Efficient photodiode-waveguide coupling for hybrid integrated optical circuits

A GalnAsP edge-detecting photodiode was coupled with an SiO2-TiO2 single-mode waveguide in a simple hybrid integration scheme. The newly developed edge-detecting photodiode with a window region was used to improve photodiode durability.     

An intelligent visualisation and decision support system for decentralised wastewater treatment plants.

Current sanitation concepts of decentralised wastewater treatment and reuse raise the issue of monitoring and maintenance of such systems. To guarantee high quality of the recycled water, systems with high requirements concerning process technology are essential. With increasing numbers of decentralised treatment systems spread over far distances it will become more and more impossible and uneconomic to have expert personnel on site. Therefore, new visualisation and intelligent information systems are necessary. The paper describes the structure and 3D-demonstrations as a base for information visualisation. Up-to-date visualisation techniques, facilitating the cognition of context-adapted information, make it possible to maximise the amount of information presented to the user without overwhelming her or him. Concerning diagnosis and decision support systems in the domain of wastewater treatment, several interesting approaches are presented, estimating their applicability for decentralised wastewater treatment systems. The intelligent decision support system presented here consists of a combined ontology- and case-based reasoning system in addition to a process monitoring system. It is responsible for plausibility checks, error diagnosis, solution proposals, and optimisation suggestions.     

Buffer Capacity of Cheese Wheys

Titration and buffer capacity curves of Mozzarella, Cheddar and Cottage cheese-type wheys were studied at concentrations of 6–24% solids. Buffer maxima due to lactate and phosphate occurred at pH 3.2 – 4.0 and 5.6 – 7.0, respectively, and were dependent on the type and concentration of whey. Titration curves of all whey varieties intersected at pH 3.7. An equation was developed to define whey pH as a function of pH at dipping, concentration and level of HCI or NaOH (r = 0.99, p < 0.01). The pH of Mozzarella and Cheddar cheese-type whey decreased during concentration but the pH of Cottage cheese whey increased. This difference is explained by calcium-phosphate equilibria in whey.     

Experience with irradiation of LiSoR test section no. 3

LiSoR (liquid metal–solid metal reaction) loop is a unique facility which was designed to investigate simultaneously the influence of flowing lead bismuth eutectic (LBE), static stress and irradiation by protons onto steel that might be used as structural material in a future ADS (accelerator driven system) reactor. LiSoR is worldwide the first LBE loop that is under operation while it is irradiated at the same time.Up to now five LiSoR test sections have been irradiated. In this paper the experience on LiSoR no. 3 is presented including irradiation experiment and dissembling of the test section and EDM wire cutting of the samples. Additionally the results obtained by SEM and EDX analyses on LiSoR specimen and on beam window are shown whereby the most interesting outcome is the finding of an oxide layer, which was clearly identified by X-ray mapping. This layer is located directly in the irradiated area having a total thickness less than 1 μm. Additionally solidified LBE was detected on some areas of the samples but no wetting of the steel or penetration of LBE into the steel matrix was observed. No enrichment or dissolution of steel elements such as Fe and Cr could be detected on the surface near area. The steel surface is still smooth without any indications of corrosion attack.     

Spray deposition process study of SnO2silicon solar cells using orthogonal experimental design

With the “orthogonal experimental design” (OED), the dependence of conductivity and transparency of tin oxide films and open circuit voltage V_oc of SIS solar cells on the spray deposition process factors was studied. The OED technique was found to be a powerful method for realizing the best factor combination. Using OED, curves were obtained which clearly depict the effects of each factor on the SIS characteristics. The results of the experiments also illustrate exactly which variation in fabrication technique most affects the sheet resistance, V_oc, and film transparency. Under the optimal combination of conditions, a thin film doped with NH₄F was obtained, with about 90% transmission and a sheet resistance of about 80 Ω/□, along with an SIS structure with a V_oc of about 0.61 V.     

Interfacial stress singularities in a bimaterial wedge

In this paper methods of computing stress singularity factors for strain-hardening materials are reviewed. The methods are applied to calculation of these factors for a bimaterial wedge comprising two power-law hardening materials of arbitrary external and internal angles.     

Oxidation resistance and relative stability of some inter-4f alloys

Ten samarium-structure alloys have been oxidation tested in air to estimate the thermal oxidation parameter, T _p, and hence the ratio T _p/T_Sm, where T _Sm is the temperature of decomposition of the appropriate structure and the ratio is a measure of the strength and type of bonding. The ratio decreases with (a) increasing distance apart in the 4f series of the components, and (b) increasing average Group number.     

DSC study on simultaneous interpenetrating polymer network formation of epoxy resin and unsaturated polyester

A kinetic study on simultaneous interpenetrating polymer network formation of epoxy resin based on diglycidyl ether of Bisphenol A (DGEBA) and unsaturated polyester (UP) was performed by means of differential scanning calorimetry (DSC). Isothermal DSC characterizations of neat resins and their mixture (in a weight ratio of 50/50) were performed at different temperatures. Dynamic DSC characterization of the systems were performed at three different heating rates. A lower total heat of reaction developed during simultaneous polymerization in dynamic DSC tests was found, compared to the total heats developed during pure resins network formation. This phenomenon can be interpreted as an effect of network interlock that could not be compensated for completely by an increase in curing temperature. The kinetics of the reactions was described by empirical models. The DGEBA, in a 50/50 UP/DGEBA blend, indicated a higher rate constant than the pure DGEBA. The obtained results suggests that the hydroxyl end group of UP in the blend provided a favorably catalytic environment for the DGEBA cure. The results are in good agreement with the literature data. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2689–2698, 2002     

Liquefaction evaluation at a California substation site

A probabilistic seismic hazard analysis, in conjunction with subsurface geologic investigations, was used to evaluate the liquefaction potential of sand layers at Western Area Power Adminstration's Tracy, California, substation site. The seismic hazard analysis evaluates the peak ground acceleration corresponding to a lower level earthquake with a 50-percent probability of occurrence in 150 years, and two upper level earthquakes with a 10-percent probability of occurrence in 50 and 100 years. Based on the results of the geologic investigations and seismologic studies, it was concluded that the potential of liquefaction at the site for the design earthquakes was low     

A versatile leaky-wave antenna based on stub-loaded rectangularwaveguide .I. Theory

A new leaky-wave antenna is presented that possesses many desirable features and is suitable for application to both the millimeter-wave and microwave ranges. These desirable features, some of which are unusual, include a simple configuration, a wide flexibility in the range of available beamwidths, the ability to control the beamwidth and the direction of the beam essentially independently, and negligible cross polarization at all scan angles. The antenna structure consists of a parallel-plate stub guide of small height, less than a half wavelength, located off center on the top of rectangular waveguide. The beamwidth is easily controlled from very wide to very narrow by adjusting the stub width or location. The article presents the principle of operation and the theory, employing a new transverse equivalent network that is accurate, but also simple, so that it permits rapid and inexpensive numerical calculations