Low loss HF band SOI wine glass bulk mode capacitive square-plate resonator

This paper reports on the design and electrical characterization of a single crystal silicon micromechanical square-plate resonator. The microresonator has been excited in the anti-symmetrical wine glass mode at a resonant frequency of 5.166 MHz and exhibits an impressive quality factor (Q) of 3.7 × 106 at a pressure of 33 mtorr. The device has been fabricated in a commercial foundry process. An associated motional resistance of approximately 50 kΩ using a dc bias voltage of 60 V is measured for a transduction gap of 2 νm due to the ultra-high Q of the resonator. This result corresponds to a frequency-Q product of 1.9 × 1013, the highest reported for a fundamental mode single-crystal silicon resonator and on par with some of the best quartz crystal resonators. The results are indicative of the superior performance of silicon as a mechanical material, and show that the wine glass resonant mode is beneficial for achieving high quality factors allowed by the material limit. © 2009 IOP Publishing Ltd.

Component-based approach to the holonic control of a robot assembly cell

The aim of this paper is to describe the implementation of a new approach for the introduction of so called 'holonic manufacturing' principles into existing production control systems. Such an approach is intended to improve the reconfigurability of the control system to cope with the increasing requirements of production change. A conceptual architecture is described and implemented in a robot assembly cell to demonstrate that this approach can lead to a manufacturing control system which can adapt relatively simply to long-term change. A design methodology and migration strategy for achieving these solutions using conventional hardware is proposed to develop execution level of manufacturing control systems.

Robust approach to dynamic statistical process control

Statistical Process Control (SPC) technique are well established across a wide range of industries. In particular, the plotting of key steady state variables with their statistical limit against time (Shewart charting) is a common approach for monitoring the normality of production. This paper aims with extending Shewart charting techniques to the quality monitoring of variables driven by uncertain dynamic processes, which has particular application in the process industries where it is desirable to monitor process variables on-line as well as final product. The robust approach to dynamic SPC is based on previous work on guaranteed cost filtering for linear systems and is intended to provide a basis for both a wide application of SPC monitoring and also motivate unstructured fault detection.

Evaluacion de bicarbonato de sodio, caldo vizosa y caldo bordeles en el control de la cenicilla (Erysiphe cichoracearum DC) en el cultivo de pipian (Cucurbita pepo L.), en Apacunca, Chinandega

El pipián ( Cucurbita pepo.) tiene su origen en el continente americano, por lo que la diversidad genética presente en el continente ha permitido muchas denominaciones populares. El trabajo de investigación se llevó a cabo en la Reserva de Recursos Genéticos de Apacunca, en la comunidad de Asquespalapa, el objetivo fue encontrar opciones de bajo costo y no dañinas a la salud humana y ambiente, para el control de la Cenicilla del Pipián ( Erysiphe cichoracearum), Los tratamientos fueron arreglados en un diseño de bloque completo al azar (B.C.A) con tres réplicas. El ensayo fue establecido en una Area de 100m2. Cada parcela experimental estuvo constituida por 4 surcos de 6 metros de largo con distancia entre plantas de 1 metro. El área total de cada parcela experimental fue de 18 metros cuadrados. La parcela útil estuvo constituida por las 8 plantas centrales de cada parcela experimental. La variedad utilizada para el estudio fue la Criolla. Los tratamientos probados consistieron en tres caldos minerales preventivos y un testigo, se realizó un análisis de varianza con un 95 % de confianza y separación de medias según Tukey LSD (∞= 0.05) y análisis de beneficio costo. Los resultados indican que el caldo vizosa mostró únicamente entre un 5 y 10% de afectación en cuanto a la incidencia y severidad de la enfermedad, en segunda categoría encontramos al caldo bordelés con un 15 y 20 %, de afectación. En cuanto a la relación beneficio costo se determinó que el caldo Vizosa es un producto rentable ad amas de mantener la parcela libre de patógenos da un resultado económico en cuanto a la producción y compensación a la hora de vender en el mercado.

Arc Root Motions In An Argon-Hydrogen Direct-Current Plasma Torch At Reduced Pressure

Arc root motions in generating dc argon-hydrogen plasma at reduced pressure are optically observed using a high-speed video camera. The time resolved angular position of the arc root attachment point is measured and analysed. The arc root movement is characterized as a chaotic and jumping motion along the circular direction on the anode surface.