232 research outputs found

    Direct Numerical Simulation Of Turbulent Multispecies Channel Flow With Wall Ablation

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    The design of solid rocket motors requires the prediction of changes induced by the ablation process occurring at the nozzle throat. The present study aims at understand-ing the effects of ablation on the turbulent boundary layer performing direct numerical simulations in a channel flow configuration. An ablation boundary condition for arbitrary chemical composition and pyrolysis scheme is developed and presented in this paper. Then, two DNS of a seven species reacting flow are performed: a) with inert walls; b) with ablated walls. Generated data are compared and analyzed looking at first order statistics. It is shown that the classical law of the wall for velocity and temperature are not appropriate to represent the numerical result. The chemical equilibrium assumption is shown to be valid in the inert case and a wall function consistent with this assumption is in fair agreement with the results. Nomenclature m ̇ wall mass flux, kg · m−2 · s−1 ṙc carbon surface recession rate, m/s ṡk surface production rate of k, kg · m−2 · s−

    Do mutual funds have consistency in their performance?

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    Using a comprehensive data set of 714 Chinese mutual funds from 2004 to 2015, the study investigates these funds’ performance persistence by using the Capital Asset Pricing model, the Fama-French three-factor model and the Carhart Four-factor model. For persistence analysis, we categorize mutual funds into eight octiles based on their one year lagged performance and then observe their performance for the subsequent 12 months. We also apply Cross-Product Ratio technique to assess the performance persistence in these Chinese funds. The study finds no significant evidence of persis- tence in the performance of the mutual funds. Winner (loser) funds do not continue to be winner (loser) funds in the subsequent time period. These findings suggest that future performance of funds cannot be predicted based on their past performance.info:eu-repo/semantics/publishedVersio

    A spatially-VSL gravity model with 1-PN limit of GRT

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    A scalar gravity model is developed according the 'geometric conventionalist' approach introduced by Poincare (Einstein 1921, Poincare 1905, Reichenbach 1957, Gruenbaum1973). In principle this approach allows an alternative interpretation and formulation of General Relativity Theory (GRT), with distinct i) physical congruence standard, and ii) gravitation dynamics according Hamilton-Lagrange mechanics, while iii) retaining empirical indistinguishability with GRT. In this scalar model the congruence standards have been expressed as gravitationally modified Lorentz Transformations (Broekaert 2002). The first type of these transformations relate quantities observed by gravitationally 'affected' (natural geometry) and 'unaffected' (coordinate geometry) observers and explicitly reveal a spatially variable speed of light (VSL). The second type shunts the unaffected perspective and relates affected observers, recovering i) the invariance of the locally observed velocity of light, and ii) the local Minkowski metric (Broekaert 2003). In the case of a static gravitation field the model retrieves the phenomenology implied by the Schwarzschild metric. The case with proper source kinematics is now described by introduction of a 'sweep velocity' field w: The model then provides a hamiltonian description for particles and photons in full accordance with the first Post-Newtonian approximation of GRT (Weinberg 1972, Will 1993).Comment: v1: 11 pages, GR17 conf. paper, Dublin 2004, v2: WEP issue solved, section on acceleration transformation added, text improved, more references, same results, v3: typos removed, footnotes, added and references updated, v4: appendix added, improved tex

    Erythropoietin overrides the triggering effect of DNA platination products in a mouse model of Cisplatin-induced neuropathy

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    <p>Abstract</p> <p>Background</p> <p>Cisplatin mediates its antineoplastic activity by formation of distinct DNA intrastrand cross links. The clinical efficacy and desirable dose escalations of cisplatin are restricted by the accumulation of DNA lesions in dorsal root ganglion (DRG) cells leading to sensory polyneuropathy (PNP). We investigated in a mouse model by which mechanism recombinant erythropoietin (rhEPO) protects the peripheral nervous system from structural and functional damage caused by cisplatin treatment with special emphasis on DNA damage burden.</p> <p>Results</p> <p>A cumulative dose of 16 mg cisplatin/kg resulted in clear electrophysiological signs of neuropathy, which were significantly attenuated by concomitant erythropoietin (cisplatin 32,48 m/s ± 1,68 m/s; cisplatin + rhEPO 49,66 m/s ± 1,26 m/s; control 55,01 m/s ± 1,88 m/s; p < 0,001). The co-application of rhEPO, however, did not alter the level of unrepaired cisplatin-DNA lesions accumulating in DRG target cells. Micro-morphological analyses of the sciatic nerve from cisplatin-exposed mice showed damaged myelin sheaths and mitochondria. Co-administered rhEPO inhibited myelin sheaths from structural injuries and resulted in an increased number of intact mitochondria.</p> <p>Conclusion</p> <p>The protective effect of recombinant erythropoietin is not mediated by reducing the burden of DNA platination in the target cells, but it is likely to be due to a higher resistance of the target cells to the adverse effect of DNA damage. The increased frequency of intact mitochondria might also contribute to this protective role.</p

    Bioformulation of microbial biocontrol agents for a sustainable agriculture

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    The application of microbial based biopesticides has become a sustainable alternative to the use of chemicals to prevent yield losses due to plant pathogens. However, microbial based biopesticides are often unsuccessfully formulated and do not meet the demanding regulatory standards required by the agencies, which hinders their commercialization. Hence, an outline on the approaches to attain more effective formulations might be useful for the development of future more effective products. With this aim, this chapter reports the current state of biocontrol strategies and describes the principles of microbial biocontrol formulations. Emphasis is placed on techniques and tools available for the development and characterisation of microbial products. To provide glimpses on the possible formulations, the different existing additives, carriers, inoculation techniques and formulation types are exhaustively reviewed. Finally, requirements and principles for efficacy evaluation of plant protection products in the European Union are include
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