A side‐by‐side comparison of CPV module and system performance

A side‐by‐side comparison is made between concentrator photovoltaic module and system direct current aperture efficiency data with a focus on quantifying system performance losses. The individual losses measured/calculated, when combined, are in good agreement with the total loss seen between the module and the system. Results indicate that for the given test period, the largest individual loss of 3.7% relative is due to the baseline performance difference between the individual module and the average for the 200 modules in the system. A basic empirical model is derived based on module spectral performance data and the tabulated losses between the module and the system. The model predicts instantaneous system direct current aperture efficiency with a root mean square error of 2.3% relative. Copyright © 2016 John Wiley & Sons, Ltd.     

Electronic Transport via Proteins

A central vision in molecular electronics is the creation of devices with functional molecular components that may provide unique properties. Proteins are attractive candidates for this purpose, as they have specific physical (optical, electrical) and chemical (selective binding, self‐assembly) functions and offer a myriad of possibilities for (bio‐)chemical modification. This Progress Report focuses on proteins as potential building components for future bioelectronic devices as they are quite efficient electronic conductors, compared with saturated organic molecules. The report addresses several questions: how general is this behavior; how does protein conduction compare with that of saturated and conjugated molecules; and what mechanisms enable efficient conduction across these large molecules? To answer these questions results of nanometer‐scale and macroscopic electronic transport measurements across a range of organic molecules and proteins are compiled and analyzed, from single/few molecules to large molecular ensembles, and the influence of measurement methods on the results is considered. Generalizing, it is found that proteins conduct better than saturated molecules, and somewhat poorer than conjugated molecules. Significantly, the presence of cofactors (redox‐active or conjugated) in the protein enhances their conduction, but without an obvious advantage for natural electron transfer proteins. Most likely, the conduction mechanisms are hopping (at higher temperatures) and tunneling (below ca. 150–200 K).     

High Nitrification Rate at Low pH in a Fluidized Bed Reactor with either Chalk or Sintered Glass as the Biofilm Carrier

A nitrification process using a fluidized bed reactor with chalk (solid calcium carbonate) as the biomass carrier and the only buffer agent was studied. The pH established in the reactor varied between 4.5 to 5.5, with lower pH obtained at higher nitrification rates. In spite of the low pH, high rate nitrification was observed with the nitrification kinetic parameters in the chalk reactor similar to those of biological reactors operating at pH > 7. Results from microsensor measurements refuted the possibility that favorable pH micro-conditions prevailed on the chalk particles and contributed to high reactor performance. In addition, identification of the major bacterial species in the low pH chalk reactors revealed well-known nitrifying bacteria. Based on these results, the performance of a fluidized bed reactor with porous sintered glass particles as the carrier for the biofilm (instead of chalk particles) was tested at similar low pH for comparison purposes. In contrast to the common knowledge of the nitrifers high sensitivity to low pH, the results from the non-chalk biofilm reactor showed that well-known nitrifying bacteria have the ability to nitrify at a high rate at low pH in a biofilm reactor using an inert (sintered glass) carrier.     

Spatial Mapping of Morphology and Electronic Properties of Air‐Printed Pentacene Thin Films

To accelerate the pace of materials discovery and application, comprehensive links need to be established between a material's structure, properties, and process conditions used to obtain the material and/or final application format. This work examines the dry printing of pentacene thin film transistor (TFT) channels by guard flow‐enhanced organic vapor jet printing (GF‐OVJP), a technique that enables direct, solvent‐free, additive patterning of device‐quality molecular semiconductors in air. Deposition in air entails non‐trivial effects at the boundary between ambient surroundings and the gas jet carrying the semiconductor vapor that influence the morphology and properties of the resulting electronic devices. Synchrotron X‐ray diffraction is employed, complemented by measurement of electronic properties of GF‐OVJP deposited films in a TFT to reveal how the morphology and electronic properties of the films depend on thickness, location within the printed pattern, nozzle translation velocity, and other process parameters. The hole field‐effect mobility of the printed pentacene film is linked quantitatively with its crystallinity, as well as with extent of exposure to ambient air during deposition. The analysis can be extended to accurately predict the performance of devices deposited in air by GF‐OVJP, which are demonstrated here for a planar, large area deposit.     

Realization of temporal linear transformations by the use of a spatial-diffraction-based optical system

Signal processing in general, and optical signal processing in particular, make extensive use of linear transformations. The temporal nature of many optical signals (e.g., in optical communication systems) makes the realization of temporal transformations a desired extension. We present a system making possible the realization of arbitrary temporal linear transformation. The system supports real-time changes of the realized transformation. The mathematical analysis is derived, and computer simulations are presented.     

Finding the best compromise in compiling compound loops to Verilog

In this work we consider a special optimization problem involved with compiling compound loops (combining nested and consecutive sub-loops) to Verilog. Each sub-loop of the compound loop may require a different optimized hardware configuration (OHC) for optimized execution times. For example, one loop requires at least two memory ports and one multiplier for an optimized execution time, while another loop may require only one memory port but two multipliers, yet one OHC should be selected for both loops. The goal is to compute a minimal OHC which, based on the different heat levels (expected number of iterations) of the sub-loops, is a good compromise between all the conflicting requirements of each sub-loop. Though synthesis of nested loops has been implemented in quite a few systems this aspect has not been considered so far. We avoid the use of time consuming integer linear programming (ILP) techniques and instead use a fast space exploration technique combined with an efficient variant of list scheduling.Another novel aspect of the proposed system is the observation that the real latencies of the hardware units should be considered as variables of the OHC rather than fixed real values as is usually done in high-level synthesis systems. Experimental results show a significant improvement in the OHC without a significant increase in the execution time due to the use of this search procedure.¹     

Direct gas chromatographic determination of the two isomeric insecticides, aldicarb and butocarboxime and their toxic metabolites: Application to residue analysis in crops and leaves

Summary A gas-chromatographic method is described for determination of residues of butocarboxime (Drawin), its structural isomer aldicarb (Temik), and their toxic sulfoxide and sulfone metabolites. These compounds were determined intact, by gaschromatography employing a thermionic specific detector (TSD). Breakdown of these relatively thermally unstable compounds was avoided by lowering the inlet temperature to 150 °C, by keeping column temperature as low as possible, and by using a low-load liquid phase (2% of OV-17 on Gas-Chrom Q). These compounds were determined in enriched extracts of samples of tomatoes and apples and also in the leaves of citrus and cotton. The method is suitable for the separation, differentiation and determination of the two isomers and their metabolites at an enrichment level of 0.1 g/g of fresh weight. The results were confirmed by gas chromatography — chemical-ionization mass-spectrometry.

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Direkte gaschromatographische Bestimmung zweier isomerer Insecticide Aldicarb und Butocarboxim und ihrer Metabolite: Anwendung auf die Rückstandsanalyse von Feldfrüchten und Blätter

Zusammenfassung Es wird eine gaschromatographische Rückstandsbestimmung des Butocarboxim, sein strukturell isomeres Aldicarb (Temik) und ihrer toxischen Sulfoxide und Sulfon-Metaboliten beschrieben. Diese Verbindungen wurden gaschromatisch unter Anwendung eines Thermoionen-Detektors bestimmt (TSD). Die Zerstörung dieser thermisch relativ unstabilen Verbindung wurde durch Erniedrigung der Einlaßtemperatur von 150 °C vermieden, indem die Säulentemperatur so niedrig als möglich gehalten wurde und durch Anwendung einer gering beladenen Säule (2% OV-17 auf Gas-Chrom Q). Diese Verbindungen wurden in angereicherten Extrakten von Tomaten und Äpfeln und ebenso in den Blättern von Citrus und Baumwolle bestimmt. Die Methode ist brauchbar für die Abtrennung, Differenzierung und Bestimmung der beiden Isomere und deren Metabolite bei einer Anreicherung in der Probe auf 0,1 g/g des Frischgewichtes. Die Resultate werden durch Gaschromatographie und Ionisation-Massenspektrometrie bestätigt.

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Contribution from the Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel. No. 644-E