A high performance LIA-based interface for battery powered sensing devices

This paper proposes a battery-compatible electronic interface based on a general purpose lock-in amplifier (LIA) capable of recovering input signals up to the MHz range. The core is a novel ASIC fabricated in 1.8 V 0.18 µm CMOS technology, which contains a dual-phase analog lock-in amplifier consisting of carefully designed building blocks to allow configurability over a wide frequency range while maintaining low power consumption. It operates using square input signals. Hence, for battery-operated microcontrolled systems, where square reference and exciting signals can be generated by the embedded microcontroller, the system benefits from intrinsic advantages such as simplicity, versatility and reduction in power and size. Experimental results confirm the signal recovery capability with signal-to-noise power ratios down to -39 dB with relative errors below 0.07% up to 1 MHz. Furthermore, the system has been successfully tested measuring the response of a microcantilever-based resonant sensor, achieving similar results with better power-bandwidth trade-off compared to other LIAs based on commercial off-the-shelf (COTS) components and commercial LIA equipment

Generation of rotationally dominated galaxies by mergers of pressure-supported progenitors

Through the analysis of a set of numerical simulations of major mergers between initially non-rotating, pressure supported progenitor galaxies with a range of central mass concentrations, we have shown that: (1) it is possible to generate elliptical-like galaxies, with v/sigma > 1 outside one effective radius, as a result of the conversion of orbital- into internal-angular momentum; (2) the outer regions acquire part of the angular momentum first; (3) both the baryonic and the dark matter components of the remnant galaxy acquire part of the angular momentum, the relative fractions depend on the initial concentration of the merging galaxies. For this conversion to occur the initial baryonic component must be sufficiently dense and/or the encounter should take place on a orbit with high angular momentum. Systems with these hybrid properties have been recently observed through a combination of stellar absorption lines and planetary nebulae for kinematic studies of early-type galaxies. Our results are in qualitative agreement with such observations and demonstrate that even mergers composed of non-rotating, pressure-supported progenitor galaxies can produce early-type galaxies with significant rotation at large radii.Comment: 5 pages, 6 figures, 2 tables. Accepted for publication in A&A Letter

Portable lock-in amplifier for microcantilever based sensor array. Application to explosives detection using Co-BEA type zeolites as sensing materials

Recent advances in microcantilever-based sensors have led to a significant increase in sensitivity, making them a competitive solution in highly demanding applications as explosives detection. However, these sensors face severe challenges related to: reliability, sensitivity, reproducibility and throughput; that have yet to be solved for commercial applications. This paper describes our efforts in this direction, particularly on the reproducible detection of nitroaromatic type explosives by means of parallelization combined with: i) nanoporous solids as sensing materials; and, ii) a portable lowpower electronic readout interface capable of both excitation and measurement of the multisensing platform. The response of the sensor array, comprising 4 microcantilevers, due to presence of 2-nitrotoluene, a common explosive taggant, has been properly monitored. The obtained results with 4 identical Co-BEA coated Si microcantilevers underline the importance of a proper sensing material degassing on the sensor performance

Portable low-power electronic interface for explosive detection using microcantilevers

Microcantilevers have been recently revealed as a highly effective technique for gas detection at trace level when acting as chemical sensors. However, an important milestone still remains to achieve a full-scale development in commercial applications: the cumbersome systems traditionally used to read-out its responses. To accomplish this, a portable low-power electronic interface, based on an analog lock-in amplifier processing square signals, which is fully capable of creating the excitation signal as well as obtaining the response values from resonating microcantilevers functionalized with zeolite based coatings has been herein attempted. The so obtained read-out results are in good agreement with the commercial lock-in amplifier's measurements, demonstrating the accuracy and reliability of the electronic interface. Finally, its performance has been validated for 2-nitrotoluene (o-MNT) detection at ppm V level, as an example of an explosive-related molecule, with BEA zeolite coated microcantilevers. Theoretical limit of detection (LOD) values below 100 ppb have been obtained for Co exchanged BEA modified sensors

Explosives detection by array of Si µ-cantilevers coated with titanosilicate type nanoporous materials

An array comprising 4 Si microcantilevers coated with nanoporous ETS-10 crystals sub-micrometric in size has been deployed as a multisensing platform for 2-nitrotoluene (an explosive related molecule) recognition. For such purposes, the adsorption properties of synthetic microporous ETS-10 titanosilicate type materials have been tailored by means of the Si/Ti ratio, and surface grafting with organic groups (amine, imidazol). Our general strategy for vapor detection of explosives involves the combination of Si based nanoporous solids as sensing materials and resonating Si cantilevers provided with self-heating elements as tiny microbalances (mass sensitivity factors ~18 Hz/ng). Particularly for this work, ETS-10 type titanosilicates with promoted basic properties (Si/Ti=4, -NH2 anchored on the external surface) exhibit the higher affinity towards nitroaromatic derivatives as electron defficient molecules. A high remarkable hydrophilic character is shown by titanosilicates modified by covalent linkage with imidazole based organosilane (above 17% wt. water uptake at room temperature). Accounting from such versatile sorption behavior, the family of nanoporous ETS-10 crystals has been deployed by microdropping technique over the 8 Si-microcantilevers chip. By means of a portable lowpower electronic interface capable of the simultaneous excitation and measurement of 4 sensor output signals, such multisensing platform has been successfully applied for 2-nitrotoluene detection at trace level

Explosives Detection by Array of Si µ -Cantilevers Coated with Titanosilicate-Type Nanoporous Materials

An array comprising four Si µ -cantilevers coated with nanoporous functionalized ETS-10 crystals sub-micrometric in size has been developed as a multisensing platform for explosives recognition in vapor phase. The detection capabilities of the proposed device have been tested for common taggants such as 1-methyl-2-nitro-benzene (o-MNT)] and explosives (commercial detonation cord, a plastic tube filled with pentaerythritol tetranitrate (PETN); and C-4, a mixture of cyclotrimethylenetrinitramine (RDX), binders and plastifiers). The general strategy for the detection of explosives in vapor phase is based on the characteristic fingerprint each one produces as a result of the dissimilar chemical interactions between the ETS-10 coated µ -cantilevers and the target molecules emanating from the explosives and swept by ambient air. A portable lock-in amplifier has been implemented to exploit the truly benefits of the array in terms of portability, reduced size, and energy consumption. Such low-power electronic interface is capable of creating the excitation signal as well as obtaining the response values of four resonating µ -cantilevers simultaneously. The resulting sensing platform has successfully been applied for the o-MNT, PETN, and RDX detection at trace level

Vacuum Energy and Renormalization on the Edge

The vacuum dependence on boundary conditions in quantum field theories is analysed from a very general viewpoint. From this perspective the renormalization prescriptions not only imply the renormalization of the couplings of the theory in the bulk but also the appearance of a flow in the space of boundary conditions. For regular boundaries this flow has a large variety of fixed points and no cyclic orbit. The family of fixed points includes Neumann and Dirichlet boundary conditions. In one-dimensional field theories pseudoperiodic and quasiperiodic boundary conditions are also RG fixed points. Under these conditions massless bosonic free field theories are conformally invariant. Among all fixed points only Neumann boundary conditions are infrared stable fixed points. All other conformal invariant boundary conditions become unstable under some relevant perturbations. In finite volumes we analyse the dependence of the vacuum energy along the trajectories of the renormalization group flow providing an interesting framework for dark energy evolution. On the contrary, the renormalization group flow on the boundary does not affect the leading behaviour of the entanglement entropy of the vacuum in one-dimensional conformally invariant bosonic theories.Comment: 10 pages, 1 eps figur

Análisis de imágenes 2D para la optimización de endoprótesis con carburo de silicio biomórfico

En el presente trabajo se muestra un análisis de diferentes estructuras óseas que se obtuvieron por imágenes de tomografías en dos dimensiones o “planas”, de las cuales se reconstruyen para obtener una visualización para el diagnóstico médico y el desarrollo de endoprótesis con materiales biocompatibles

(Re)Conceptualizing decision-making tools in a risk governance framework for emerging technologies—the case of nanomaterials

The utility of decision-making tools for the risk governance of nanotechnology is at the core of this paper. Those working in nanotechnology risk management have been prolific in creating such tools, many derived from European FP7 and H2020-funded projects. What is less clear is how such tools might assist the overarching ambition of creating a fair system of risk governance. In this paper, we reflect upon the role that tools might and should play in any system of risk governance. With many tools designed for the risk governance of this emerging technology falling into disuse, this paper provides an overview of extant tools and addresses their potential shortcomings. We also posit the need for a data readiness tool. With the EUs NMP13 family of research consortia about to report to the Commission on ways forward in terms of risk governance of this domain, this is a timely intervention on an important element of any risk governance system

Differences in self-perceived OHRQoL between fully dentate subjects and edentulous patients depending on their prosthesis type, socio-demographic profile, and clinical features

Objectives: This observational cross-sectional study aimed to evaluate and compare the oral health-related quality of life (OHRQoL) and clinical performance between dentate subjects and edentulous patients restored with conventional dentures or implant overdentures. Methods: 85 edentulous patients were grouped as follows: Group-1 (CD): conventional denture wearers (n = 42), and Group-2 (IO): implant-retained overdenture wearers (n = 43). For the OHRQoL comparisons, a control group of subjects with a healthy natural dentition (Group-3, ND; n = 50) was included. Participants completed three validated questionnaires (OHIP-14sp, OHIP-20sp, and QoLIP-10). Socio-demographic data, prosthesis-related factors, clinical condition of the mouth, and patient subjective evaluations, were gathered. Descriptive and non-parametric probes were run (α = 0.05). Results: The ND group was the most unsatisfied (OHIP-14sp; p ≤ 0.001). The OHIP-20sp attributed significantly worse Psychological disability (p = 0.029) and Handicap (p = 0.027) to CD wearers when compared to IO wearers. The CD group showed the significantly highest need for relining (p = 0.041), and the lowest retention (p = 0.011). The OHIP-14sp disclosed a significantly worse OHRQoL for those volunteers who had a job (p = 0.003), a basic education instead of a secondary one (p = 0.022), and no partner (p = 0.006). Conclusions: The overall OHRQoL was comparable for both prosthodontic groups, being modulated by sociodemographic and prosthesis-related features. Nonetheless, CD wearers presented prosthetic complications more frequently. Clinical significance: While dentate subjects were the most critical about their oral condition and its repercussion in their life, implant overdenture wearers tended to observe a better OHRQoL and clinical performance compared to conventional denture wearers