2,204 research outputs found

    An Advanced Engineering Framework experimented on a R&AE Electric Vehicle case

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    International audienceThis article describes modeling activity experimented on an Advanced engineering case of Zero Emission Vehicles at Renault. A key advantage of our approach is that system architecture and requirements management at all the stages of the system life cycle are managed in a unique data model and unique database. It reviews conceptualization and production process of a complex system. It presents a spectrum of activity modeling techniques, ranging from a widely used systems engineering diagram, to continuous flow modeling. The techniques include use case definition, requirements elicitation, system architecture definition and finally Electric and Electronic architecture. The article also describes refinements of modeling activity using arKItect© tool

    Electrostatic potentials and average electron densities of bioisosteres in methylsquarate and acetic acid

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    © 2016 Future Science Ltd. Background: The bioisosterism in -CO2H and -C4HO3 is exploited using the quantum theory of atoms in molecules and molecular electrostatic potentials (ESP). Results & discussion: Bioisosteres in methylsquarate and acetic acid, in the neutral/anionic forms, have average electron densities that differ by less than 2% (i.e., ∼0.01 atomic units) while irrespective of the capping group. The topography of the ESP reveals similarities in the case of the neutral species but not in the anionic forms. Conclusion: The nonclassical bioisosteres in methylsquarate and acetic acid have average electron densities that are similar and relatively insensitive to the ionization state (neutral or anionic) or its studied capping group (H, CH3, Cl or phenyl). The ESP reveals similarities in the topography of neutral molecules

    Adenine-thymine tautomerization under the influence of strong homogeneous electric fields

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    © the Owner Societies 2018. The effect of strong electric fields on the tautomerization of the adenine-thymine (AT) base pair in DNA is explored using density functional theory. It was found that the AT base pair is not likely to undergo a double proton transfer reaction even in the presence of electric fields ranging from 5.14 × 108 to 5.14 × 109 V m-1. This conclusion holds true in Gibbs energies computed at 25 °C or 37 °C. Energy correction terms to the electronic energy, such as total internal energy, Gibbs energy, zero-point energy, enthalpy and entropy corrections, were investigated in detail to pinpoint the major contributors to the low probability of the AT tautomerization. It was found that the entropy corrections are the least significant, while zero-point energy and Gibbs energy corrections can be large enough to thermodynamically inhibit the DPT in AT

    Effects of Intense Electric Fields on the Double Proton Transfer in the Watson-Crick Guanine-Cytosine Base Pair

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    Copyright © 2018 American Chemical Society. The double proton transfer reaction in the guanine-cytosine (GC) base pair is studied, using density functional theory, to understand the chances of mutations under the effect of uniform electric fields in the order of 108 to 109 V m-1. On the basis of potential energy surfaces, reaction Gibbs energies, equilibrium constants, imaginary frequencies, forward and reverse barrier heights, tunneling-corrected rate constants, half-lives of the forward and reverse reactions, percent tautomerization, and Boltzmann distributions, it was found that fields ≥+3.60 × 109 V m-1 facilitate the mutation in the GC base pair and reduce the rectification of point mutations. Fields applied along the double proton transfer in the -x (defined in the C to G direction) direction favor the canonical over the rare tautomers. Tunneling-corrected rate constants of the forward reaction increase exponentially with stronger fields in the -x direction and follow a Gaussian curve for the reverse reaction

    Experimental test on an RC beam equipped with embedded barometric pressure sensors for strains measurement

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    The current trend in structural health monitoring (SHM) is to install increasingly large numbers of distributed, heterogeneous types of sensors, for a timely and exhaustive detection of any possible damage scenario evolving in the system. These sensors should be low-cost, easy to install, robust and durable. Among others, strain remains one of the most straightforward measurands for monitoring the state of a structural element and for assessing its health condition. However, for application to reinforced concrete structures, currently available strain sensing devices, such as electric strain gauges or fibre optic sensors, do not fully satisfy the aforementioned requirements, generally proving difficult to install, fragile and expensive. In this paper, an innovative monitoring technology, called Smart Steel System (S3), is proposed that measures strains in reinforced concrete members, by incorporating commercial barometric pressure MEMS sensors in appropriate sealed cavities embedded in the reinforcing steel bars. The results of an experimental campaign are reported, in which a reinforced concrete beam, instrumented with both S3 devices and conventional electrical strain gauges, is subjected to increasing loading and unloading cycles until collapse. The tests show the superior robustness of the S3 system during construction and loading as well as its good sensing accuracy, demonstrating its potential for a massive use in SHM applications

    Apolipoprotein E Allelic Frequency Altered in Women with Early-onset Breast Cancer

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    Among women, the most prevalent type of cancer is breast cancer, affecting 1 out of every 8 women in the United States; in Puerto Rico, 70 out of every 100,000 will develop some type of breast cancer. Therefore, a better understand of the potential risk factors for breast cancer could lead to the development of early detection tools. A gene that has been proposed as a risk factor in several populations around the world is Apolipoprotein E (apoE). ApoE functions as a mechanism of transport for lipoproteins and cholesterol throughout the body, with 3 main isoforms present in humans (apoE2, apoE3, and apoE4). Whether or not apoE4 is a risk factor for breast cancer remains controversial. Previous studies have either included test subjects of all ages (20–80) or have focused on late-onset (after age 50) breast cancer; none has concentrated specifically on early-onset (aged 50 and younger) breast cancer. The objectives of this study was to examine (in a Puerto Rican population) the differences in the relative frequency of occurrence of apoE4 in non-breast cancer versus breast cancer patients and to examine, as well, the potential differences of same in early- versus late-onset patients. We found an increased frequency of apoE4 (odds ratio 2.15) only in early-onset breast cancer survivors, which is similar to the findings of those studies that combined or adjusted for age as well as for an association between apoE4 and decreased tumor size. ApoE is also a potential risk factor for long-term cognitive effects after chemotherapy and affects response to hormone replacement. Our data supports the theory that knowing the apoE genotype of women who are at risk of developing breast cancer may be beneficial, as such knowledge would aid in the prediction of tumor size and the development of treatment regimens

    Potencialidades do guandu como adubação verde em áreas cultivadas com cana-de-açúcar nos tabuleiros costeiros de Alagoas.

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    Grande parte da produção de cana-de-açúcar em Alagoas está concentrada nos tabuleiros costeiros, região litorânea com precipitação favorável ao desenvolvimento da cultura. Contudo, os solos de tabuleiros apresentam algumas limitações agrícolas referentes à baixa resistência mecânica a operações de preparo de solo, baixa fertilidade natural e de retenção de água e nutrientes. Os solos são caracterizados ainda por apresentarem uma alta coesão natural dos horizontes, o que dificulta a penetração e desenvolvimento radicular das plantas, a disponibilidade de água, a aeração e a absorção de nutrientes, podendo influenciar negativamente no desenvolvimento das culturas.bitstream/item/123063/1/Potencialidades-do-guandu.pd
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