This paper presents simulated results of Partial Discharge Inception Voltage (PDIV) for a semi-complex geometry. Reduction of CO 2 in aeronautical domain can be reached with various approaches, ...increasing electrical power is one of them. In order to keep reasonable cable weight (conductors more specifically), increasing network voltages can be a key factor. This can lead however to apparition of partial discharges. AIRLIFT is a program, developed at IRT Antoine Saint Exupéry, based on Finite Element Methods simulation to predict a numerical inception voltage of partial discharge. This paper focuses on motorette geometry with comparison of simulated and experimental PDIV and capacitance.
Oncogénétique en oncopédiatrie Abadie, C.; Gauthier-Villars, M.; Sirvent, N. ...
Archives de pédiatrie : organe officiel de la Société française de pédiatrie,
August 2012, Letnik:
19, Številka:
8
Journal Article
Recenzirano
Les prédispositions héréditaires aux cancers de l’enfant sont présentes chez environ 10 % des enfants atteints de tumeurs malignes. Ces prédispositions concernent aussi bien des tumeurs très rares ...comme le blastome pleuro-pulmonaire, le corticosurrénalome, l’hépatoblastome, les tumeurs rhabdoïdes, le gliome des voies optiques ; rares comme le rétinoblastome, le médulloblastome, le néphroblastome ; ou plus fréquentes comme les sarcomes, le neuroblastome et les leucémies. Leur identification revêt un enjeu tant individuel que familial permettant ainsi une prise en charge optimisée médicale voire chirurgicale pour l’enfant et ses apparentés. Pour des futurs enfants à naître, il peut parfois être proposé un diagnostic prénatal ou pré-implantatoire. Cette mise au point présente les principaux syndromes de prédispositions héréditaires aux tumeurs malignes de l’enfant. À partir du type histologique de la tumeur, nous déclinerons les différentes orientations diagnostiques pour ces syndromes de prédisposition.
Tumor predisposition in children is rare, accounting for approximately 10% of all cancers in childhood. Tumor predisposition involves very rare tumors such as pleuropulmonary blastoma, adrenocortical carcinoma, hepatoblastoma, rhabdoid tumors, optic pathway glioma, as well as rare tumors such as retinoblastoma, medulloblastoma, nephroblastoma, or more frequent tumors such as sarcomas, neuroblastoma, and leukemias. The identification of these predispositions is important for improved management for both the child and relatives. Prenatal and preimplantation genetic diagnosis are options that could be considered for young parents in a perspective of future pregnancies. This manuscript describes the main tumor predispositions in childhood. From each histological subtype, the different diagnosis directions are discussed in view of these main tumor predispositions.
Carbonyl sulfide (COS) is an atmospheric trace gas of interest for
C cycle research because COS uptake by continental vegetation is strongly
related to terrestrial gross primary productivity (GPP), ...the largest and
most uncertain flux in atmospheric CO2 budgets. However, to use
atmospheric COS as an additional tracer of GPP, an accurate quantification
of COS exchange by soils is also needed. At present, the atmospheric COS
budget is unbalanced globally, with total COS flux estimates from oxic and
anoxic soils that vary between −409 and −89 GgS yr−1. This uncertainty
hampers the use of atmospheric COS concentrations to constrain GPP estimates
through atmospheric transport inversions. In this study we implemented a
mechanistic soil COS model in the ORCHIDEE (Organising Carbon and Hydrology In Dynamic Ecosystems) land surface model to simulate
COS fluxes in oxic and anoxic soils. Evaluation of the model against flux
measurements at seven sites yields a mean root mean square deviation of 1.6 pmol m−2 s−1, instead of 2 pmol m−2 s−1 when using a previous
empirical approach that links soil COS uptake to soil heterotrophic
respiration. However, soil COS model evaluation is still limited by the
scarcity of observation sites and long-term measurement periods, with all
sites located in a latitudinal band between 39 and
62∘ N and no observations during wintertime in this study. The new
model predicts that, globally and over the 2009–2016 period, oxic soils act
as a net uptake of −126 GgS yr−1 and anoxic soils are a source of
+96 GgS yr−1, leading to a global net soil sink of only −30 GgS yr−1, i.e. much smaller than previous estimates. The small magnitude
of the soil fluxes suggests that the error in the COS budget is dominated by
the much larger fluxes from plants, oceans, and industrial activities. The
predicted spatial distribution of soil COS fluxes, with large emissions from
oxic (up to 68.2 pmol COS m−2 s−1) and anoxic (up to 36.8 pmol COS m−2 s−1) soils in the tropics, especially in India and in the
Sahel region, marginally improves the latitudinal gradient of atmospheric
COS concentrations, after transport by the LMDZ (Laboratoire de Météorologie Dynamique) atmospheric transport model.
The impact of different soil COS flux representations on the latitudinal
gradient of the atmospheric COS concentrations is strongest in the Northern
Hemisphere. We also implemented spatiotemporal variations in near-ground
atmospheric COS concentrations in the modelling of biospheric COS fluxes,
which helped reduce the imbalance of the atmospheric COS budget by lowering
soil COS uptake by 10 % and plant COS uptake by 8 % globally (with a
revised mean vegetation budget of −576 GgS yr−1 over 2009–2016).
Sensitivity analyses highlighted the different parameters to which each soil
COS flux model is the most responsive, selected in a parameter optimization
framework. Having both vegetation and soil COS fluxes modelled within
ORCHIDEE opens the way for using observed ecosystem COS fluxes and larger-scale atmospheric COS mixing ratios to improve the simulated GPP, through
data assimilation techniques.
Development of waste tire modified concrete Li, Guoqiang; Stubblefield, Michael A.; Garrick, Gregory ...
Cement and concrete research,
12/2004, Letnik:
34, Številka:
12
Journal Article
Recenzirano
In this study, waste tire modified concrete was investigated experimentally. Two types of waste tire configurations were evaluated. One was in the form of chips, or particles, and the other was in ...the form of fibers. For the waste tire chip modified concrete, surface treatment by saturated NaOH solution and physical anchorage by drilling a hole at the center of the chips were also investigated. For the waste tire fiber modified concrete, fibers with various aspect ratios were utilized. A hybrid fiber reinforcement using waste tire fiber and polypropylene (PP) fiber was also investigated. The effect of waste tire resources (car tires or truck tires) on the strength and stiffness was evaluated. A total of 10 batches of concrete, which yielded sixty
φ152.4×304.8 mm cylinders, were prepared. Compressive strength, compressive modulus of elasticity, Poisson's ratio, and split tensile strength tests were conducted on the prepared samples. Ways to further recover the lost strength and stiffness of waste tire modified concrete were discussed based on the test results.
Peroxisome proliferators (PPs) are a class of rodent nongenotoxic hepatocarcinogens that cause hepatocyte peroxisome proliferation, increased DNA synthesis, and decreased spontaneous apoptosis. We ...examined the effects of various PPs such as the hypolipidemic agents clofibric acid (CLO), bezafibrate (BEZA), ciprofibrate (CIPRO), and nafenopin (NAFE) and the plasticizer di-(2-ethylhexyl)phthalate (DEHP) on the various parameters in vitro in rat and human hepatocyte cultures. In rat hepatocyte cultures, after 72 h of treatment with the various PPs at 100–500 μM, a compound-dependent increase in acyl CoA oxidase (ACO) and carnitine acetyl transferase (CAT) activities, markers of peroxisome proliferation, was observed with the following potencies: CIPRO = NAFE > BEZA > CLO > DEHP. A minor (120–150%), but significant, no concentration-dependent increase in DNA synthesis and a marked, no compound-dependent and, with the exception of NAFE, no concentration-dependent 60–80% decrease in spontaneous apoptosis was observed with all tested compounds (50–250 μM) after 48 h of treatment. Inhibition of spontaneous apoptosis in PP-treated versus control rat hepatocyte cultures was also observed morphologically. Furthermore, PPs inhibited transforming growth factor β (TGFβ)-induced apoptosis but not tumor necrosis factor α (TNFα)/α Amanitine (αAma)-induced apoptosis in rat hepatocyte cultures. In human hepatocyte cultures, the various PPs at 50–500 μM did not affect peroxisomal enzyme activities, DNA synthesis, or spontaneous and induced (TGFβ or TNFα/αAma) apoptosis. The compound-dependent peroxisome proliferation but no compound-dependent disruption of the mitogenic/apoptotic balance elicited by PPs in primary rat hepatocyte cultures supports the hypothesis that oxidative stress is directly linked to the hepatocarcinogenic potential of a given PP in rodents and that disruption of the mitogenic/apoptotic balance contributes to the development of PP-induced hepatocarcinogenesis. In addition, the absence of effects of all PPs on both peroxisome proliferation-associated parameters and mitogenic/apoptotic balance supports the hypothesis that human liver cells are refractory to PP-induced hepatocarcinogenesis.
•We built a foliar disease mechanistic model to simulate BLSD on a banana plant.•The model couples perennial host growth and complex pathogen epidemic cycle.•We present the Bayesian inference of the ...most influent pathogen parameters.•Model evaluation suggests realistic predictions of disease dynamics.•Simulations allow identifying disease control using plant resistance and plant growth.
Black leaf streak disease (BLSD), caused by the fungal pathogen Mycosphaerella fijiensis, is considered as the most destructive foliar disease of banana. To advance our knowledge of the dynamics of the disease at plant scale as well as of the components of varietal resistance, we designed, calibrated and evaluated a mechanistic model to simulate the disease on a banana plant. The model runs in discrete time at plant scale and describes plant growth and pathogen dynamics under optimal epidemiological conditions. The model is divided into two modules: a deterministic plant sub-model that simulates the simplified architecture and growth of the banana, and a pathogen sub-model that simulates the detailed life cycle of the pathogen including infection, lesion growth, asexual and sexual sporulation, and the dispersal of spores on the plant. The three most influential epidemiological parameters identified by sensitivity analysis of the model (lesion growth rate, infection efficiency, and incubation period) were estimated in a Bayesian framework using Markov chain Monte Carlo methods and acquired data on the dynamics of leaf lesions under natural conditions. The posterior densities provided precise knowledge on pathogen life history traits. The evaluation of the model using an independent data set confirmed the good quality of the predictions. Simulations allowed us to evaluate the impact of host resistance components, auto-infection at plant scale, and of the leaf emergence rate, which is linked with cropping practices, on the severity of BLSD. This foliar disease simulation model will help design new methods of controlling BLSD.
Research shows that by improving pavement surface friction resistance, wet pavement crashes can be reduced or prevented. However, the current asphalt mixture design procedure does not directly ...consider friction as a design requirement. The main objective of this study was to develop a procedure to predict the pavement field skid resistance based on design traffic input, aggregate polishing, and mixture properties commonly available during a mix design. Twenty-two asphalt pavement test sections were considered in this study. The selected asphalt mixtures consisted of eight commonly used aggregates and four typical mix types: 12.5-mm Superpave®, 19-mm Superpave, stone mastic asphalt, and open-graded friction course. Field measurements were conducted with the dynamic friction tester, circular texture meter, and locked-wheel skid tester devices, while the coarse aggregate’s polished stone values were determined by using the accelerated polishing test in the laboratory. Statistical analysis of various field and lab test results led to the development of a procedure for predicting pavement end-of-life skid resistance based on the aggregate blend’s polished stone values, gradation parameters, and design traffic input. In addition, a new aggregate friction rating table was developed so that new aggregate sources can be certified by laboratory dynamic friction tester measurements to fulfill the required mixture friction requirements. The new procedure will allow engineers to check whether a mix design with a selected blend of aggregates would meet field friction requirements during the mix design stage.
High aspect-ratio etchings are a key aspect of the fabrication of III–V semiconductor devices. The increasing demand for diverse geometries with various characteristic lengths (from the micro- to the ...nano-meter scale) requires the constant development of new etching recipes. In this article, we demonstrate a versatile mask-plasma combination for micro- and nanofabrication of GaAs substrate using an Inductive Coupled Plasma-Reactive Ion Etching (ICP-RIE) system. We identify five recipes at 25 °C, with high selectivity, and apply them on one photoresist (AZ4562) and two hard (chromium and nickel) masks. The optimized etching plasma chemistry (BCl3/Cl2/Ar/N2) shows a pattern transfer on GaAs with a high rate (≥5.5 μm/min), a high anisotropy, a high selectivity (>4:1 with photoresist mask, and >50:1 with hard masks), a good etch surface morphology, and smooth sidewalls profile (>88°). Herein, we detail the requirements definition, the engineering processes with detailed recipes, the verification, and validation of three device geometries (ridges, cylinders, and nanopillars). The presented results can be valuable for a wide range of applications from the microscale to the nanoscale, and are compatible with a manufacturing process using only a single commercial ICP-RIE tool with two chambers dedicated, respectively, for metallic masks and photoresist mask.
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