Differential temperature sensors: Review of applications in the test and characterization of circuits, usage and design methodology

Differential temperature sensors can be placed in integrated circuits to extract a signature ofthe power dissipated by the adjacent circuit blocks built in the same silicon die. This review paper firstdiscusses the singularity that differential temperature sensors provide with respect to other sensortopologies, with circuit monitoring being their main application. The paper focuses on the monitoringof radio-frequency analog circuits. The strategies to extract the power signature of the monitoredcircuit are reviewed, and a list of application examples in the domain of test and characterizationis provided. As a practical example, we elaborate the design methodology to conceive, step bystep, a differential temperature sensor to monitor the aging degradation in a class-A linear poweramplifier working in the 2.4 GHz Industrial Scientific Medical—ISM—band. It is discussed how,for this particular application, a sensor with a temperature resolution of 0.02 K and a high dynamicrange is required. A circuit solution for this objective is proposed, as well as recommendations for thedimensions and location of the devices that form the temperature sensor. The paper concludes with adescription of a simple procedure to monitor time variability.Postprint (published version

Bitcoin

Este articulo analiza Bitcoin, comenzando por explicar en qué consiste, como funciona esta criptomoneda descentralizada y sus principales características. Recordando las diferentes etapas del dinero hasta llegar a la actualidad y analizando las características que tiene en común con el dinero fiduciario que no es más que el dinero que usamos a día de hoy. Además, observando cuales son las posibles implicaciones económicas de bitcoin en un futuro, y como conclusión a este articulo cabe decir que Bitcoin tiene un gran potencial para convertirse en una moneda operativa, pero que a día de hoy no lo es. Bitcoin tiene un gran obstáculo y es la alta volatilidad, debido a ello es imposible que sea usada como moneda operativa. Este gran inconveniente la convierte más en un activo financiero que en una moneda operativa por lo que para superar este gran obstáculo, deberá ser respaldada y regulada por algún gobierno o sistema financiero, algo imposible actualmente observando la propia naturaleza de Bitcoin, al no estar gestionada por ningún agente externo, de hecho, no se sabe a ciencia cierta quien fue su fundador, es una moneda que se basa únicamente en la oferta y la demanda. Y aunque su valor no deja de aumentar en los últimos años el hecho de ser tan altamente volátil hace que no sea una moneda operativa como puede ser el Euro. Seguramente nunca será tan usada como el Euro o el Dólar, pero lo que no podemos negar es que tiene potencial suficiente para ser una alternativa a estas monedas. Bitcoin es a día de hoy un activo financiero objeto de muchas especulaciones financieras, pero no es en ningún caso una moneda operativa como tal. Tras la investigación y recopilación de información sobre Bitcoin , he de decir que tiene algunas ventajas con respecto a otras monedas como el Euro , como puede ser que no esté gestionada por un banco central, pero esa misma característica que hace de Bitcoin una ventaja , lo convierte a su vez en una desventaja , ya que al no estar regulada ni gestionada por ningún agente externo crea desconfianza en sus usuarios que pueden pensar que en cualquier momento puede caer su valor si existe una crisis de confianza en la moneda y nadie podría intentar resolver este problema. Como conclusión, Bitcoin es más un activo financiero que una moneda operativa, aunque tiene un gran potencial

Fast and accurate methodology for direct mercury determination in hair and nails

A solvent-free, easy, fast and waste-free methodology was developed for the determination of total mercury levels in hair and nails. Samples were taken from several volunteers and directly analysed, with levels of mercury in the range between 0.5 and 8 ng/mg. The influence of quantity of hair, as well as the addition of small amount of solvent and the necessity of previous treatment were studied. Also, a history of mercury exposure was provided by the distance of the hair from the scalp of each volunteer, the results of which were correlated with fish consumption. Furthermore, a short study of mercury in nails was carried out and correlated to the results from hair mercury levels. A small quantity of 5 mg of hair with an addition of 50 μL of water to the sample without previous treatment was adequate to get a representative result in less than 10 minutes. The accuracy of the proposed method was confirmed by analysing certified reference materials including Coal Fly Ash-NIST SRM 1633b, Fucus-IAEA 140 and three unpolished Rice Flour NIES-10. The observed results were found to be in good agreement with the certified values

On the Insurmountable Size of Truss-like Structures

Galileo postulated the existence of an insurmountable size for stone columns bearing a useful load as the size for which the structure is only able to resist its self-weight. Herein a method for the determination of the unsurmountable size for truss-like structures is shown, given the form of these structures and the ratio between the allowable stress and the specific weight of the material (the material structural scope). Three types of bars are considered: straight bars, with solid and hollow rectangular cross-section, and catenary bars with circular cross-section —a limit and theoretical case for estimating a meaningful upper bound of the structural scope—. An approximate rule to estimate the structural efficiency —here named GA rule— is shown, and is compared with numerical solutions using the proposed method

Rompiendo la inmunotolerancia en el entorno tumoral mediante el uso de vacunas oncolíticas

La inmunoterapia contra el cáncer está mejorando día a día y cobrando mayor importancia gracias a los avances que han mejorado el conocimiento del sistema inmune en esta enfermedad y el proceso de inmunoedición. Uno de los objetivos principales de estos tratamientos es revertir la inmunosupresión inherente al entorno tumoral para así facilitar la creación de una respuesta antitumoral específica por parte del sistema inmune. Una estrategia incluida en este grupo terapéutico es la de las vacunas oncolíticas, una herramienta que consiste en el uso de virus modificados genéticamente para destruir selectivamente las células cancerosas. La destrucción de células cancerosas se consigue de dos formas: a corto plazo (oncolisis por acción directa del virus) y a largo plazo (reversión de la inmunosupresión y generación de la respuesta inmune). A la hora de diseñar los virus no sólo se fomenta la especificidad por células tumorales sino que también se han probado con éxito otras modificaciones que les permitan conseguir una mayor respuesta del sistema inmunitario. El uso de virus oncolíticos ofrece una gran variedad de estrategias de tratamiento diferentes debido a la relativa facilidad con la que se puede modificar un virus para armarlo con genes que supongan un tratamiento más efectivo

Influence of solids concentration on the microstructure of suspension plasma sprayed Y-TZP/Al2O3/SiC composite coatings

The present research focuses on the effect of feedstock suspension solid concentration on the microstructure of suspension plasma sprayed Y-TZP/Al2O3/SiC composite coatings. For this purpose, concentrated aqueous suspensions were prepared at 10, 20 and 30 vol.% of particles. Suspensions were characterised in terms of colloidal stability, rheological behaviour and sedimentation trend. The optimised suspensions were plasma sprayed, and the thickness, porosity, amount of resolidified particles and SiC content in the coatings were evaluated by optical microscopy, scanning electron microscopy and X-ray diffraction. The results revealed that stand-off distance and suspension solid content have a strong and similar influence on the coating microstructure due to the great impact that these two parameters exerts on the energy that particles and substrate receive during plasma operation. Thus, cauliflower-like microstructure is well-developed in most of the coatings, particularly for longer distances and lower solid contents. Porosity and amount of resolidified particles in the coatings are favoured by increasing the stand-off distance and decreasing the solids content, while thickness is strongly affected by solids content variation. On the other hand, Rietveld method from X-ray diffraction showed that large amount of the initial SiC was preserved in the final coatings whereas this amount remains almost constant for the three suspension feedstock tested

Microstructure assessment of suspension plasma spraying coatings from multicomponent submicronic Y-TZP/Al2O3/SiC particles

In this research, Suspension Plasma Spraying (SPS) technique was used for the thermal deposition of a multicomponent mixture made up of an Y-TZP/Al2O3 matrix with SiC particles. Two suspensions of Y-TZP and Al2O3 with different SiC particles content (6 wt% and 12 wt%) were tested as feedstocks in the SPS process. Three stand-off distances were varied in order to assess coating microstructure and evaluate the presence of SiC in the final coatings. Coatings were characterised in terms of porosity, microstructure and phase distribution. The estimate of the amount of SiC in the coating was carried out by XRD technique. Findings showed typical cauliflower-like SPS microstructure which intensifies with stand-off distance. Coatings porosity varied significantly between 8% and 25% whereas minimum porosity was found for the intermedium stand-off distance of 40 mm. Microstructure analysis also revealed the presence of SiC particles in the coatings which was confirmed by EDX analysis, overall XRD tests as well as TG analysis. Finally, evaluation of SiC content in the final coatings by means of XRD analysis showed that most of SiC particles (c.a 80%) of the feedstocks were preserved in the final coatings

Effect of fructose-containing feedstocks on the microstructure of multicomponent coatings deposited by suspension plasma spraying

This work addressed to investigate the use of fructose as an additive in the water-based suspension feedstock of a Y-TZP/Al2O3/SiC multicomponent coating manufactured by suspension plasma spraying. The effect of fructose on suspension rheology and surface tension and on the microstructure and thermal conductivity of the resulting coatings was assessed. It was observed that addition of fructose slightly affected the rheological behaviour of the suspensions while a strong decrease in the surface tension of water occurred. The fructose addition led to the development of columnar-like structures, probably associated with its effect on surface tension. X-ray diffraction patterns in the final coating displayed that crystallinity of tetragonal zirconia formed when fructose was added whereas silicon carbide crystalline phase was practically preserved. The determination of thermal conductivity showed that the formation of a controlled columnar structure along with inter-columnar porosity can be beneficial for thermal insulation

Microfluidic rheology: A new approach to measure viscosity of ceramic suspensions at extremely high shear rates

This paper describes the operation principles of a micro-scale rheometry equipment based on the technology of microchannels on a chip and compares it with a conventional macro-scale rotational rheometer. Both techniques are used for the study of different solutions and suspensions of ceramic particles with different saccharides, which are subjected to a wide variety of shear rates from their preparation to their processing and injection in plasma spraying processes. The results have shown a clear difference between the rheological values obtained between both equipment, clearly influenced by the different measurement method. However, the microfluidic technique has higher accuracy to characterise fluids at high shear rates and low viscosities, and the apparent shear thickening observed in rotational rheometry for low viscosity samples due to wall slippage is not observed. In contrast, the fine microchannels of are easily clogged in concentrated suspensions

Importance of nuclear effects in the measurement of neutrino oscillation parameters

We investigate how models for neutrino-nucleus cross sections based on different assumptions for the nuclear dynamics affect the forecasted sensitivities to neutrino oscillation parameters at future neutrino facilities. We limit ourselves to the quasi-elastic regime, where the neutrino cross sections can be evaluated with less uncertainties, and discuss the sensitivity reach to theta_{13} and the CP violation phase at a prototype low-gamma beta-beam, mostly sensitive to the quasi-elastic regime.Comment: Error in cross section implementation corrected and sensitivities reevaluated accordingly. Relative performance of diffrent models and conclusions unchanged. Version to be published in PL