Robust synchronization of a class of uncertain complex networks via discontinuous control

AbstractWe propose robust controller designs to synchronize networks with uncertainties in their node dynamics and their connections. We consider two situations: in the first, we assume that the effect of uncertainties vanishes as synchronization is achieved. In the second, disturbances are assume nonvanishing but bounded. To achieve robust synchronization on these situations, we design local feedback controllers, which are smooth in the first case, and discontinuous in the latter. These designs allow us to establish synchronization criteria for this class of uncertain dynamical networks. We use numerical experiments to illustrate our results

Oxidation of the borohydride Ion at silver nanoparticles on a glassy carbon electrode (GCE) using pulsed potential techniques

Direct oxidation borohydride fuel cells are very attractive energy conversion devices. Silver has been reported as one of the few materials which can catalyze an 8-electron oxidation. Potential step amperometric pulse techniques to synthesize nanostructured silver material on flat glassy carbon electrodes is reported and significant differences with bulk silver deposit have been observed. The oxidation of borohydride ion on the silver particles occurs at -0.025 V vs. SCE and the potential decreases towards negative values at longer cycle times. The oxidation current also decreases with the number of cycles, suggesting that the silver active sites become partially blocked by oxidation products of borohydride. The electroactive area per unit electrode area of silver was relatively low for particles deposited using potential step amperometric techniques on glassy carbon (0.002 cm2 per cm-2) compared with the area found at a polycrystalline silver electrode (0.103 cm2 per cm-2

Genealogical data of Boer and Nubian goats in Mexico

The pedigree file of the Boer and Nubian goat breeds in Mexico was constructed using the national database provided by the Asociación Mexicana de Criadores de Ganado Caprino de Registro. Field technicians routinely updated the goat national database by recording information from flocks participating in the performance-recording system. Information on animal identification number, parents, birth date, sex, breed, and farm of origin were used to undertake pedigree analyses using the ENDOG program (version 4.8). This paper presents a pedigree data file, tables and figures of characteristics of pedigree data, pedigree analyses, pedigree integrity, effective population size and genetic conservation index. The data can be used to estimate other population parameters, to monitor the genetic diversity of the Boer and Nubian goat breeds in Mexico, and also to design balanced breeding programs, maintaining genetic variation at reasonable levels and maximizing genetic progress in these populations.202

Study by optical spectroscopy and molecular dynamics of the interaction of acridine-spermine conjugate with DNA

International audienc

Comparative analysis of a batch and continuous fluidized bed reactors for thermocatalytic decomposition of methane:A CFD-DEM-MGM approach

ThermoCatalytic Decomposition of methane (TCD) has shown great potential for synthesis of valuable carbon nanomaterials as well as hydrogen production, however due to the importance of the phenomena operating at different scales, it is a complex process to model and predict. During the TCD process methane is decomposed to hydrogen gas and solid carbon. Carbon is accumulated on the catalyst particle and leads to larger but less active catalyst particles. In this study, a Computational Fluid Dynamics-Discrete Element Method-Multi Grain Model (CFD-DEM-MGM) was employed to investigate two catalytic fluidized bed reactors for TCD with the same dimensions. Case-1 involved a batch of catalyst particles staying in the reactor during the process, while Case-2 featured a continuous reactor with removal of catalyst particles from the bottom and the introduction of fresh particles from the side. Results showed that the continuous reactor had lower catalyst particle growth and reduced deactivation due to limited residence time, yet demonstrated higher carbon production and gas conversion. Case-1, with larger catalyst particles, experienced reduced bubble formation, while in Case-2 the continuous removal/introduction of particles enhanced solids mixing. Internal diffusion limitations affected reactor performance, emphasizing the CFD-DEM-MGM model’s potential for optimizing fluidized bed reactor design and gas-solid contacting in the TCD process.ThermoCatalytic Decomposition of methane (TCD) has shown great potential for synthesis of valuable carbon nanomaterials as well as hydrogen production, however due to the importance of the phenomena operating at different scales, it is a complex process to model and predict. During the TCD process methane is decomposed to hydrogen gas and solid carbon. Carbon is accumulated on the catalyst particle and leads to larger but less active catalyst particles. In this study, a Computational Fluid Dynamics-Discrete Element Method-Multi Grain Model (CFD-DEM-MGM) was employed to investigate two catalytic fluidized bed reactors for TCD with the same dimensions. Case-1 involved a batch of catalyst particles staying in the reactor during the process, while Case-2 featured a continuous reactor with removal of catalyst particles from the bottom and the introduction of fresh particles from the side. Results showed that the continuous reactor had lower catalyst particle growth and reduced deactivation due to limited residence time, yet demonstrated higher carbon production and gas conversion. Case-1, with larger catalyst particles, experienced reduced bubble formation, while in Case-2 the continuous removal/introduction of particles enhanced solids mixing. Internal diffusion limitations affected reactor performance, emphasizing the CFD-DEM-MGM model’s potential for optimizing fluidized bed reactor design and gas-solid contacting in the TCD process

Ignition and combustion development for high speed direct injection diesel engines under low temperature cold start conditions

Diesel engine cold start is an important issue for current technology at low (below 0 °C) temperatures and for future applications. The aim of this work is to develop a description of how, when and where does fuel spray ignition occur in a glow-plug assisted engine under simulated low temperature cold start conditions. In-cylinder pressure analysis is combined with high speed visualization in an optical engine. A pilot plus main injection strategy is used. Visualization results show that pilot ignition occurs in the vicinity of the glow plug, and strongly influences main combustion initiation. Main combustion starts from the pilot flame, and propagates to the rest of the combustion chamber showing a strong visible reaction zone. After end of main injection, the rapid leaning of the mixture suppresses the strong radiation, and OH radiation is observed to progress to the rest of the combustion chamber. The combustion process shows a strong scattering, which has been quantified by combustion parameters. At higher rail pressures scattering increases, which eventually inhibits combustion initiation. However, if ignition occurs at higher rail pressures, cycle performance is better.Authors thank the Spanish Ministry of Innovation and Science for the financial support through the project OPTICOMB (reference code: TRA2007-67961-C03-C01). Authors also thank Daniel Lerida Sanchez de las Heras for his outstanding work in the facility set-up and adaptation and for his support during the tests.Pastor Soriano, JV.; García Oliver, JM.; Pastor Enguídanos, JM.; Ramírez Hernández, JG. (2011). Ignition and combustion development for high speed direct injection diesel engines under low temperature cold start conditions. Fuel. 90(4):1556-1566. https://doi.org/10.1016/j.fuel.2011.01.008S1556156690

Influence of nozzle geometry on ignition and combustion for high-speed direct injection diesel engines under cold start conditions

Starting at low temperatures (below 0 °C) is an important issue for current and near future diesel engine technology. Low ambient temperature causes long cranking periods or complete misfiring in small diesel engines and, as a consequence, an increased amount of pollutant emissions. This paper is devoted to study the influence of nozzle geometry on ignition and combustion progression under glow-plug aided cold start conditions. This study has been carried out in an optically accessible engine adapted to reproduce in-cylinder conditions corresponding to those of a real engine during start at low ambient temperature. The cold start problem can be divided in two parts in which nozzle geometry has influence: ignition and main combustion progress. Ignition probability decreases if fuel injection velocity is increased or if the amount of injected mass per orifice is reduced, which is induced by nozzles with smaller hole diameter or higher orifice number, respectively. Combustion rates increase when using nozzles which induce a higher momentum, improving mixture conditions. For these reasons, the solution under these conditions necessarily involves a trade-off between ignition and combustion progress.Authors thank the Spanish Ministry of Innovation and Science for the financial support through the project OPTICOMB (reference code: TRA2007-67961-C03-C01). Authors also thank Daniel Lerida Sanchez de las Heras for his outstanding work in the facility set-up and adaptation and for his support during the tests.Desantes Fernández, JM.; García Oliver, JM.; Pastor Enguídanos, JM.; Ramírez Hernández, JG. (2011). Influence of nozzle geometry on ignition and combustion for high-speed direct injection diesel engines under cold start conditions. Fuel. 90(11):3359-3368. https://doi.org/10.1016/j.fuel.2011.06.006S33593368901

Metastable liquid lamellar structures in binary and ternary mixtures of Lennard-Jones fluids

We have carried out extensive equilibrium molecular dynamics (MD) simulations to investigate the Liquid-Vapor coexistence in partially miscible binary and ternary mixtures of Lennard-Jones (LJ) fluids. We have studied in detail the time evolution of the density profiles and the interfacial properties in a temperature region of the phase diagram where the condensed phase is demixed. The composition of the mixtures are fixed, 50% for the binary mixture and 33.33% for the ternary mixture. The results of the simulations clearly indicate that in the range of temperatures $78 < T < 102 ^{\rm o}$K, --in the scale of argon-- the system evolves towards a metastable alternated liquid-liquid lamellar state in coexistence with its vapor phase. These states can be achieved if the initial configuration is fully disordered, that is, when the particles of the fluids are randomly placed on the sites of an FCC crystal or the system is completely mixed. As temperature decreases these states become very well defined and more stables in time. We find that below $90 ^{\rm o}$K, the alternated liquid-liquid lamellar state remains alive for 80 ns, in the scale of argon, the longest simulation we have carried out. Nonetheless, we believe that in this temperature region these states will be alive for even much longer times.Comment: 18 Latex-RevTex pages including 12 encapsulated postscript figures. Figures with better resolution available upon request. Accepted for publication in Phys. Rev. E Dec. 1st issu

Identification of New Wheat Genes for Durable Resistance of Adult Plants to Yellow Rust (Puccinia striiformis Westend. f. sp. Ericks)

Yellow rust is a wheat disease caused by Puccinia striiformis, this pathogen causes economic losses in susceptible materials, which represent up to 70% of wheat varieties. Currently, the incorporation of genetic resistance through molecular tools, is a process used in the generation of new varieties resistant to this pathogen. A strategy employed to identify genes involved in the resistance to yellow rust is to screen differential EST obtained by suppressive subtractive hybridization. In this research, cDNA was extracted from healthy and inoculated plants from the resistant line V-26 from INIFAP. A set of 200 differentially expressed EST were cloned and sequenced, and 31 of them were selected for expression profile analysis by RT-PCR; additionally, with the aim of validate RT-PCR results, five genes were selected for RT-qPCR analysis in genotypes inoculated by P. striiformis. The results showed high levels of expression of selected genes in genotypes classified as resistant in the field conditions (21, 143, 230, 242, 261 and 277), while in the susceptible genotype 16, few genes were induced by the rust. Expression profiles confirmed significant differences between resistant and susceptible lines