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16410
01/06/2017

A multi-phase micro-kinetic model for simulating aluminium based thermite reaction

V.BAIJOT, M.DJAFARI ROUHANI, C.ROSSI, A.ESTEVE

NEO

Revue Scientifique : Combustion and Flame, Vol.180, pp.10-19, Juin 2017 , N° 16410

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This paper presents a hierarchical multiscale approach based on a micro-kinetic model enabling to predict temperature, pressure and species generated during the thermite reaction of Al nanoparticles mixed with CuO nanoparticles. Overall, our phenomenological model integrates and combines series of complex atomistic mechanisms, e.g. diffusion and phase transformation, gas phase reactions and interphase exchange mechanisms, in particular molecular condensation, evaporation and decomposition. Thermodynamics considerations as well as Density Functional Theory (DFT) calculations are used to implement rate equations expressing the complex reactions at solid/liquid/gas interphases. We demonstrate that the model can predict the pressure–time dependence, the different phases and compositions with good accuracy at significantly low computational cost. The influence of Al and CuO particle size, compaction or density, alumina shell thickness and stoichiometry on the pressure and temperature versus time is theoretically predicted with fairly good agreement with available experimental data. A maximum pressure of 47 MPa and adiabatic temperature of 3500 K are obtained at high compaction, i.e. 50% of the TMD (Theoretical Maximum Density) for stoichiometric mixture, where AlO is shown to be the prevailing gaseous species. At low compaction, we highlight the role of ambient oxygen condition for which the model gives a maximal pressure of 4.2 MPa for Al rich mixtures (stoichiometric ratio of 1.2).

139192
16457
01/03/2017

Dioxygen molecule adsorption and oxygen atom diffusion on clean and defective Aluminum (111) surface using first principles calculations

A.HEMERYCK, M.GUILTAT, M.BRUT, S.VIZZINI

M3, IM2NP

Revue Scientifique : Surface Science, Vol.657, pp.79-89, Mars 2017 , N° 16457

Lien : https://hal.archives-ouvertes.fr/hal-01407658

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First principles calculations are conducted to investigate kinetic behavior of oxygen species at the surface of clean and defective Al(111) substrate. Oxygen island, aluminum vacancy, aluminum sub-vacancy, aluminum ad-atom and aluminum terraces defects are addressed. Adsorption of oxygen molecule is first performed on all these systems resulting in dissociated oxygen atoms in main cases. The obtained adsorbed configurations are then picked to study the behavior of atomic oxygen specie and get a detailed understanding on the effect of the local environment on the ability of the oxygen atom to diffuse on the surface. We pointed out that local environment impacts energetics of oxygen atom diffusion. Close packed oxygen island, sub-vacancy and ad-atoms favor oxygen atom stability and decrease mobility of oxygen atom on the surface, to be seen as surface area for further nucleation of oxygen island.

138449
16464
20/02/2017

Controlled permeation of lidocaine hydrochloride using a smart drug delivery system

Y.TALBI, D.BRULIN, E.CAMPO, J.Y.FOURNIOLS

S4M

Manifestation avec acte : IASTED International Conference on Biomedical Engineering ( BioMed ) 2017 du 20 février au 22 février 2017, Innsbruck (Autriche), Février 2017, 7p. , N° 16464

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Transdermal administration might be an interesting alternative to current routes of administration. It is noninvasive, avoids gastric side effects, and improves bioavailability of the molecules. However, due to the low permeability of the stratum corneum, a permeation enhancement strategy is required to make a large number of molecules suitable to this mode of administration. To overcome those limitations and deliver controlled drugs, a smart transdermal drug delivery system is designing. This paper focusses on the study of transdermal iontophoresis permeation of lidocaine hydrochloride (2%, w/w) across pig ear skin. In vitro iontophoresis experiments were conducted using Franz diffusion cells. Anodal iontophoresis was applied for 30 minutes at different current densities. Samples (1 mL) were withdrawn every 30 minutes from the receptor compartment and replaced with a fresh buffer and then analyzed using High Performance Liquid Chromatography (HPLC). Results highlight the relationship between current density, time of stimulation, and amount of lidocaine permeated.

139241
16480
10/02/2017

Fabrication and modeling of a capacitor microfluidically tuned by water

N.HABBACHI, H.BOUSSETTA, A.BOUKABACHE, M.A.KALLALA, P.PONS, K.BESBES

Monastir, MILE, MINC

Revue Scientifique : IEEE Electron Device Letters, Vol.38, N°2, pp.277-280, Février 2017, DOI: 10.1109/LED.2016.2644540 , N° 16480

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This letter presents fabrication and modeling of a continuously tunable microfluidic capacitor, which is composed of electrodes obtained by classical electrodeposition and microfluidic channels generated by lamination of SU-8 films. We show that the capacitance increases continuously between Cmin = 0.52 pF and Cmax = 18.5 pF following addition of deionized (DI) water in microchannels. The capacitance tuning range reaches 3460% at 500 MHz. The quality factor decreases from Qmax = 69 when the capacitor is empty to Qmin = 5.3 when it is fully filled with DI water. We also model the electric field and current distributions inside microfluidic channels, showing that electric field is cancelled as they are entirely filled with DI water.

138952
16463
27/01/2017

Tunable MEMS capacitor: influence of fluids

N.HABBACHI, H.BOUSSETTA, A.BOUKABACHE, M.A.KALLALA, P.PONS, K.BESBES

Monastir, MILE, MINC

Revue Scientifique : Electronics Letters, Vol.53, N°2, pp.72-73, Janvier 2017 , N° 16463

Lien : https://hal.laas.fr/hal-01415341

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In this letter we evaluate the effect of a dielectric liquid on the tunability of capacitor operating in RF domains. The RF measurement shows a high variations of the resonant frequency accompanied with a low insertion loss. Moreover, the fluid positions between electrodes modifies the capacitance value up to Tr = 6660% at 600MHz. The quality factor decreases in response of water filling from Qmax = 51.9 when it is empty to Qmin = 1.49 when it is fully filled. According to the FEM analysis, the change of the dielectric permittivity influences the capacitor performances. Essentially, the tuning range of the capacitance and the quality factor could reach respectively: Tr = 7660% and Qmin = 35.-

Abstract

In this letter we evaluate the effect of a dielectric liquid on the tunability of capacitor operating in RF domains. The RF measurement shows a high variations of the resonant frequency accompanied with a low insertion loss. Moreover, the fluid positions between electrodes modifies the capacitance value up to Tr = 6660% at 600MHz. The quality factor decreases in response of water filling from Qmax = 51.9 when it is empty to Qmin = 1.49 when it is fully filled. According to the FEM analysis, the change of the dielectric permittivity influences the capacitor performances. Essentially, the tuning range of the capacitance and the quality factor could reach respectively: Tr = 7660% and Qmin = 35.-

138674
17005
16/01/2017

Exploration des nanotechnologies ADN pour l'auto-assemblage de nanoparticules d'aluminium et d'oxyde de cuivre : application à la synthèse de matériaux énergétiques

T.CALAIS

NEO

Doctorat : INP de Toulouse, 16 Janvier 2017, 286p., Président: J.P.AIME, Rapporteurs: S.BIDAULT, D.GASPARUTTO, Examinateurs: Y.CHABAL, A.ESTEVE, R.M.SAUVAGE, Directeurs de thèse: C.ROSSI, A.BANCAUD , N° 17005

Lien : https://hal.laas.fr/tel-01482306

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Over the two last decades, DNA technologies have intensively been studied for the organization of matter at the nanoscale. Thanks to the bio recognition of two complementary DNA single-strands and their hybridization into the famous helicoidally structure, self-assembling of gold nanoparticles into highly ordered micrometer scale crystals has been demonstrated. The aim of this thesis is to explore this new nanotechnology for the self-assembly of Al and CuO nanoparticles driven by DNA hybridization into highly energetic nanocomposites by optimizing contact surfaces between reducer (Al) and oxidizer (CuO). We chose Streptavidin-biotin strategy to functionalize nanoparticles with DNA single strands. More precisely, the functionalization process includes four steps: (i) stabilization of Al and CuO nanoparticles into separate colloidal suspensions; (ii) Streptavidin grafting on Al and CuO nanoparticles; (iii) DNA grafting on Al and CuO Streptavidin-modified nanoparticles thanks to the addition of biotin function at the end of the DNA single strands; (iv) mixing of the two colloidal DNA-functionalized suspensions in order to realize the self-assembly. First, we precisely determined, characterized and optimized each step of the functionalization process. Then, we studied more precisely two key points of the process: we analyzed the interaction of DNA bases with technologically relevant oxide surfaces by studying the grafting of Thymidine by theoretical and experimental approaches; and we studied the influence of the coding sequence used for the DNA strands on the quality of the self-assembly, also by theoretical and experimental analyses. Finally, we optimized environmental conditions to realize the self-assembly of DNA-functionalized nanoparticles into energetic nanobiocomposites. Morphologies and energetic properties were established as a function of synthesis conditions, and the control of energetic performances of nanobiocomposites as a function of aggregation process was demonstrated.

Résumé

Les nanotechnologies ADN utilisées pour l’auto-assemblage de nanoparticules d’or ou de métaux nobles ont connu un important développement au cours des vingt dernières années, permettant l’organisation de particules agencées en nano-cristaux, grâce à la reconnaissance biologique inégalable de deux brins complémentaires d’ADN. L’objectif de ces travaux de thèse est d’adapter ces nanotechnologies à l’assemblage de nanoparticules d’Al et de CuO en vue d’élaborer des matériaux composites énergétiques à haute performance, grâce à l’augmentation des surfaces en contact entre réducteur (Al) et oxydant (CuO) par la maîtrise de l’organisation spatiale des nanoparticules. Ainsi, la fonctionnalisation séparée des nanoparticules d’Al et de CuO dispersées en solution colloïdale par des monobrins d’ADN complémentaires doit amener, après mélange des deux solutions colloïdales, à l’agrégation des particules par l’hybridation des brins d’ADN greffés en surface. La stratégie de fonctionnalisation choisie ici est générique : la protéine « Streptavidine » est d’abord greffée sur la nanoparticule, puis le brin d’ADN fonctionnalisé par un groupe biotine à une de ses extrémités, se fixe sur la Streptavidine. Au-delà de l’organisation de la matière à l’échelle nanométrique, l’enjeu double de ces travaux tient dans l’établissement d’un protocole de fonctionnalisation fiable et reproductible, propre aux procédés de micro-électronique, pour envisager un report de ces matériaux sur puce, mais également dans le contrôle des performances énergétiques grâce à l’ADN. Nous avons tout d’abord étudié l’interaction entre les bases de l’ADN et la surface des particules afin d’identifier les interactions non-spécifiques pouvant provoquer une agrégation non-maîtrisée. Dans un second temps, nous nous sommes appliqués à élaborer le protocole en caractérisant précisément chaque étape de fonctionnalisation. Nous avons ensuite étudié l’agrégation des particules fonctionnalisées en fonction de nombreux paramètres expérimentaux telles que la longueur de la chaîne ADN, la séquence de l’oligonucléotide, ou encore la composition saline de la solution. A cause de l’existence d’interactions non-spécifiques, nous avons optimisés ces paramètres de façon à assurer une agrégation dirigée uniquement par l’hybridation des brins d’ADN et améliorer ainsi de façon conséquente l’organisation spatiale des particules et les performances énergétiques des matériaux synthétisés. Enfin, nous avons démontré la possibilité de contrôler les performances énergétiques des nanobiocomposites en maîtrisant leur microstructure grâce à l’ADN.

Mots-Clés / Keywords
Nanothermites; Colloïdes; Auto-assemblage par ADN; Nanoparticules d'Al; Nanoparticules de CuO; Colloids; DNA Self-Assembly; Al nanoparticles; CuO Nanoparticles;

138695
17021
13/01/2017

Conception et développement d'un micro détonateur électrique intégrant des nanothermites pour l’amorçage par impact d’explosifs secondaires

L.GLAVIER

NEO

Doctorat : Université de Toulouse III - Paul Sabatier, Janvier 2017, 214p., Président: N.NOLHIER, Rapporteurs: G.BAUDIN, B.A.KHASAINOV, Examinateurs: F.JOUOT, L.RENAUD, Directeurs de thèse: C.ROSSI , N° 17021

Lien : https://hal.laas.fr/tel-01483791

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Pyrotechnic systems are the keys for satellite launching on orbit. Those systems are used for engines ignition, stage separation and self-destruction. To activate those functions, different kinds of initiators are used to generate a flame, pressure from gas expansion and a shock wave. This work involved following a previous thesis on the design of a smart and safe initiator able to generate a flame and pressure form gas expansion but not a shock wave which is essential in achieving certain functions on launcher as stage separation or neutralization. The initiator is controlled by digital controls, it contain local energy source, a mechanical safety barrier and a PyroMEMS for electro-pyrotechnical conversion. This initiator is design to replace Ariane 5 current pyrotechnic systems because they are heavy, bulky, they contain a large amount of pyrotechnic substance increasing the cost of manufacturing and storage. Also detonators and transmission lines contain lead banned by the European REACh. The goal of these thesis works is to design the detonator function from the flame generated by the PyroMEMS containing 50 µg of Al / CuO nanothermite in a volume less than 0,83 cm3 without primary explosive. After the study of secondary explosive priming methods and the state of art of existing detonators, we designed an architecture running on propelling a projectile creating a shock wave through impact. The development of this detonation function was used to study the behavior of different nanothermites (Al / CuO, Al / Bi2O3, Al / MoO3 and Al / PTFE) with a view to propel the projectile. An interior ballistic model is developed with the combustion nanothermite Al / Bi2O3 doped with PTFE to conclude that it is not possible to use nanothermites to ignite in detonation by impact, by a shock to Detonation Transition) a secondary explosive such as RDX. A propulsion system based on the combustion of RDX initiated by nanothermite is then developed with a study of the influence of dimensional parameters. Achieving a final demonstrator allows to ignite in detonation RDX demonstrates the feasibility of such a device and to validate design choices.

Résumé

Les systèmes pyrotechniques sont des éléments clés pour la réussite de la mise en orbite des satellites. Ils permettent de réaliser des fonctions vitales pour la phase de vol d'un lanceur spatial comme l'allumage des moteurs, la séparation d'étages ou la neutralisation. L'actionnement de ces systèmes pyrotechniques nécessite différents effets pyrotechniques comme la génération d'une flamme, d'une grande quantité de gaz et une onde de choc. Ces travaux de thèse interviennent à la suite d'une précédente thèse sur la conception d'un initiateur intelligent et sécurisés permettant de générer une flamme et une grande quantité de gaz mais pas une onde de choc, indispensable dans la réalisation de certaines fonctions pyrotechniques comme la séparation d’étages ou la neutralisation. L’initiateur est piloté par commandes numériques, il dispose d’un stockage local d’énergie, d’une barrière de sécurité mécanique, et d’un PyroMEMS permettant de convertir un signal électrique en un signal pyrotechnique. Cet initiateur est conçu pour remplacer les systèmes pyrotechniques actuellement utilisés sur Ariane 5 car ils sont lourds, encombrants, ils contiennent une grande quantité de substance pyrotechnique augmentant les coûts de fabrication et de stockage, pour finir, les détonateurs et les lignes de transmissions contiennent du plomb dont l’obsolescence est programmé par la règlementation Européenne REACh. L’objectif de ces travaux de thèse est de concevoir et de développer la fonction détonation à partir d’un PyroMEMS contenant moins de 50 µg de nanothermite Al / CuO dans un volume inférieur à 0,83 cm3. Après l’étude des méthodes d’amorçage d’explosif secondaire et de l’état de l’art des détonateurs existant, nous avons conçu une architecture fonctionnant sur la propulsion d’un projectile créant une onde de choc par impact. Le développement de cette fonction détonation a permis d’étudier le comportement de différentes nanothermites (Al / CuO, Al / Bi2O3, Al / MoO3 et Al / PTFE) dans l’optique de propulser le projectile. Un modèle de balistique intérieure est développé avec la combustion de nanothermite Al / Bi2O3 dopé avec du PTFE permettant de conclure qu’il n’est pas possible d’utiliser des nanothermites pour amorcer par impact un explosif secondaire tel que le RDX. Un système de propulsion basé sur la combustion du RDX initié par nanothermite est alors développé avec une étude de l’influence des paramètres dimensionnels. La réalisation d’un démonstrateur final qui permet d’amorcer en détonation du RDX démontre la faisabilité d’un tel dispositif et permet de valider des choix de conception.

Mots-Clés / Keywords
Balistique intérieure; Détonateur; Explosif secondaire; Nanothermites; PyroMEMS;

139022
16058
01/01/2017

Role of impurities, defects and their complexes on the trapping of hydrogen in bulk aluminium and on the Al(111) surface

J.M.DUCERE, M.DJAFARI ROUHANI, C.ROSSI, A.ESTEVE

NEO

Revue Scientifique : Computational Materials Science, Vol.126, pp.272-279, Janvier 2017 , N° 16058

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First principles calculations are performed to explore and quantify the stability of hydrogen in several Al environments including bulk Al and Al(1 1 1) surface, with the possible presence of vacancies and Mg, Cu and Zn impurities as substitutional defects in bulk or in the surface or as adatoms on the surface. In contrast to common statement, we show that hydrogen has a natural propensity to self-organize in bulk Al and demonstrate that vacancies can serve as nucleation centers for this process leading to massive hydrogen accumulation into aluminum. We then discuss the surface adatom defect and observe that it activates molecular hydrogen dissociation enabling further hydride insertion into bulk Al. Finally, we find that Mg, Cu, or Zn isolated impurities do not significantly impact hydrogen trapping indicating that structural defects rather than the local chemistry of isolated impurities are governing hydrogen accumulation in aluminum.

137733
16389
01/01/2017

Simulation of single particle displacement damage in silicon – Part II: Generation and long-time relaxation of damage structure

A.JAY, M.RAINE, N.RICHARD, N.MOUSSEAU, V.GOIFFON, A.HEMERYCK, P.MAGNAN

ISAE, CEA-DAM, UdeM, M3

Revue Scientifique : IEEE Transactions on Nuclear Science, Vol.64, N°1, pp.141-148, Janvier 2017 , N° 16389

Lien : https://hal.archives-ouvertes.fr/hal-01407740

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A statistical study of displacement cascades induced by silicon Primary Knock-on Atoms (PKA) in bulk silicon is performed by running a large number of molecular dynamics (MD) simulations. The choice of the PKA species and energy varying from 1 to 100 keV comes from a previous particle-matter simulation [1]. The electronic stopping power missing in standard MD simulations is here taken into account using the Two Temperature Model (TTM). This prevents from overestimating the number of created defects. The damaged atomic structures obtained after one nanosecond of MD simulation are not representative of what is observed in image sensors for example after several minutes. For this reason, the kinetic Activation Relaxation Technique (k-ART) is used in a second step, allowing to access longer simulation times of up to second. The obtained damaged structures can then be compared with experimental observations. Analyses reveal two possible links between the simulated structures and the measurements in solid-state image sensors. First, the cluster size distribution exhibits a shape similar to the measured exponential distribution of Dark Current (DC). Second, the temporal evolution of metastable atomic configurations resembles experimental DC-Random-Telegraph-Signals.

138193
16317
01/01/2017

Investigation of Al/CuO multilayered thermite ignition

A.NICOLLET, G.LAHINER, A.BELISARIO, S.ASSIE-SOULEILLE, M.DJAFARI ROUHANI, A.ESTEVE, C.ROSSI

NEO, I2C

Revue Scientifique : Journal of Applied Physics, Vol.121, N°3, 034503p., Janvier 2017 , N° 16317

Lien : https://hal.laas.fr/hal-01480996

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The ignition of the Al/CuO multilayered material is studied experimentally to explore the effects of the heating surface area, layering, and film thickness on the ignition characteristics and reaction performances. After the description of the micro-initiator devices and ignition conditions, we show that the heating surface area must be properly calibrated to optimize the nanothermite ignition performances. We demonstrated experimentally that a heating surface area of 0.25 mm2 is sufficient to ignite a multilayered thermite film of 1.6 mm wide by a few cm long, with a success rate of 100%. A new analytical and phenomenological ignition model based on atomic diffusion across layers and thermal exchange is also proposed. This model considers that CuO first decomposes into Cu2O, and then the oxygen diffuses across the Cu2O and Al2O3 layers before reaching the Al layer, where it reacts to form Al2O3. The theoretical results in terms of ignition response times confirm the experimental observation. The increase of the heating surface area leads to an increase of the ignition response time and ignition power threshold (go/no go condition). We also provide evidence that, for any heating surface area, the ignition time rapidly decreases when the electrical power density increases until an asymptotic value. This time point is referred to as the minimum response ignition time, which is a characteristic of the multilayered thermite itself. At the stoichiometric ratio (Al thickness is half of the CuO thickness), the minimum ignition response time can be easily tuned from 59 μs to 418 ms by tuning the heating surface area. The minimum ignition response time increases when the bilayer thickness increases. This work not only provides a set of micro-initiator design rules to obtain the best ignition conditions and reaction performances but also details a reliable and robust MicroElectroMechanical Systems process to fabricate igniters and brings new understanding of phenomena governing the ignition process of Al/CuO multilayers.

138972
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