1,037 research outputs found

    Meteorological utility of high resolution multi-spectral data

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    There are no author-identified significant results in this report

    Performance of cylindrical converters with preferred-crystal-orientation emitters of chemically vapor deposited tungsten

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    Design and evaluation of cylindrical out-of-pile thermionic converter test vehicle to determine performance of tungsten emitters with preferred crystal orientatio

    Entropy-scaling search of massive biological data

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    Many datasets exhibit a well-defined structure that can be exploited to design faster search tools, but it is not always clear when such acceleration is possible. Here, we introduce a framework for similarity search based on characterizing a dataset's entropy and fractal dimension. We prove that searching scales in time with metric entropy (number of covering hyperspheres), if the fractal dimension of the dataset is low, and scales in space with the sum of metric entropy and information-theoretic entropy (randomness of the data). Using these ideas, we present accelerated versions of standard tools, with no loss in specificity and little loss in sensitivity, for use in three domains---high-throughput drug screening (Ammolite, 150x speedup), metagenomics (MICA, 3.5x speedup of DIAMOND [3,700x BLASTX]), and protein structure search (esFragBag, 10x speedup of FragBag). Our framework can be used to achieve "compressive omics," and the general theory can be readily applied to data science problems outside of biology.Comment: Including supplement: 41 pages, 6 figures, 4 tables, 1 bo

    Self-excited Oscillations of Charge-Spin Accumulation Due to Single-electron Tunneling

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    We theoretically study electronic transport through a layer of quantum dots connecting two metallic leads. By the inclusion of an inductor in series with the junction, we show that steady electronic transport in such a system may be unstable with respect to temporal oscillations caused by an interplay between the Coulomb blockade of tunneling and spin accumulation in the dots. When this instability occurs, a new stable regime is reached, where the average spin and charge in the dots oscillate periodically in time. The frequency of these oscillations is typically of the order of 1GHz for realistic values of the junction parameters

    Promising Developments in Bio-Based Products as Alternatives to Conventional Plastics to Enable Circular Economy in Ukraine

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    Transforming the plastic industry toward producing more sustainable alternatives than conventional plastics, as an essential enabler of the bio-based circular economy (CE), requires reinforcing initiatives to drive solutions from the lab to the market. In this regard, startups and ideation and innovation events can potentially play significant roles in consolidating efforts and investments by academia and industry to foster bio-based and biodegradable plastic-related developments. This study aimed to present the current trends and challenges of bioplastics and bio-based materials as sustainable alternatives for plastics. On this basis, having conducted a systematic literature review, the seminal research themes of the bio-based materials and bioplastics literature were unfolded and discussed. Then, the most recent developments of bio-based sustainable products in Ukraine, as alternatives to petroleum-based plastics, that have gained publicity through local startup programs and hackathons were presented. The findings shed light on the potential of the bio-based sector to facilitate the CE transition through (i) rendering innovative solutions most of which have been less noticed in academia before; (ii) enhancing academic debate and bridging the gap between developers, scholars, and practitioners within the plastic industry toward creating circularity across the supply chain; (iii) identifying the main challenges and future perspectives for further investigations in the future

    The effect of paper waste and food waste on biohydrogen production at mesophilic temperatures in batch reactors

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    Bio-hydrogen production in an EGSB reactor under mesophilic, thermophilic and hyperthermophilic conditions

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    Mesophilic, thermophilic and hyperthermophilic bio-hydrogen production with an expanded granular sludge blanket (EGSB) fed with glucose and arabinose, without methane production, was demonstrated. Homoacetogenesis was observed on reactor when operated under mesophilic (37ºC) conditions but not under thermophilic (55ºC) and hyper-thermophilic conditions (70ºC). It was also found that under thermophilic and hyper-thermophilic conditions glucose is preferentially consumed than arabinose.Fundação para a Ciência e a Tecnologia (FCT) - SFRH/BD/29823/2006, SFRH/BPD/24221/2005, POCI/ENR/57786/2004

    Effect of arabinose concentration on dark fermentation hydrogen production using different mixed cultures

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    Dark fermentation hydrogen production from arabinose at concentrations ranging between 0 and 100 g/L was examined in batch assays for three different mixed anaerobic cultures, two suspended sludges (S1, S2) obtained from two different sludge digesters and one granular sludge (G) obtained from a brewery wastewater treatment plant. After elimination of the methanogenic activity by heat treatment, all mixed cultures produced hydrogen, and optimal hydrogen rates and yields were generally observed for concentrations between 10 and 40 g/L of substrate. Higher concentrations of arabinose up to 100 g/L inhibited hydrogen production, although the effect was different from inoculum to inoculum. It was evident that the granular biomass was less affected by increased initial arabinose concentrations when calculating the rate of decrease in hydrogen yields versus arabinose concentrations, compared against the two suspended sludges. The largest amount of soluble microbial product produced for all three inocula was for n-butyrate. Also, valeric acid production was observed in some samples.Fundação para a Ciência e a Tecnologia (FCT
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