2,093 research outputs found

    Modeling the Effects of Distribution System Topology on Water Quality

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    Inadequate treatment of drinking water causes the formation of disinfection by-products and the regrowth of harmful microbial species. Various studies have addressed the problem of water quality monitoring, but very few have employed topological analysis, a valuable mathematical tool widely applied in biological, business, and social research. This thesis examines the relationship between the topological properties of water distribution systems and water-quality models. In particular, the research proposes a novel framework for mapping network topological attributes to water-quality models. This research adopts topological metrics to assess the accuracy of the predictions of chlorine concentrations in dead ends. It examines four fundamental water-quality models: advection, advection-dispersion, bulk-advection, and bulk-advection-dispersion. The results show the bulk-advection-dispersion model has larger root mean square errors in networks with a grid structure, and that topological metrics are generally correlated with water-quality models, although more studies are required to develop this correlation in detail

    Effects of orthographic consistency and homophone density on Chinese spoken word recognition

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    Studies of alphabetic language have shown that orthographic knowledge influences phonological processing during spoken word recognition. This study utilized the Event-Related Potentials (ERPs) to differentiate two types of phonology-to-orthography (P-to-O) mapping consistencies in Chinese, namely homophone density and orthographic consistency. The ERP data revealed an orthographic consistency effect in the frontal-centrally distributed N400, and a homophone density effect in central-posteriorly distributed late positive component (LPC). Further source analyses using the standardized low-resolution electromagnetic tomography (sLORETA) demonstrated that the orthographic effect was not only localized in the frontal and temporal-parietal regions for phonological processing, but also in the posterior visual cortex for orthographic processing, while the homophone density effect was found in middle temporal gyrus for lexical-semantic selection, and in the temporal-occipital junction for orthographic processing. These results suggest that orthographic information not only shapes the nature of phonological representations, but may also be activated during on-line spoken word recognition

    The feedback consistency effect in Chinese character recognition:evidence from a psycholinguistic norm

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    Researchers have demonstrated the importance of phonology in literacy acquisition and in visual word recognition. For example, the spelling-to-sound consistency effect has been observed in visual word recognition tasks, in which the naming responses are faster and more accurate for words with the same letters that also have the same pronunciation (e.g. -ean is always pronounced /in/, as in lean, dean, and bean). In addition, some studies have reported a much less intuitive feedback consistency effect when a rime can be spelled in different ways (e.g. /ip/ in heap and deep) in lexical decision tasks. Such findings suggest that, with activation flowing back and forth between orthographic and phonological units during word processing, any inconsistency in the mappings between orthography and phonology should weaken the stability of the feedback loop, and, thus, should delay recognition. However, several studies have failed to show reliable feedback consistency in printed word recognition. One possible reason for this is that the feedback consistency is naturally confounded with many other variables, such as orthographic neighborhood or bigram frequency, as these variables are difficult to tease apart. Furthermore, there are challenges in designing factorial experiments that perfectly balance lexical stimuli on all factors besides feedback consistency. This study aims to examine the feedback consistency effect in reading Chinese characters by using a normative data of 3,423 Chinese phonograms. We collected the lexical decision time from 180 college students. A linear mixed model analysis was used to examine the feedback consistency effect by taking into account additional properties that may be confounded with feedback consistency, including character frequency, number of strokes, phonetic combinability, semantic combinability, semantic ambiguity, phonetic consistency, noun-to-verb ratios, and morphological boundedness. Some typical effects were observed, such as the more frequent and familiar a character, the faster one can decide it is a real character. More importantly, the linear mixed model analysis revealed a significant feedback consistency effect while controlling for other factors, which indicated that the pronunciation of phonograms might accommodate the organization of Chinese orthographic representation. Our study disentangled the feedback consistency from the many other factors, and supports the view that phonological activation would reverberate to orthographic representation in visual word recognition

    Preparation and Characterization of Carrot Nanocellulose and Ethylene/Vinyl Acetate Copolymer-Based Green Composites

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    This study aims to investigate the effect of nanocellulose on the properties and physical foaming of ethylene/vinyl acetate (EVA) copolymer. The nanocellulose is prepared from waste carrot residue using the 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) oxidation method (CT) and is further modified through suspension polymerization of methyl methacrylate (MMA) monomer (CM). The obtained nanocellulose samples (CT or CM) are added to EVA to create a series of nanocomposites. Moreover, the EVA and CM/EVA composite were further foamed using supercritical carbon dioxide physical foaming. TEM results show that the average diameters of CT and CM are 24.35 ± 3.15 nm and 30.45 ± 1.86 nm, respectively. The analysis of mechanical properties demonstrated that the tensile strength of pure EVA increased from 10.02 MPa to 13.01 MPa with the addition of only 0.2 wt% of CM. Furthermore, the addition of CM to EVA enhanced the melt strength of the polymer, leading to improvements in the physical foaming properties of the material. The results demonstrate that the pore size of the CM/EVA foam material is smaller than that of pure EVA foam. Additionally, the cell density of the CM/EVA foam material can reach 3.23 × 1011 cells/cm3

    The Individual and Combined Effects of Deoxynivalenol and Aflatoxin B1 on Primary Hepatocytes of Cyprinus Carpio

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    Aflatoxin B1 (AFB1) and deoxynivalenol (DON) are important food-borne mycotoxins that have been implicated in animal and human health. In this study, individual and combinative effects of AFB1 and DON were tested in primary hepatocytes of Cyprinus carpio. The results indicated that the combinative effects of AFB1 and DON (0.01 μg/mL AFB1 and 0.25 μg/mL DON; 0.02 μg/mL AFB1 and 0.25 μg/mL DON; 0.02 μg/mL AFB1 and 0.5 μg/mL DON) were higher than that of individual mycotoxin (P < 0.05). The activity of AST, ALT and LDH in cell supernatant was higher than that of control group (P < 0.05) when the mycotoxins were exposed to primary hepatocytes for 4 h. The decreased cell number was observed in tested group by inverted light microscopy. The mitochondrial swelling, endoplasmic reticulum dilation and a lot of lipid droplets were observed in primary hepatocytes by transmission electron microscope. Therefore, this combination was classified as an additive response of the two mycotoxins

    Decay Widths of Excited Heavy Mesons From QCD Sum Rules at the Leading Order of HQET

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    The widths for pionic decays of lowest two excited doublets (0^+,1^+) and (1^+,2^+) of heavy mesons are studied with QCD sum rules in the leading order of heavy quark effective theory. The ambiguity due to presence of two distinct 1^+ states are solved. The soft pion approximation is not used.Comment: RevTeX, 16 pages including 1 figure; minor changes, final version to appear in Physical Review

    Characterization of transparent conductive delafossite-CuCr 1−x O 2 films

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    a b s t r a c t In this study, the CuCr 1−x O 2 films with x = 0.00-0.25 were prepared on a quartz substrate by sol-gel processing. The films were first deposited onto a quartz substrate by spin-coating. The specimens were annealed at 500 • C in air for 1 h and post-annealed in N 2 at 700 • C for 2 h. As the films were post-annealed in N 2 , a pure delafossite-CuCrO 2 phase appeared in the CuCr 1−x O 2 films below x = 0.20. However, an additional CuO phase appeared at x = 0.25. The pure delafossite-CuCrO 2 phase can exist within x ≤ 0.20 in CuCr 1−x O 2 films. The binding energies of Cu-2p 3/2 and Cr-2p 3/2 in the CuCr 1−x O 2 films with the pure delafossite-CuCrO 2 phase were 932.1 ± 0.2 eV and 576.0 ± 0.2 eV, respectively. The surface exhibited elongated grain features when the pure delafossite-CuCrO 2 phase was present in the CuCr 1−x O 2 films. The maximum transmittance of the CuCr 1−x O 2 films with the pure delafossite-CuCrO 2 phase was approximately 80%, which moved toward the visible region with the increasing x-value. The film absorption edges were observed at 400 nm, which were sharper with the increasing x-value. The optical bandgaps of CuCr 1−x O 2 films with the pure delafossite-CuCrO 2 phase were approximately 3.0 eV. The electrical conductivity of CuCr 1−x O 2 films with the pure delafossite-CuCrO 2 phase was 1.1 × 10 −3 S cm −1 (x = 0.00), and increased to 0.16 S cm −1 (x = 0.20). The corresponding carrier concentration of CuCr 1−x O 2 films with the pure delafossite-CuCrO 2 phase was 2.8 × 10 14 cm −3 (x = 0.00), and markedly increased to 1.8 × 10 16 cm −3 (x = 0.20). The Cr-deficient condition in delafossite-CuCrO 2 films enhances film electrical conductivity and carrier concentration, but retains the film&apos;s high-visible transparency
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