Synthetic TDR Measurements for TEM and GTEM Cell Characterization

This paper describes the main features of the timedomain reflectometry (TDR) measurement technique and, in particular, the TDR analysis performed using a proper operating mode of the vector network analyzer (VNA), which is called synthetic TDR. Furthermore, some results of reflection measurement, which aim to characterize the impedance behavior of transverse electromagnetic (TEM) and gigahertz TEM cells by means of a commercial VNA in time-domain mode, are presented

Analysis of knee strength measurements performed by a hand-held multicomponent dynamometer and optoelectronic system

The quantification of muscle weakness is useful to evaluate the health status and performance of patients and athletes. In this paper, we proposed a novel methodology to investigate and to quantify the effects induced by inaccuracy sources occurring when using a hand-held dynamometer (HHD) for knee strength measurements. The validation methodology is based on the comparison between the output of a one-component commercial HHD and the outputs of a six-component load cell, comparable in dimension and mass. An optoelectronic system was used to measure HHD positioning angles and displacements. The setup allowed to investigate the effects induced by: 1) the operator's ability to place and to hold still the HHD and 2) ignoring the transversal components of the force exchanged. The main finding was that the use of a single component HHD induced an overall inaccuracy of 5% in the strength measurements if the angular misplacements are kept within the values found in this paper (≤15°) and with a knee range of motion ≤22°. Extension trials were the most critical due to the higher force exerted, i.e., 249.4 ± 27.3 versus 146.4 ± 23.9 N of knee flexion. The most relevant source of inaccuracy was identified in the angular displacement on the horizontal plane

Evolution and Recent Developments of the Gaseous Photon Detectors Technologies

The evolution and the present status of the gaseous photon detectors technologies are reviewed. The most recent developments in several branches of the field are described, in particular the installation and commissioning of the first large area MPGD-based detectors of single photons on COMPASS RICH-1. Investigation of novel detector architectures, different materials and various applications are reported, and the quest for visible light gaseous photon detectors is discussed. The progress on the use of gaseous photon detector related techniques in the field of cryogenic applications and gaseous or liquid scintillation imaging are presented.Comment: NDIP 2017 Proceedings, review, submitted to Nuc. Inst. Methods

Direct comparison of high voltage breakdown measurements in liquid argon and liquid xenon

As noble liquid time projection chambers grow in size their high voltage requirements increase, and detailed, reproducible studies of dielectric breakdown and the onset of electroluminescence are needed to inform their design. The Xenon Breakdown Apparatus (XeBrA) is a 5-liter cryogenic chamber built to characterize the DC high voltage breakdown behavior of liquid xenon and liquid argon. Electrodes with areas up to 33 cm2 were tested while varying the cathode-anode separation from 1 to 6 mm with a voltage difference up to 75 kV. A power-law relationship between breakdown field and electrode area was observed. The breakdown behavior of liquid argon and liquid xenon within the same experimental apparatus was comparable

In situ characterization of two wireless transmission schemes for ingestible capsules

We report the experimental in situ characterization of 30-40 MHz and 868 MHz wireless transmission schemes for ingestible capsules, in porcine carcasses. This includes a detailed study of the performance of a magnetically coupled near-field very high-frequency (VHF) transmission scheme that requires only one eighth of the volume and one quarter of the power consumption of existing 868-MHz solutions. Our in situ measurements tested the performance of four different capsules specially constructed for this study (two variants of each transmission scheme), in two scenarios. One mimicked the performance of a body-worn receiving coil, while the other allowed the characterization of the direction-dependent signal attenuation due to losses in the surrounding tissue. We found that the magnetically coupled near-field VHF telemetry scheme presents an attractive option for future, miniturized ingestible capsules for medical applications

Multiple-fault detection methodology based on vibration and current analysis applied to bearings in induction motors and gearboxes on the kinematic chain

© 2016 Juan Jose Saucedo-Dorantes et al. Gearboxes and induction motors are important components in industrial applications and their monitoring condition is critical in the industrial sector so as to reduce costs and maintenance downtimes. There are several techniques associated with the fault diagnosis in rotating machinery; however, vibration and stator currents analysis are commonly used due to their proven reliability. Indeed, vibration and current analysis provide fault condition information by means of the fault-related spectral component identification. This work presents a methodology based on vibration and current analysis for the diagnosis of wear in a gearbox and the detection of bearing defect in an induction motor both linked to the same kinematic chain; besides, the location of the fault-related components for analysis is supported by the corresponding theoretical models. The theoretical models are based on calculation of characteristic gearbox and bearings fault frequencies, in order to locate the spectral components of the faults. In this work, the influence of vibrations over the system is observed by performing motor current signal analysis to detect the presence of faults. The obtained results show the feasibility of detecting multiple faults in a kinematic chain, making the proposed methodology suitable to be used in the application of industrial machinery diagnosis.Postprint (published version