standard Model suppressed decay μ → e + γ, which, if observed, can reveal Beyond Standard Model physics. It makes use of state-of-the art detectors optimized for operating in conditions of very high intensity, rejecting as much background as possible. The data taking ended August 2013 and an upgrade R&D is started to push the experimental sensitivity. The present upper limit on the decay Branching Ratio (BR) is presented, obtained with the subset of data from 2009 to 2011 run, together with a description of the key features of the upgraded detector.