New analogue switch circuit having very low forward resistance

A new circuit realisation for an analogue switch is reported. The main feature of the proposed design is the low value of the forward resistance as compared with commercial switches. Experimental data confirming the performance of the circuit are also included

Switched-capacitor neural networks for linear programming

A circuit for online solving of linear programming problems is presented. The circuit uses switched-capacitor techniques and is thus suitable for monolithic implementation. The connection of the proposed circuit to analogue neural networks is also outlined.Comisión Interministerial de Ciencia y Tecnología ME87-000

Chaos From Switched-Capacitor Circuits: Discrete Maps

A special-purpose analog computer made of switched-capacitor circuits is presented for analyzing chaos and bifurcation phenomena in nonlinear discrete dynamical systems modeled by discrete maps *n + t = fan)-Experimental results are given for four switched-capacitor circuits described by well-known discrete maps; namely, the logistic map, the piecewise-linear unimodal (one-hump) map, the H é non map, and the Lozi map

Chaos via a piecewise-linear switch ed-capacitor circuit

A nonlinear switched-capacitor circuit that generates chaotic signals is reported. The circuit is described by a first-order piecewise-linear discrete equation that exhibits a chaotic dynamics. Experimental results illustrating the circuit performance and its use as a noise generator are included.Comisión Interministerial de Ciencia y Tecnología 3467-8

Nonlinear Switched-Capacitor Networks: Basic Principles and Piecewise-Linear Design

The applicability of switched-capacitor (SC) components to the design of nonlinear networks is extensively discussed in this paper. The main objective is to show that SC's can be efficiently used for designing nonlinear networks. Moreover, the design methods to be proposed here are fully compatible with general synthesis methods for nonlinear n -ports. Different circuit alternatives are given and their potentials are evaluated.Office of Naval Research (USA) N00014-76-C-0572Comisión Interministerial de Ciencia y Tecnología 0235/81Semiconductor Research Corporation (USA) 82-11-00

Compacity of soils developed over Tertiary-Quanernary sediments in the Terra Cha area (Lugo)

[Abstract] Using a gamma probe, bulk density has been measured for nine profiles from 20 cm depth to depths ranging from 90 to 15Ocm. The intent ofthis work was to assesss total porosity variability withinand between sites at an area characterized by an abrupt textural change. Bulk density values obtained at both tertiary and quaternary subsoillayers are significantly higher and show less variability between sites and also more repeteability along the time than bulk density values obtained at the surface A and B soil horizons. In addition, Hg intrusion porosimetry demonstrated a decrease of the average pore diameter with depth and thus with age of the soil and sediement materials

Hydrogen storage properties of magnesium borohydride infiltrated in silica aerogel using solvated and pressure methods

In this work, the polymorphic α-magnesium borohydride form was infiltrated by wet impregnation using tetrahydrofuran (THF) as solvent and subcritical carbon dioxide as innovative drying process. Pressure infiltration at high temperature was also tested as another promising method for confinement. After infiltration, onset decomposition temperature was reduced from 280 °C into 220 °C using high pressure infiltration and down to 100 °C using wet impregnation followed by CO2 drying. Faster kinetics were obtained in both cases due the possible particle size reduction in the precipitation process of the complex hydride and the presence of silica, which could behave as an additive. It is the first time that this complex borohydride is 6.1 wt% H2 reversible performing the rehydrogenation at moderate conditions of 390 °C and 120 bar H2 using silica as support. Different values were obtained after infiltration method due to the different intermediates that were obtained after the first dehydrogenation

Design and operation of a rainfall simulator for field studies of runoff and soil erosion

[Abstract] The present paper describes the design, construction, calibration and operation of a spray rainfall simulator . The design of the plots used for the purpose of this study is also described in order to determine hydrological and erosion parameters. Selected rainfall intensity of 64 mm h- 1 are representative of heavy storm conditions in Galicia. Drop size distribution results in these conditions , a D5 0of 1.2 mm, were similar to those calculated for natural rainfall by BUBENZER (1979). Fall velocities reached were between 75 and 100% terminal velocity, depending on drop diameter and 13.05 Jm- 2m m- 1kinetic energy was obtained Surface area of the plots used was 1 m2, surronded by a metal structure connected to a V-shaped system to collect the surface runoff and sediment produced in the different experiments

Sufficiency ranges (sr) and deviation from optimum percentage (dop) references for leaf blade and petiole analysis in ‘Red Grenache’ grapevines

[EN] [Aim] To obtain specific references for the nutritional diagnosis of ten essential nutrients for leaf blade and petiole of ‘red Grenache’ (Vitis vinifera L.).[Methods and results] Leaf blades and petioles from 36 vineyards of ‘red Grenache’ (Vitis vinifera L.) grafted on Richter 110 were collected and analyzed at flowering and veraison between 1992 and 2008. Using the compiled data bank, nutritional references for ten elements (N, P, K, Ca, Mg, Fe, Mn, Zn, Cu and B were calculated. Optimal values were those around the central data (μ ± 0.25σ), while excessive and deficient values were those beyond the tails of the distribution (μ ± 0.84σ). Percentile calculation was performed when transformations to normal distributions became unlikely.[Conclusion] References for Sufficiency Ranges (SR) and Deviation from Optimum Percentage (DOP) methods were obtained for those ten nutrients studied.[Significance and impact of the study] The proposed ‘red Grenache’ references for leaf blade and petiole contribute to the improvement of the accuracy of ‘red Grenache’ grapevine nutrient diagnosis based on tissue analysis. These references are a guide to assess the nutritional status of ‘red Grenache’ grapevine around the world in general and, with higher accuracy, for the Rioja region and areas with similar vineyard conditions.[FR] [Objectif] Obtenir des références spécifiques pour le diagnostic nutritionnel de dix éléments nutritifs essentiels au limbe et pétiole de ‘Grenache noir’ (Vitis vinifera L.).[Méthodes et résultats] Les limbes et pétioles des feuilles provenant de 36 vignobles de ‘Grenache noir’ (Vitis vinifera L.) greffés sur Richter 110 ont été recueillis et analysés à la floraison et à la véraison entre 1992 et 2008. À partir de la banque de données, des références nutritionnelles pour dix éléments (N, P, K, Ca, Mg, Fe, Mn, Zn, Cu et B) ont été calculées. Les valeurs optimales étaient celles autour de la valeur centrale de données (μ ± 0.25σ), tandis que les valeurs excessives et déficientes étaient celles au-delà des extrémités de la distribution (μ ± 0.84σ). Lorsque les valeurs n’étaient pas conformes à une distribution normale et que la transformation logarithmique n’était pas efficace, les percentiles correspondants ont été calculés.[Conclusion] Les références pour les méthodes Gammes de Suffisance et Déviation du Pourcentage Optimal ont été obtenues pour les dix nutriments étudiés.[Signification et impact de l’étude] Les références pour le limbe et le pétiole de ‘Grenache noir’ contribuent à l’amélioration du diagnostic de nutriments. Ces références sont un guide pour évaluer l’état nutritionnel des vignes de ‘Grenache noir’ dans le monde et, avec une plus grande précision, dans la région de Rioja et dans d’autres régions similaires.This study was supported by the National Institute of Agricultural Research (Spain) and the Regional Government of La Rioja (Spain) with Projects INIA-SC00-016, PR-01-03, PR-01-04 and PR-03-05, among others. We also thank Mrs. M. Carmen Arroyo, the staff at the Regional Laboratory of La Grajera (La Rioja), the staff at the Viticulture and Oenology Section (SIDTA-ICVV), and the vine growers who helped develop the database.Peer Reviewe