Réduction de modèle en dynamique des structures et des systèmes couplés aéroélastiques

The numerical simulation of the dynamic behaviour of complex structures or aeroelastic coupled systems leads to systems of equations with very large size whose solution is very costly. It is thus essential to build reduced order models which allow to perform the simulations of these systems at a lesser cost and with an acceptable lost of accuracy. This model reduction is obtained by a projection of the initial system of equations on a projection basis, including therefore substructuring or component mode synthesis methods, as well as the cyclic symmetry reduction. We present here a set of methods using reduction or projection techniques. In the first part, we put together some works related to the eigen frequencies and modes: the block Lanczos method to compute the frequencies and modes of damped structures, a substructuring method to determine their sensitivity and their reanalysis, and finally a criterion to follow-up their evolution for structures depending on a parameter. The second part is devoted to component mode synthesis methods which include the classical methods, with fixed, free or hybrid interface, the methods using interface modes or partial interface modes, as well as their combination with cyclic symmetry reduction. The third part is concerned with multi-stage structures such as bladed-disk assemblies whose each stage has a cyclic symmetry but not the whole structure. A multi-stage cyclic symmetry reduction method has been developed with a new selection of phase indexes for each stage in each reduced system. It can be used alone or combined with component mode synthesis. The fourth part is concerned with the fluid-structure coupling in turbomachinery. The structure, a bladed disk having a cyclic symmetry, is subject to the aerodynamic forces applied by the fluid and which depend on the displacements of the structure. The projection of the equation of the structure on their complex eigen modes provides a reduced coupled system in which the generalized aerodynamic forces are obtained from the harmonic motions of the modes. Two solution methods and a multi-parameter modeling method are proposed to obtain the solutions of the coupled system for a large number of values of the parameters.La simulation numérique du comportement dynamique des structures ou des systèmes couplés aéroélastiques complexes conduit à des systèmes d'équations de très grande taille dont la résolution est très coûteuse. Il est donc indispensable de construire des modèles d'ordre réduit qui, au prix d'une diminution acceptable de la précision, permettent d'obtenir à moindre coût des simulations de ces systèmes. Cette réduction de modèle est obtenue par une projection du système d'équations initial sur une base de projection, incluant ainsi les méthodes de sous-structuration ou de synthèse modale, ainsi que la réduction par symétrie cyclique. On présente ici un ensemble de méthodes ayant recours aux techniques de réduction ou de projection. La première partie regroupe quelques travaux sur les fréquences et modes propres: la méthode de Lanczos par bloc pour calculer les fréquences et les modes propres de structures amorties, une méthode de sous-structuration pour déterminer leur sensibilité et leur réanalyse, et finalement un critère pour suivre leur évolution dans le cas des structures dépendant d'un paramètre. La deuxième partie est consacrée aux méthodes de synthèse modale, incluant les méthodes classiques, avec interface fixe, libre ou mixte, les méthodes utilisant les modes d'interface ou les modes d'interface partiels, ainsi que leur combinaison avec la réduction par symétrie cyclique. La troisième partie concerne les structures multi-étages comme les assemblages de disques aubagés dont chaque étage possède une symétrie cyclique mais pas la structure complète. Une méthode de réduction par symétrie cyclique multi-étages est développée avec une nouvelle sélection des indices de déphasage pour chaque étage dans chaque système réduit. Elle peut être utilisée seule ou combinée avec la synthèse modale. La quatrième partie concerne le couplage fluide-structure dans les turbomachines. La structure, un disque aubagé possédant une symétrie cyclique, est soumise à des forces aérodynamiques exercées par le fluide et qui dépendent des déplacements de la structure. La projection de l'équation de la structure sur ses modes propres complexes fournit un système réduit couplé dans lequel les forces aérodynamiques généralisées sont obtenues à partir des mouvements harmoniques des modes. Deux méthodes de résolution et une méthode de lissage multi-paramètres sont proposées afin d'obtenir les solutions du système couplé pour un grand nombre de valeurs des paramètre

Impacts of saltwater intrusion on soil nematodes community in alluvial and acid sulfate soils in paddy rice fields in the Vietnamese Mekong Delta

© 2020 Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license. https://creativecommons.org/licenses/by-nc-nd/4.0/Saltwater intrusion is a potential risk damaging crop diversity and productivity due to degraded soil physicochemical properties. However, little is known about how salinity affects the structure and function of soil nematodes community in intensive rice cultivated area. This study aimed (1) to assess the impacts of saltwater intrusion on the nematode community in alluvial and acid sulfate soils; and (2) to evaluate its relation with soil conditions. Saltwater intrusion reduced the abundance of both free-living nematodes (FLN) and plant-parasitic nematodes (dominated by Hirschmanniella) in soils. FLN community was different among sites with different physicochemical properties. The omnivorous genera Aporcelaimellus and Thornenema were only found in non-salt-affected alluvial soil, whilst Mesodorylaimus was dominant in salt-affected acid sulfate soil, suggesting that this genus might be tolerant to higher EC and soluble Na+, K+, Ca2+. The bacterivorous nematodes (dominant taxa Chronogaster, Rhabdolaimus) were dominant in both non-salt affected and salt-affected alluvial soils, which accounted for 48% and 40%, respectively, whilst it accounted for 21% in salt-affected acid sulfate soil. The abundance of fungivorous nematodes (Aphelenchoides, Ditylenchus, Filenchus) were greater in salt-affected alluvial soil in contrast to the other treatments, suggesting that these might be tolerant to salinity and low pH. Saltwater intrusion reduced biological diversity (Margalef, Shannon-Wiener, and Hill’s indices), maturity index (∑MI, MI25), and clearly affected functional guilds of nematode community, especially c-p 5 group was reduced in both salt-affected soils. This study suggests that saltwater intrusion showed a potential risk in the degradation of soil properties, as indicated by the altered nematode community, trophic structure, functional guilds and their ecological indices in paddy fields.Peer reviewedFinal Published versio

Two-level system with a thermally fluctuating transfer matrix element: Application to the problem of DNA charge transfer

Charge transfer along the base-pair stack in DNA is modeled in terms of thermally-assisted tunneling between adjacent base pairs. Central to our approach is the notion that tunneling between fluctuating pairs is rate-limited by the requirement of their optimal alignment. We focus on this aspect of the process by modeling two adjacent base pairs in terms of a classical damped oscillator subject to thermal fluctuations as described by a Fokker-Planck equation. We find that the process is characterized by two time scales, a result that is in accord with experimental findings.Comment: original file is revtex4, 10 pages, three eps figure

Comprehensive Pulmonary Safety Review of Inhaled Technosphere® Insulin in Patients with Diabetes Mellitus

Background and Objective: Technosphere® Insulin (TI), a human insulin powder for inhalation (Afrezza®; MannKind Corporation, Westlake Village, CA, USA), is an ultra-rapid-acting inhaled insulin indicated to improve postprandial glycemic control in patients with type 1 or type 2 diabetes mellitus (T1DM or T2DM). Because TI is absorbed across the alveolar membrane, the objective of this analysis was to characterize its pulmonary safety. Methods: Pooled data from 13 phase 2/3 clinical studies in 5505 patients with T1DM or T2DM treated with TI, Technosphere inhalation powder without insulin (TP; placebo), or active-comparator treatment were analyzed for incidences of respiratory treatment-emergent adverse events (TEAEs), changes in pulmonary function, and lung malignancies. Radiographic changes in the lungs were monitored in a subset of 229 patients. Results: Among 3017 patients receiving TI, the median duration of TI exposure was 168 days; median active-comparator and TP exposure durations were 363 and 149 days for 2198 and 290 patients, respectively. Respiratory TEAEs were comparable across treatments, except for a higher incidence of mild cough with TI in active-comparator studies (28.0% vs. 5.2%). Slight reversible declines in pulmonary function from baseline were observed for TI versus TP and active-comparator treatments, including in a subpopulation of patients with retrospectively identified lung dysfunction. Lung malignancies were reported in two patients on active TI therapy with a smoking history. No clinically significant changes from baseline were observed in radiographic images. Conclusions: Pulmonary safety assessment of the TI inhalation system did not identify any safety issues in individuals with either T1DM or T2DM

Photoproduction of mesons in nuclei at GeV energies

In a transport model that combines initial state interactions of the photon with final state interactions of the produced particles we present a calculation of inclusive photoproduction of mesons in nuclei in the energy range from 1 to 7 GeV. We give predictions for the photoproduction cross sections of pions, etas, kaons, antikaons, and $\pi^+\pi^-$ invariant mass spectra in ^{12}C and ^{208}Pb. The effects of nuclear shadowing and final state interaction of the produced particles are discussed in detail.Comment: Text added in summary in general reliability of the method, references updated. Phys. Rev. C (2000) in pres

Maintenance Therapy With Tumor-Treating Fields Plus Temozolomide vs Temozolomide Alone for Glioblastoma: A Randomized Clinical Trial.

IMPORTANCE: Glioblastoma is the most devastating primary malignancy of the central nervous system in adults. Most patients die within 1 to 2 years of diagnosis. Tumor-treating fields (TTFields) are a locoregionally delivered antimitotic treatment that interferes with cell division and organelle assembly. OBJECTIVE: To evaluate the efficacy and safety of TTFields used in combination with temozolomide maintenance treatment after chemoradiation therapy for patients with glioblastoma. DESIGN, SETTING, AND PARTICIPANTS: After completion of chemoradiotherapy, patients with glioblastoma were randomized (2:1) to receive maintenance treatment with either TTFields plus temozolomide (n = 466) or temozolomide alone (n = 229) (median time from diagnosis to randomization, 3.8 months in both groups). The study enrolled 695 of the planned 700 patients between July 2009 and November 2014 at 83 centers in the United States, Canada, Europe, Israel, and South Korea. The trial was terminated based on the results of this planned interim analysis. INTERVENTIONS: Treatment with TTFields was delivered continuously (>18 hours/day) via 4 transducer arrays placed on the shaved scalp and connected to a portable medical device. Temozolomide (150-200 mg/m2/d) was given for 5 days of each 28-day cycle. MAIN OUTCOMES AND MEASURES: The primary end point was progression-free survival in the intent-to-treat population (significance threshold of .01) with overall survival in the per-protocol population (n = 280) as a powered secondary end point (significance threshold of .006). This prespecified interim analysis was to be conducted on the first 315 patients after at least 18 months of follow-up. RESULTS: The interim analysis included 210 patients randomized to TTFields plus temozolomide and 105 randomized to temozolomide alone, and was conducted at a median follow-up of 38 months (range, 18-60 months). Median progression-free survival in the intent-to-treat population was 7.1 months (95% CI, 5.9-8.2 months) in the TTFields plus temozolomide group and 4.0 months (95% CI, 3.3-5.2 months) in the temozolomide alone group (hazard ratio [HR], 0.62 [98.7% CI, 0.43-0.89]; P = .001). Median overall survival in the per-protocol population was 20.5 months (95% CI, 16.7-25.0 months) in the TTFields plus temozolomide group (n = 196) and 15.6 months (95% CI, 13.3-19.1 months) in the temozolomide alone group (n = 84) (HR, 0.64 [99.4% CI, 0.42-0.98]; P = .004). CONCLUSIONS AND RELEVANCE: In this interim analysis of 315 patients with glioblastoma who had completed standard chemoradiation therapy, adding TTFields to maintenance temozolomide chemotherapy significantly prolonged progression-free and overall survival. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00916409

Structure and morphology of hydroxylated nickel oxide (111) surfaces

We report an experimental and theoretical analysis of the sqrt(3)x sqrt(3)-R30 and 2x2 reconstructions on the NiO (111) surface combining transmission electron microscopy, x-ray photoelectron spectroscopy, and reasonably accurate density functional calculations using the meta-GGA hybrid functional TPSSh. While the main focus here is on the surface structure, we also observe an unusual step morphology with terraces containing only even numbers of unit cells during annealing of the surfaces. The experimental data clearly shows that the surfaces contain significant coverage of hydroxyl terminations, and the surface structures are essentially the same as those reported on the MgO (111) surface implying an identical kinetically-limited water-driven structural transition pathway. The octapole structure can therefore be all but ruled out for single crystals of NiO annealed in or transported through humid air. . The theoretical analysis indicates, as expected, that simple density functional theory methods for such strongly-correlated oxide surfaces are marginal, while better consideration of the metal d-electrons has a large effect although, it is still not perfect.Comment: Replaces previous submission with smaller PDF file size. 32 pages including 9 figures and 2 table

Vector meson production and nucleon resonance analysis in a coupled-channel approach for energies m_N < sqrt(s) < 2 GeV II: photon-induced results

We present a nucleon resonance analysis by simultaneously considering all pion- and photon-induced experimental data on the final states gamma N, pi N, 2 pi N, eta N, K Lambda, K Sigma, and omega N for energies from the nucleon mass up to sqrt(s) = 2 GeV. In this analysis we find strong evidence for the resonances P_{31}(1750), P_{13}(1900), P_{33}(1920), and D_{13}(1950). The omega N production mechanism is dominated by large P_{11}(1710) and P_{13}(1900) contributions. In this second part we present the results on the photoproduction reactions and the electromagnetic properties of the resonances. The inclusion of all important final states up to sqrt(s) = 2 GeV allows for estimates on the importance of the individual states for the GDH sum rule.Comment: 41 pages, 26 figures, discussion extended, typos corrected, references updated, to appear in Phys. Rev.

Effect of Tumor-Treating Fields Plus Maintenance Temozolomide vs Maintenance Temozolomide Alone on Survival in Patients With Glioblastoma: A Randomized Clinical Trial.

Tumor-treating fields (TTFields) is an antimitotic treatment modality that interferes with glioblastoma cell division and organelle assembly by delivering low-intensity alternating electric fields to the tumor. To investigate whether TTFields improves progression-free and overall survival of patients with glioblastoma, a fatal disease that commonly recurs at the initial tumor site or in the central nervous system. In this randomized, open-label trial, 695 patients with glioblastoma whose tumor was resected or biopsied and had completed concomitant radiochemotherapy (median time from diagnosis to randomization, 3.8 months) were enrolled at 83 centers (July 2009-2014) and followed up through December 2016. A preliminary report from this trial was published in 2015; this report describes the final analysis. Patients were randomized 2:1 to TTFields plus maintenance temozolomide chemotherapy (n = 466) or temozolomide alone (n = 229). The TTFields, consisting of low-intensity, 200 kHz frequency, alternating electric fields, was delivered (≥ 18 hours/d) via 4 transducer arrays on the shaved scalp and connected to a portable device. Temozolomide was administered to both groups (150-200 mg/m2) for 5 days per 28-day cycle (6-12 cycles). Progression-free survival (tested at α = .046). The secondary end point was overall survival (tested hierarchically at α = .048). Analyses were performed for the intent-to-treat population. Adverse events were compared by group. Of the 695 randomized patients (median age, 56 years; IQR, 48-63; 473 men [68%]), 637 (92%) completed the trial. Median progression-free survival from randomization was 6.7 months in the TTFields-temozolomide group and 4.0 months in the temozolomide-alone group (HR, 0.63; 95% CI, 0.52-0.76; P &lt; .001). Median overall survival was 20.9 months in the TTFields-temozolomide group vs 16.0 months in the temozolomide-alone group (HR, 0.63; 95% CI, 0.53-0.76; P &lt; .001). Systemic adverse event frequency was 48% in the TTFields-temozolomide group and 44% in the temozolomide-alone group. Mild to moderate skin toxicity underneath the transducer arrays occurred in 52% of patients who received TTFields-temozolomide vs no patients who received temozolomide alone. In the final analysis of this randomized clinical trial of patients with glioblastoma who had received standard radiochemotherapy, the addition of TTFields to maintenance temozolomide chemotherapy vs maintenance temozolomide alone, resulted in statistically significant improvement in progression-free survival and overall survival. These results are consistent with the previous interim analysis. clinicaltrials.gov Identifier: NCT00916409

Measurements of long-range near-side angular correlations in sNN=5\sqrt{s_{\text{NN}}}=5TeV proton-lead collisions in the forward region

Two-particle angular correlations are studied in proton-lead collisions at a nucleon-nucleon centre-of-mass energy of $\sqrt{s_{\text{NN}}}=5$TeV, collected with the LHCb detector at the LHC. The analysis is based on data recorded in two beam configurations, in which either the direction of the proton or that of the lead ion is analysed. The correlations are measured in the laboratory system as a function of relative pseudorapidity, $\Delta\eta$, and relative azimuthal angle, $\Delta\phi$, for events in different classes of event activity and for different bins of particle transverse momentum. In high-activity events a long-range correlation on the near side, $\Delta\phi \approx 0$, is observed in the pseudorapidity range $2.0<\eta<4.9$. This measurement of long-range correlations on the near side in proton-lead collisions extends previous observations into the forward region up to $\eta=4.9$. The correlation increases with growing event activity and is found to be more pronounced in the direction of the lead beam. However, the correlation in the direction of the lead and proton beams are found to be compatible when comparing events with similar absolute activity in the direction analysed.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/lhcbproject/Publications/LHCbProjectPublic/LHCb-PAPER-2015-040.htm