86 research outputs found
Effective synchronization of a class of Chua's chaotic systems using an exponential feedback coupling
In this work a robust exponential function based controller is designed to
synchronize effectively a given class of Chua's chaotic systems. The stability
of the drive-response systems framework is proved through the Lyapunov
stability theory. Computer simulations are given to illustrate and verify the
method.Comment: 12 pages, 18 figure
Finite-time synchronization of tunnel diode based chaotic oscillators
This paper addresses the problem of finite-time synchronization of tunnel
diode based chaotic oscillators. After a brief investigation of its chaotic
dynamics, we propose an active adaptive feedback coupling which accomplishes
the synchronization of tunnel diode based chaotic systems with and without the
presence of delay(s), basing ourselves on Lyapunov and on Krasovskii-Lyapunov
stability theories. This feedback coupling could be applied to many other
chaotic systems. A finite horizon can be arbitrarily established by ensuring
that chaos synchronization is achieved at a pre-established time. An advantage
of the proposed feedback coupling is that it is simple and easy to implement.
Both mathematical investigations and numerical simulatioComment: 11 pages, 43 figure
Développement d'une corrélation prédisant l'apparition du FCC dans un tube vertical chauffé uniformément en convection forcée avec un écoulement ascendant d'eau
Le flux de chaleur critique (FCC) est le plus important paramètre thermohydraulique qui
détermine le fonctionnement sécuritaire et efficace des systèmes énergétiques thermiques. Il est
défini comme celui qui provoque la détérioration soudaine du transfert de chaleur sur une surface
où il y a une ébullition, due à son assèchement lors de certaines conditions thermohydrauliques.
Ceci peut se traduire par une augmentation soudaine de la température de la surface, et par
conséquent causer sa destruction.
Ainsi, une analyse de sûreté adéquate d’un système énergétique thermique doit tenir compte de
l’apparition possible du FCC afin d’éviter des conséquences graves. Les industries de production
d’énergie nucléaire des efforts considérables pour arriver à comprendre ce phénomène.
À cause de la grande complexité du phénomène critique, les données expérimentales sont
principalement à la base du développement des connaissances sur le FCC. Ces données
permettent de créer des corrélations et des modèles servant à prédire l’apparition de ce
phénomène. Incidemment, elles servent à développer des technologies fiables et sécuritaires.
Toutefois, les données expérimentales sur le FCC sont rarement publiées et sont souvent la
propriété exclusive des organisations qui les détiennent.
Ce rapport consiste en une recherche bibliographique sur le FCC et en une Ă©valuation qualitative
et quantitative des données collectées par différents chercheurs afin de créer une base de données
fiable et présentant des résultats de FCC pour plusieurs conditions expérimentales. Une procédure
numérique de validation des données a été établie pour assurer leur validité en minimisant les
erreurs possibles. Suite à l’analyse des données recueillies, une corrélation permettant de prédire
le FCC a été développée.----------Abstract The critical heat flow (CHF) is the most important thermal-hydraulic parameter which determines
the safety and the efficiency of thermal energy systems. It is defined as the sudden decrease of the
heat transfer coefficient on a heated surface on which boiling or evaporation is taking place.
A good safety analysis of a thermal energy system must take into account the possible occurrence
of the CHF conditions in order to avoid their serious consequences. Nuclear and conventional
power industries have deployed enormous resources to better understand this phenomenon for
pool and flow boilings.
Experimental data form the basis for the advancement development of knowledge on CHF. They
make it possible to create correlations and models that help to predict the occurence of this
phenomenon. Incidentally, they are used to develop reliable and safe technologies. However, the
experimental data on the CHF are seldom published and are often the exclusive property of the
organizations which hold them.
This report consists of a literature survey on the CHF and a qualitative and quantitative evaluation
of the data collected by various researchers. A numerical procedure for validating the data was
established to assure their validity by minimizing the possible errors. Following the analysis of
the data collected, a correlation predicting the FCC has been developed
Influence of Carbohydrates on Callus Proliferation During Somatic Embryogenesis in Pineapple [Ananas Comosus (L.) Merr. (Bromeliaceae) Var. Cayenne Smooth Cultivar CI 16]
The improvement of pineapple (Ananas comosus var. Smooth Cayenne) by means of in vitro culture is less studied in Côte d'Ivoire despite the importance of this plant for this country’s economy. Our work consisted in highlighting nature and concentration effects of carbohydrates on the proliferation of calli in pineapple as a prelude to efficient embryogenesis. Callus proliferation was carried out from the base of pineapple vitroplants leaves. Thirty (30) explants were cultured on the tested culture medium. MS medium (micro- and macro elements of Murashige and Skoog) supplemented with vitamin Gamborg B5 was used as base medium to which were added 0.05 mg/L BAP, 3 mg/L picloram, 2 mg/L glycine, 1,000 mg/L glutamine, 100 mg/L casein hydrolyzate and 30 g/L carbohydrate. Sucrose was tested at different concentrations (20, 25, 30, 35 and 40 g/L). The results revealed that callus proliferation is strongly influenced (p ˂ 0.0001) by nature and concentration of carbohydrate. Sucrose with the highest dry matter content (61.34 mg) has a higher callogenic potential than the other studied carbohydrates. The concentration of 30 g/L sucrose significantly improved the calli proliferation in pineapple. Galactose and maltose were less favorable to proliferation
Effect of culture medium composition on somatic embryos induction and maturation of pineapple [Ananas comosus (L.) var. (Smooth Cayenne)]
The cultivation of pineapple contributes 1.6% of the gross Ivorian national product (GDP). However, this crop is facing a severe production crisis due to the aging of the orchards. Revising this sector requires the rejuvenation of orchards with healthy and improved planting material. This work was conducted to study the conditions for the efficient in vitro production of restorative pineapple planting material by somatic embryogenesis. The effects of seven culture media consisting of a different combination of nitrogen sources (casein hydrolyzate, glutamine, and glycine), cytokinins (kinetin or BAP), and auxins (2,4-D or picloram) were tested on somatic embryos induction and maturation in pineapple. Results of the study revealed that EIM1 (EIM added with 3 mg.L-1 picloram, 0.05 mg.L-1BAP, 2 mg.L-1 glycine, 1000 mg.L-1glutamine, 100 mg.L-1casein hydrolyzate) and EIM5 (EIM added with 2 mg.L-1glycine, 100 mg.L-1casein hydrolyzate, 0.2 mg.L-1kinetin) media induced the highest numbers of embryogenic cells, i.e., 154 and 149 cells respectively. Further, the EIM5 medium was more embryogenic, with the most significant number of mature embryos (66 mature embryos), and allowed the observation of all embryonic maturation stages. Embryogenic cell induction in pineapple is thought to be controlled by a low NH4+/NO3- ratio in interactions with phytohormones. In the presence of 2,4-D, embryogenic cell maturation was improved by kinetin addition to the culture medium containing glycine and casein hydrolyzate
Latex micro diagnosis, modern management tool of rubber plantations of clones with moderate metabolism GT 1, RRIC 100 and BPM 24
Objective: The cultivated rubber clones are sensitive to latex harvesting regimes according to their laticiferous metabolism. This study was done to determine the best latex harvesting system (s) of clones with moderate metabolism (GT 1, RRIC 100 and BPM 24).Methodology and Results: Six latex harvesting technologies were applied to these clones in a bulk statistical device from Fisher to four rehearsals. The rubber trees were tapped in downward half spiral stimulated or not, for nine years after the opening of the tapping panel. The agronomic parameters (latex production, vegetative growth), the tapping panel dryness and those of the latex micro diagnosis were evaluated. The results indicate that these clones independently of the latex harvesting system have good rubber productivity (2234 kg.ha-1.y-1) with good radial vegetative growth (2.4 cm.y-1). Their trees showed a well-balanced physiological profile and an acceptable sensitivity to the tapping panel dryness (3.2 %). However, the physiological index, the bark consumption and the sensitivity to the tapping panel dryness lead to retain the latex harvesting technology "S/2 d4 6d/7 Pa1 (1) ET2.5% 4/y” for the best.Conclusion and application of results: This index, favourably influencing the choice of technologies adapted to clones with active metabolism, contributes to the modern and efficient management of a rubber plantation.Key words: latex-harvesting technology, rubber clones, moderate metabolism, tapping panel dryness, physiological parameter
Latex Micro Diagnosis, Modern Management Tool of Rubber Plantations of Clones With Active or Rapid Metabolism IRCA 18, IRCA 130, PB 235, PB 260 and PB 330
The cultivated rubber clones are sensitive to latex harvesting regimes according to their laticiferous metabolism. Thus, in order to determine the best latex harvesting systems of clones with active or rapid metabolism (IRCA 18, IRCA 130, PB 235, PB 260 and PB 330), six latex harvesting technologies are applied to them in a bulk statistical device from Fisher to four rehearsals. The rubber is tapped in downward half spiral stimulated or not for nine years after the opening of the tapping panel. The agronomic parameters (production, vegetative growth), the tapping panel dryness and those of the latex micro diagnosis were evaluated. The results indicate that these clones independently of the latex harvesting system have good rubber productivity (2310 kg.ha -1.y1) with good radial vegetative growth (2.9 cm.y-1). Their trees show a wellbalanced physiological profile and an acceptable sensitivity to the tapping panel dryness (4.9%). However, the physiological index, the bark consumption and the sensitivity to the tapping panel dryness lead to retain the latex harvesting technologies “ S/2 d3 6d/7 Pa1(1) ET2.5% 4/y and S/2 d4 6d/7 Pa1(1) ET2.5% 4/y ” for the best. This index, favorably influencing the choice of technologies adapted to clones with active metabolism, contributes to the modern and efficient management of a rubber plantation
Contribution of Latex Micro Diagnosis to Modern Management of Rubber Plantations: Case of Clones With Low or Slow Metabolism PB 217 and PR 107
The cultivated rubber clones are sensitive to latex harvesting regimes according to their laticiferous metabolism. Thus, in order to determine the best latex harvesting systems of clones with low or slow metabolism, six latex harvesting technologies are applied to them in a bulk statistical device from Fisher to four rehearsals. The rubber is tapped in downward half spiral stimulated or not for nine years after the opening of the tapping panel. The agronomic parameters (production, vegetative growth), the tapping panel dryness and those of the latex micro diagnosis were evaluated. The results indicate that these clones independently of the latex harvesting system have good rubber productivity (2310 kg.ha -1 .y-1 ) with good radial vegetative growth (2.9 cm.y -1 ). Their trees show a well-balanced physiological profile and an acceptable sensitivity to the tapping panel dryness (4.9%). However, the physiological index, the bark consumption and the sensitivity to the tapping panel dryness lead to retain the latex harvesting technologies "S/2 d3 6d/7 Pa1(1) ET2.5% 4/y, S/2 d4 6d/7 Pa1(1) ET2.5% 4/y and S/2 d4 6d/7 Pa1(1) ET2.5% 8/y” for the best. This index, favorably influencing the choice of technologies adapted to clones with active metabolism, contributes to the modern and efficient management of a rubber plantation
Variation des Composés Phénoliques suite à l’Elicitation du Cotonnier suivie d’Inoculation à Fusarium Oxysporum F. Sp. Vasinfectum
La fusariose causée par Fusarium oxysporum f. sp. vasinfectum est une maladie qui entraîne le plus de dommages dans la culture cotonnière. Cependant, l’utilisation de pesticides notamment les fongicides comme solution pour faire face à l’agent pathogène s’est avérée non seulement inefficace mais entraîne des problèmes de toxicité, de pollution de l’environnement, de santé et même de biodiversité. L’objectif de ce travail a été d’étudier la variabilité de la production de composés phénoliques impliqués dans le système de défense naturelle du cotonnier. Ainsi, l’application des éliciteurs MeJA et FOS11 (10%) sur les plants de cotonnier suivis d’inoculation à FOV a permis la synthèse de novode composés phénoliques en plus des composés préexistants. Par ailleurs, l’accumulation des composés phénoliques a été amplifiée suite à l’application de ces deux éliciteurs suivie de l’inoculation à FOV. Les plants de cotonnier ont été donc équipés de composés qui ont anticipés l’attaque de FOV. Toutefois, la FOS11 (10%) a induit la production d’un plus grand nombre de composés phénoliques que le MeJA. La FOS11 (10%) a donc été retenu comme meilleur éliciteur naturelle de la stimulation des défenses naturelles du cotonnier. Fusarium blight caused by Fusarium oxysporum f. sp. vasinfectum is a disease that causes the most damage in cotton growing. However, the use of pesticides, especially fungicides as a solution to the pathogen, has proven to be not only ineffective but also leads to problems of toxicity, environmental pollution, health and even biodiversity. The objective of this work wasto study the variability of the production of phenolic compounds involved in the natural defense system of the cotton plant. Thus, the application of the MeJA and OSF 11 elicitors (10%) on the cotton plants followed by inoculation with FOV allowed the de novo synthesis of phenolic compounds in addition to the preexisting compounds. Moreover, the accumulation of phenolic compounds was amplified following the application of these two elicitors followed by inoculation with FOV. The cotton plants were therefore equipped with compounds that anticipated the FOV attack. However, OSF 11 (10%) induced the production of more phenolic compounds than MeJA. OSF 11 (10%) was therefore chosen as the best natural elicitor of the stimulation of the natural defenses of cotton
Architectures for Multinode Superconducting Quantum Computers
Many proposals to scale quantum technology rely on modular or distributed
designs where individual quantum processors, called nodes, are linked together
to form one large multinode quantum computer (MNQC). One scalable method to
construct an MNQC is using superconducting quantum systems with optical
interconnects. However, a limiting factor of these machines will be internode
gates, which may be two to three orders of magnitude noisier and slower than
local operations. Surmounting the limitations of internode gates will require a
range of techniques, including improvements in entanglement generation, the use
of entanglement distillation, and optimized software and compilers, and it
remains unclear how improvements to these components interact to affect overall
system performance, what performance from each is required, or even how to
quantify the performance of each. In this paper, we employ a `co-design'
inspired approach to quantify overall MNQC performance in terms of hardware
models of internode links, entanglement distillation, and local architecture.
In the case of superconducting MNQCs with microwave-to-optical links, we
uncover a tradeoff between entanglement generation and distillation that
threatens to degrade performance. We show how to navigate this tradeoff, lay
out how compilers should optimize between local and internode gates, and
discuss when noisy quantum links have an advantage over purely classical links.
Using these results, we introduce a roadmap for the realization of early MNQCs
which illustrates potential improvements to the hardware and software of MNQCs
and outlines criteria for evaluating the landscape, from progress in
entanglement generation and quantum memory to dedicated algorithms such as
distributed quantum phase estimation. While we focus on superconducting devices
with optical interconnects, our approach is general across MNQC
implementations.Comment: 23 pages, white pape
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