Optimization of decision rules for hydroelectric operation to reduce both eel mortality and unnecessary turbine shutdown: A search for a win–win solution

Worldwide populations of freshwater eels have declined with one of the contributing causes related to mortality during passage through hydropower turbines. An inherent trade‐off underlies turbine management where the competing demand for more hydropower comes at the expense of eel survival. A win–win solution exists when an option performs better on all competing demands compared to other options. A predictive model for eel migration based on a recent telemetry study was used to develop decision rules for turbine management in the Shenandoah River system. The performance of alternative decision rules was compared to the status quo policy to search for win–win solutions. Decision rules were defined by the probability of eel movement and were evaluated by the probabilities of false positive and false negative errors. The exact value of the cut‐off probability used in the decision rule will need to be determined through negotiation between stakeholders, but a range of cut‐off probabilities resulted in a win–win situation with both reduced eel mortality and increased turbine operation relative to the current shutdown strategy. Monitoring the implementation is needed to evaluate and update the predictive model and to refine the decision rule. Although the decision is framed for the Shenandoah River system, the analytical approach could be used to develop decision rules for turbine shutdown policy in other areas.     

SeaDoc: a self-adaptive document link provision system for framework extension tasks

It has been demonstrated that object-oriented frameworks can bring all kinds of advantages to application developers. To gain the advantages, application developers have to follow the framework-based development process. One step of the process is to integrate new components for framework extension. This is defined as a framework extension task in this work. In this task, application developers have to (1) retrieve examples, (2) acquire necessary documents, which are defined as the documents containing example adaptation information, and (3) adapt examples. Currently, acquiring necessary documents requires a lot of time because it is achieved through manually searching the Internet. Although there are many approaches to correctly acquiring those documents, the focus is never on time reduction. To satisfy the new criterion, we find the following challenging issues: (1) the dynamics of the valid document version, and (2) the uncertainty of the relevant necessary documents. The first issue is that the valid document version varies according to the framework version under which the retrieved example is workable. The second one is that the relevant necessary documents cannot be decided until a specific necessary document is specified. To resolve those two issues, a Self-adaptive Document link provision system, named SeaDoc, is provided in this work. SeaDoc resolves the dynamics by dynamically constructing document links with the corresponding valid document version. SeaDoc also resolves the uncertainty by adaptively selecting highly relevant document links. The experimental results show that SeaDoc reduces the time by 73 and 83 % compared with other two approaches.     

A holistic approach to protein structure alignment

A method of protein structure comparison developed previouslyis extended to incorporate other aspects of protein structurein addition to the inter-atomic vectors on which it was originallybased. Each additional aspect, which included hydrogen bonding,solvent exposure, torsional angles and sequence, was introducedseparately and evaluated for its ability to improve alignmentquality. The components were then combined, suitably weighted,to produce a more holistic comparison method. The method wastested on a group of remotely related ß/ type proteinsthat share a common feature in their overall chain fold. Theresults indicated that while the original inter-atomic vectorcomponent was sufficient to give the correct alignment of mostpairs of topologically equivalent proteins, the inclusion ofhydrogen bonds, torsion angles and a measure of solvent exposureled to improvements in the more difficult comparisons. Considerationof amino acid properties, including hydrophobicity, had no beneficialeffect. The failure of the latter component was not unexpectedconsidering the almost total lack of sequence similarity amongthe proteins considered.     

Feature extraction of the first difference of EMG time series for EMG pattern recognition

This paper demonstrates the utility of a differencing technique to transform surface EMG signals measured during both static and dynamic contractions such that they become more stationary. The technique was evaluated by three stationarity tests consisting of the variation of two statistical properties, i.e., mean and standard deviation, and the reverse arrangements test. As a result of the proposed technique, the first difference of EMG time series became more stationary compared to the original measured signal. Based on this finding, the performance of time-domain features extracted from raw and transformed EMG was investigated via an EMG classification problem (i.e., eight dynamic motions and four EMG channels) on data from 18 subjects. The results show that the classification accuracies of all features extracted from the transformed signals were higher than features extracted from the original signals for six different classifiers including quadratic discriminant analysis. On average, the proposed differencing technique improved classification accuracies by 2–8%.     

Vessel Inspection: A Micro-Aerial Vehicle-based Approach

Vessel maintenance entails periodic visual inspections of the internal and external parts of the hull in order to detect the typical defective situations affecting metallic structures, such as coating breakdown, corrosion, cracks, etc. The main goal of project MINOAS is the automation of the inspection process, currently undertaken by human surveyors, by means of a fleet of robotic agents. This paper overviews an approach to the inspection problem based on an autonomous Micro Aerial Vehicle (MAV) which, as part of this fleet, is in charge of regularly supplying images that can teleport the surveyor from a base station to the areas of the hull to be inspected. The control software approach adopted for the MAV is fully described, with a special emphasis on the self-localization capabilities of the vehicle. Experimental results showing the suitability of the platform to the application are as well reported and discussed.     

Influence of catalyst support geometry and wall thickness on NO x trap desulfation: rich/lean wobbling strategies and hexagonal cell supports for high SO2 selectivity during desulfation

Topics in Catalysis - This Synthetic Gas Bench (SGB) study focuses on the effect of cell geometry and wall thickness on the gasoline NO x trap functionality. The data show that besides a NO x trap...     

Responses of the Aphids Phorodon humuli and Rhopalosiphum padi to Sex Pheromone Stereochemistry in the Field

Gynoparous female and male damson-hop aphids, Phorodon humuli (Schrank), were caught in the field by water traps that were releasing the sex pheromone of this species, (1RS,4aR,7S,7aS)-nepetalactol. No behavioral activity was elicited by (4aS,7S,7aR)-nepetalactone, the major sex pheromone component of other aphid species such as Megoura viciae Buckton, even though olfactory cells were found in the secondary rhinaria on the third antennal segment of P. humuli that responded strongly to this compound. Gynoparous female P. humuli in the field responded less strongly to (1R,4aS,7S,7aR)-nepetalactol, the sex pheromone of the bird cherry-oat aphid, Rhopalosiphum padi (L.), than they did to the (4aR,7S,7aS)-nepetalactols, but males responded only to the latter. The (4aR,7S,7aS)-nepetalactone showed no electrophysiological activity so was not used in field trials. Releasing either the (4aS,7S,7aR)-nepetalactone or the (1R,4aS,7S,7aR)-nepetalactol with the (4aR,7S,7aS)-nepetalactols did not inhibit the response of P. humuli gynoparous females and males to the latter. Males of R. padi responded as strongly to the (4aR,7S,7aS)-nepetalactols as they did to (1R,4aS,7S,7aR)-nepetalactol. Males of P. humuli and R. padi responded positively to an increased concentration of the (4aR,7S,7aS)-nepetalactols released from two vials compared with that from a single vial, as did P. humuli (in one of two experiments) and R. padi to the (1RS,4aR,7S,7aS)- and (1R,4aS,7S,7aR)-nepetalactols when released together.     

The cholesterol-lowering effect of guar gum is not the result of a simple diversion of bile acids toward fecal excretion

The effects of partially hydrolyzed, nonviscous, guar gum (PHGG) on cholesterol metabolism and digestive balance have been compared with those of native guar gum (GUAR) in rats adapted to 0.4% cholesterol diets. Both types of guar gum elicited acidic fermentations in the large intestine, but only GUAR effectively lowered plasma cholesterol (P<0.001), chiefly in the triglyceride-rich lipoprotein fraction. The biliary bile acid excretion was significantly enhanced in rats fed GUAR (P<0.05), as well as the intestinal and cecal bile acid pool (P<0.001). In rats fed GUAR and to a lesser extent in those fed PHGG, the fecal excretion of bile acids and neutral sterol was higher than in controls (P<0.01). The digestive balance (cholesterol intake-steroid excretion) was positive in control rats (+47 μmol/d), whereas it was negative in rats fed GUAR (−20 μmol/d), which could involve a higher rate of endogenous cholesterol synthesis. In rats fed PHGG, the steroid balance remained slightly positive. Liver 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase activity was very low (22 pmol/min/mg protein), owing to cholesterol supplementation, in control rats or in rats fed PHGG, whereas it was markedly higher (+463%) in rats fed GUAR. In conclusion, even if PHGG does alter some parameters of the enterohepatic cycle of cholesterol and bile acids, its effects are not sufficient to elicit a significant cholesterol-lowering effect. The intestinal (ileal or cecal) reabsorption of bile acids was not reduced, but rather increased, by GUAR; nevertheless the intestinal capacities of reabsorption were overwhelmed by the enlargement of the digestive pool of bile acids. In the present model, induction of HMG-CoA reductase probably takes place in the presence of elevated portal bile acid concentrations.     

Controlled destruction of residual crosslinker in a silicone elastomer for drug delivery

In drug delivery systems that use silicone elastomers as a diffusion matrix for the active drug, it is common to crosslink the material by the hydrosilylation reaction. In this platinum‐catalyzed reaction, vinyl groups on a polymer add to the methyl siloxane hydride (MHS) groups on a low molecular mass crosslinker. With an excess of crosslinker, a fast curing is achieved and a fully crosslinked material is formed. Unreacted MHS groups were shown to remain in the elastomer after curing because of the excess crosslinker. In this work, a simple procedure was developed to eliminate the unreacted MHS groups from the final product. We found that storage of the product at +40°C and 75% relative humidity for a few weeks will effectively destroy the residual MHS groups in the elastomer. The effects of varying levels of humidity, oxygen, and temperature on this postcuring procedure were studied. The amount of MHS groups was measured with NMR and IR spectroscopy. We also found that the hardness of the material increased by approximately 25% as a consequence of this postcuring treatment. This increase is probably due to a secondary crosslinking reaction between MHS and silanol groups. Heat treatment at higher temperatures led to an even further increase in the hardness and compression modulus. Because no MHS groups remained in the elastomer when this heat treatment was started, it is apparent that another secondary crosslinking reaction is occurring, probably silanol condensation. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2254–2264, 2002     

Influence of the preparation conditions on the properties of gold catalysts for the oxidation of glucose

In this work, two deposition–precipitation methods for the preparation of gold catalysts for glucose oxidation were investigated. Thus far, gold colloids immobilized on carbon have been used for catalytic glucose oxidation, but the long-term stability of these systems was not sufficient. To improve the long-term stability we used the deposition–precipitation methods using NaOH (DP NaOH) or urea (DP urea) as precipitation agents as they were described by Haruta and Dekkers, respectively, using alumina as a support material. With these methods, it was possible to prepare highly active and selective catalysts which showed an excellent long-term stability. DP urea was found to be the preferred method, because in contrast to DP NaOH, no losses of gold occurred during the preparation, and it was possible to adjust various gold contents up to 10 wt% Au.