Resonant coupler-based tunable add after-drop filter insilicon-oxynitride technology for WDM networks

We present a tunable add-drop filter for wavelength division multiplexing (WDM) networks based on the resonant coupler (RC) principle. The device operates in the 1550-nm window with a wavelength spacing of 1.6 nm (200 GHz) and a periodicity of 6.4 nm (800 GHz). The splitting of the add and drop functions in an add-after-drop configuration results in extremely low homowavelength crosstalk and allows the individual design of the add and drop subfunctions to be optimized. The design of the flat-passband drop function is presented in detail. The compact filter is realized in high-index-contrast silicon-oxynitride technology, which permits small bending radii of 1.5 mm. Phase errors in the delay lines of the RC devices are compensated using the thermooptic effect, which is also used to tune the device. Measurement results on packaged devices show fiber-to-fiber losses of between 5 and 7 dB. The isolation of the transit WDM channels to the drop port is greater than 27 dB, and the rejection of the drop channel is 33 dB. The components are polarization insensitive and have been integrated in an add-drop WDM subsystem     

Vodka production from potato (Solanum tuberosum L.) using three Saccharomyces cerevisiae isolates

The efficacy of three strains of Saccharomyces cerevisiae in the production of vodka from potato hydrolysate was evaluated. For each isolate, two treatments were performed: one containing potato hydrolysate (11% w/w of soluble solids) and the other containing potato hydrolysate supplemented with sucrose (17% w/w) in the fermentation medium. The best results were obtained using a baker's yeast in the second treatment, which showed higher substrate‐to‐product conversion (0.47 g ethanol g^?1 total reducing sugars), higher fermentation yield (91.4%) and a higher ethanol content (6.05% v/v). Following fermentation, the medium was clarified using centrifugation, and two successive distillations and filtrations were conducted. The results were examined by referring to the standards for vodka, as established by Brazilian legislation. The ethanol concentration (39.7% v/v) fell within the legally stipulated range, and the levels of copper and furfural remained undetectable. However, the methanol (35.04 mg 100 mL^?1 of anhydrous alcohol) content and the levels of some secondary compounds (148.33 mg 100 mL^?1) were both higher than the guidelines (20 and ≤50 mg 100 mL^?1, respectively). Copyright © 2016 The Institute of Brewing & Distilling     

Simultaneous optimization of response variables in protein mixture formulation: constrained simplex method approach

Summary The objective of this study was to test a complex constrained simplex, direct search, sequential method for the optimization of a ternary mixture of protein ingredients used in a formulation for the preparation of a milk drink regularly consumed in institutional nutritional programmes. Three proteins [hydrolysed gelatine (HG), wheat gluten (WG) and soybean protein isolate (SPI)] were mixed according to a simplex‐centroid design, in order to explore the possible synergies between the sensory, nutritional and economic attributes. Mixtures containing different proportions of the three ingredients were submitted to sensory, nutritional and economic evaluations. All responses were modelled using Scheffé's canonical equations. A microinformatics application was developed in order to permit optimization to be computed. The optimum solution obtained by this non‐linear programming was HG = 20%, WG = 27% and SPI = 53%, suggesting that the program is efficient and flexible enough for multiresponse optimization. The optimal point behaviour of the entry variables (HG, WG and SPI) can be monitored with graphs of the trace plot type, in which the proportion of two variables is fixed and the third is allowed to vary in relation to the desired response.     

An 8-bit Folding A/D Converter with a New Interpolation Technique

This paper proposes a new interpolation technique for application in a folding A/D converter with interpolation. However, there is not a specific interpolation circuit because this interpolation technique is applied to the folding encoder circuit and to the master latches of the A/D converter. This interpolation technique adds some transistors in the folding encoder circuit, and it adds only three transistors to some master latches. An 8-bit A/D converter has been designed and implemented in a 0.8 μm BiCMOS process, at F _T of 12 GHz to evaluate the proposed interpolation technique.     

Oil crops for biodiesel production in Italy

There is an energy advantage in methylester production using sunflower, rapeseed and soybean as crop suppliers of energy, the process being practicable in terms of technique and energy gain. The three oilseed crops considered in this work are suitable for considerable reduction of inputs with consequent energy savings and low environmental impact. Nevertheless, because of its low arable surface area, the number of available hectares being static, Italy is oriented towards intensive management. As a consequence, optimisation of cropping techniques is the main strategy to be pursued for higher crop yields for methylester production.     

Thermal behavior of visible AlGaInP-GaInP ridge laser diodes

The thermal behavior of visible AlGaInP-GaInP ridge laser diodes was investigated numerically and experimentally. It is shown that various parameters critically influence the thermal resistance, R , of such devices. R is inversely proportional to the thermal conductivity of the heat sink. A substantial improvement in R is achieved for junction-side-down mounting compared to junction-side-up. R depends strongly on the width, w, of the ridge, and this effect is different for junction-side-up or junction-side-down mounting. In the first case, R~log(w) and in the second, R~1/w. The thickness of the soldering material is a sensitive parameter which may increase the value of R by up to 15 K/W. For junction-side-up mounted devices, the top metallization layer has a very favorable effect: a 1-μm-thick gold layer reduces R by 30%. It is shown that when a laser is switched on, the thermal steady state is reached in the millisecond time range. The experimental results show very good agreement with numerical data     

Linear regulators and observers

The design of a regulator system using a constant gain observer in the feedback loop is discussed. By examining the poles of the closed-loop plant and observer, it is explicitly clear that the closed-loop response is jointly determined by the plant and observer poles and zeros.