c is one of the most popular generally used languages of the 1980's. Its advantages are well known. In writing three books on the language, one of the authors has espoused many of its virtues without adequately co...
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c is one of the most popular generally used languages of the 1980's. Its advantages are well known. In writing three books on the language, one of the authors has espoused many of its virtues without adequately commenting on its vices. This paper will attempt to redress that balance.
In this study, the degradation performance of nutrients in zeolite trickling filter (ZTF) with different influent c/N ratios and aeration conditions was investigated. Microaeration was beneficial for enhancing NH4+-N ...
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In this study, the degradation performance of nutrients in zeolite trickling filter (ZTF) with different influent c/N ratios and aeration conditions was investigated. Microaeration was beneficial for enhancing NH4+-N removal performance. Due to the sufficient carbon source supply under a c/N ratio of 8, a high removal efficiency of NH4+-N and TN was simultaneously observed in ZTF. In addition, TN removal mainly occurred at the bottom, which might be explained by the sufficient nutrients available for bacteria to multiply in this zone. The abundant genera were Acinetobacter, Gemmobacter, Flavobacterium, and Pseudomonas, all of which are heterotrophic nitrification-aerobic denitrification (HNAD) bacteria. In addition, biofilm only slowed down the adsorption rate but did not significantly reduce the adsorption capacity of zeolite. Bio-zeolite had NH4+-N well adsorption capacity and bio-desorption capacity. Biological nitrogen removal performance was superior to physicochemical absorption of zeolite. The results suggested that the physicochemical of zeolite and biochemical reactions of microorganism coupling actions may be the main nitrogen transformation pathway in ZTF. Our research provides a reference for further understanding the nitrogen removal mechanism of zeolite bioreactors.
Small punch (SP) creep test specimen with an elliptical surface crack was suggested for use with creep crack growth testing. Estimation equations for fracture parameters are needed. K-equation was derived previously f...
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Small punch (SP) creep test specimen with an elliptical surface crack was suggested for use with creep crack growth testing. Estimation equations for fracture parameters are needed. K-equation was derived previously for the crack in the SP specimen. In this study, estimation equations for J and c* were derived. 3D elastic-plastic finite element analyses were carried out to determine J value along the front of the surface cracks of the same geometries as were employed for the K-estimation. The dimensionless function, h(1) was determined for various crack locations according to the EPRI scheme. The plastic limit load solution was also determined. The c*-equation of the cracked SP specimen was derived based on the J(p) solution using the analogy between the secondary creep constitutive law and the Ramberg-Osgood plasticity law. The c*-equation may be able to be used to characterize the creep crack growth behavior under the extensive creep condition of the cracked SP specimen.
In this study, c/c-Sic and c/c-Sic-Zrccomposites were prepared via chemical vapor infiltration and polymer infiltration pyrolysis, and the ablation mechanism under hypersonic oxygen-rich environmental conditions was ...
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In this study, c/c-Sic and c/c-Sic-Zrccomposites were prepared via chemical vapor infiltration and polymer infiltration pyrolysis, and the ablation mechanism under hypersonic oxygen-rich environmental conditions was investigated. The c/c-Siccomposites demonstrate an excellent ablation resistance in a hypersonic oxygen-rich environment with a relatively low temperature and speed of approximately 1800 K and 1100 m/s, respectively. It is only in the ablation center area with higher temperatures that a certain degree of thermochemical ablation was observed. The mass and linear ablation rates of c/c-Siccomposites (0.027 g/s and 0.117 mm/s, respectively) showed a significant increase in a hypersonic oxygen-rich environment with a temperature and velocity of approximately 2050 K and 2000 m/s, respectively. The high-temperature ablation resistance of Zrc-modified c/ c-Sic-Zrccomposites improved significantly. However, the Zrcceramiccomponent had a considerable impact on the ablation resistance of the material. The structural integrity of c/c-20Sic-30Zrccomposites was relatively high in hypersonic oxygen-rich environments with a jet temperature and velocity of 2050 K and 2000 m/s, respectively, and mass and linear ablation rates were 0.012 g/s and 0.015 mm/s, respectively. When the Zrccontent increased by 40%, the ablation resistance of the composite reduced significantly, whereas the mass and linear ablation rates increased to 0.043 g/s and 0.130 mm/s, respectively.
The effect of a seal device on the performance of aeroengines is obvious. As well as the complicated operating state of aeroengines also has important influence on seal device performance. Finger seal is a new seal de...
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The effect of a seal device on the performance of aeroengines is obvious. As well as the complicated operating state of aeroengines also has important influence on seal device performance. Finger seal is a new seal device, which has been extensively studied recently. However, so far there is little work about finger seal's dynamic performance considering work status. For this reason, finger seal's dynamic performance considering work status is proposed using equivalent dynamic model with distributed mass in this paper. The effects of the precession and nutation incline of rotor on the finger seal's performance are investigated. Meanwhile, density and preparation direction of fiber bundle have influence on its dynamic performance and that is studied under the rotor precession incline. Based on this, it is shown that the effect of rotor precession incline on the finger seal dynamic performance is obvious, thus it is necessary to consider the effect of the factor on finger seal dynamic performance. The present work is conducive to promote dynamic analysis technology of finger seal to engineering application, and also improve the theoretical research system and methodology of finger seal.
We report herein the exo-selective, regiospecific annulation of a wide range of functionalized aromatic substrates with 1,1-disubstituted alkenes through c(sp2)-H and benzylicc(sp3)-H activation by half-sandwich rare...
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We report herein the exo-selective, regiospecific annulation of a wide range of functionalized aromatic substrates with 1,1-disubstituted alkenes through c(sp2)-H and benzylicc(sp3)-H activation by half-sandwich rare-earth catalysts. This protocol offers a straightforward and atom-efficient route for the synthesis of a family of indane and tetralin derivatives bearing an all-carbon quaternary stereocenter that were difficult to access previously by other catalysts. The reaction mechanism has been elucidated by deuterium-labeling experiments and DFT calculations.
This paper discusses different aspects of an active flexible filament propulsion in a liquid medium. The immersed boundary method is used to model a flexible filament immersed in Newtonian fluid at low Reynolds number...
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This paper discusses different aspects of an active flexible filament propulsion in a liquid medium. The immersed boundary method is used to model a flexible filament immersed in Newtonian fluid at low Reynolds numbers. The flexible filament motion emulates that of a c. elegans. We varied some parameters of the filament motion, such as the interpolation points of the function related to the curvature of the filament and the upstroke and downstroke period, and analyzed the kinematic response in the body displacement and fluid flow. A methodology based on signal analysis is proposed for correct modeling of the movement of these filaments. The swimming velocity and distance are analyzed using wavelet transform, in which the notion of time-frequency localization is made precise. This methodology allows defining which parameters lead to the best efficiency, e.g., greater swim distance for the same number of strokes, making it very valuable for passive control of the filament.
Aims The goal of this study was to examine, for the first time, the virulence and pathogenicity of aerosolized Burkholderia pseudomallei, strain NcTc 13392, in BALB/c mice in order to develop an animal model for testi...
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Aims The goal of this study was to examine, for the first time, the virulence and pathogenicity of aerosolized Burkholderia pseudomallei, strain NcTc 13392, in BALB/c mice in order to develop an animal model for testing novel medical countermeasures (McMs) for the treatment of human acute and subacute (a disease state between acute and chronic) melioidosis. Methods and Results BALB/c mice were exposed to varying doses of aerosolized bacteria. Acute disease was seen in animals exposed to a very-high dose (>= 10(3) cFU per animal) and death occurred 3-4 days postchallenge (pc). Bacteria were detected in the lungs, liver, kidney and spleen. In contrast, animals exposed to a low dose (<10 cFU per animal) survived to the end of the study (day 30 pc) but developed weight loss, a bacterial tissue burden and increasing clinical signs of infection from day 20 pc onwards, mimicking a subacute form of the disease. Pathological changes in the tissues mirrored these findings. conclusions This proof of concept study has shown that B. pseudomallei strain NcTc 13392 is virulent and pathogenic in BALB/c mice, when delivered by aerosol. By varying the doses of aerosolized bacteria it was possible to mimiccharacteristics of both human acute and subacute melioidosis, at the same time, within the same study. Significance and Impact of the Study Burkholderia pseudomallei, the aetiological agent of melioidosis, causes a serious and often fatal disease in humans and animals. Novel McMs are urgently needed for both public health and biodefense purposes. The present model provides a useful tool for the assessment and evaluation of new McMs (e.g. therapeutics and vaccines) and offers the potential for testing new treatments for both subacute to chronic and acute melioidosis prior to human clinical trials.
Iron single atom catalysts (FeN4) hosted in the micropores of N-doped carbons offer excellent performance for the oxygen reduction reaction (ORR). Achieving a high density of FeN4 sites accessible for ORR has proved c...
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Iron single atom catalysts (FeN4) hosted in the micropores of N-doped carbons offer excellent performance for the oxygen reduction reaction (ORR). Achieving a high density of FeN4 sites accessible for ORR has proved challenging to date. Herein, a simple surface Nacl-assisted method towards microporous N-doped carbon electrocatalysts with an abundance of catalytically accessible FeN4 sites is reported. Powder mixtures of microporous zeolitic imidazolate framework-8 and Nacl are first heated to 1000 degrees c in N-2, with the melting of Nacl above 800 degrees ccreating a highly porous N-doped carbon product (Nc-Nacl). Ferric (Fe3+) ions are then adsorbed onto Nc-Nacl, with a second pyrolysis stage at 900 degrees c in N-2 yielding a porous Fe/Nc-Nacl electrocatalyst (Brunauer-Emmett-Teller surface area, 1911 m(2) g(-1)) with an excellent dispersion and high density of accessible surface FeN4 sites (26.3 x 10(19) sites g(-1)). The Fe/Nc-Nacl electrocatalyst exhibits outstanding ORR performance with a high half-wave potential of 0.832 V (vs reversible hydrogen electrode) in 0.1 m HclO4. When used as the ORR cathode catalyst in a 1.0 bar H-2-O-2 fuel cell, Fe/Nc-Nacl offers a high peak power density of 0.89 W cm(-2), ranking it as one of the most active M-N-c materials reported to date.
We investigated the field emission of graphdiyne-c-60 nanocomposite by using first principle calculation. The results show that graphdiyne obtains good electrical performances such as high level of emission currents. ...
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We investigated the field emission of graphdiyne-c-60 nanocomposite by using first principle calculation. The results show that graphdiyne obtains good electrical performances such as high level of emission currents. The construction with c-60 cluster and graphdiyne can take full advantages of the curvature effect and the tip effect of c-60 cluster which induces local charge improvement. It shows that the c-60 cluster can strengthen the field emission of graphdiyne-c-60 nanocomposite. It implies that the graphdiyne-c-60 nanofabrication could have a potential application for field emission electron sources in the future.
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