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[en] Development and introduction of nanotechnologies in the oil industry is one of the most pressing issues of the present times.For the first time in the world practice scientific-methodological basis and application practice of nanotechnologies in oil industry is developed on the basis of uniform, scientifically proven approach by taking into account the specificities of oil and gas industry.The application system of such nanotechnologies was developed in oil and gas production.Mathematical models of nanotechnological processes, i.e.chaos regulationand hyper-accidental process were offered. Nanomedium and nanoimpact on the well-layersystem was studied. Wide application results of nanotechnologies in SOCAR's production fields in oil and gas production are shown.Research results of NANOSAAon the basis of NANO + NANOeffect are described in the development.For the first time in world practice NANOOIL,NANOBITUMEN,NANOGUDRON' and NANOMAY' systems on the basis of machine waste oil in the drilling mud were developed for the application in oil and gas drilling. Original property, effect of super small concentrationsand nanomemoryin NANOOILand NANOBITUMENsystems was discovered.By applying NANOOIL,NANOBITUMENand NANOMAYsystems in the drilling process was discovered: the increase of linear speed, early turbulence, decrease of hydraulic resistance coefficient and economy in energy consumption.Hyper-accidental evaluation of mathematical expectation of general sum of values of the surface strain on the sample data is spelled out with the various experiment conditions. Estimated hyper-accidental value of the mathematical expectation allows us to offer practical recommendations for the development of new nanotechnologies on the basis of rheological parameters of oil.
[en] This paper is devoted to modeling of a two-cell DC/DC buck converter, to the analysis of its behavior and to the design of control methods that yield to improve its performances. Various numerical simulations and dynamical aspects of this system are illustrated in the time domain and in the parameter space. Without control, the system may present many undesirable behaviors such as sub-harmonics and chaotic oscillations. The proposed controllers are able to widen the stability range of the system. Optimum values of parameters giving rise to fast response while maintaining stable periodic behavior are given in closed form. However, it is detected that in a certain region of the parameter space, the stabilized periodic orbit may coexist with a chaotic attractor. Boundary between basins of attraction are obtained by means of numerical simulations.
[en] We study the characteristics of chaotic laser outputs in a diode laser pumped Nd : YAG laser with an intracavity KTP crystal. When the pumping power is low enough, the laser produces stable green light. As the pumping power increases, it comes to produce chaos through periodic outputs. This is one of the routes to chaos appearing in this laser system. The chaotic outputs of the laser are analyzed through correlation function.
[en] The study of natural circulation loops is a subject of special concern for the engineering design of advanced nuclear reactors, as natural convection provides an efficient and completely passive heat removal system. However, under certain circumstances thermal-fluid-dynamical instabilities may appear, threatening the reactor safety as a whole.On the other hand, fuzzy logic controllers provide an ideal framework to approach highly non-linear control problems. In the present work, we develop a software-based fuzzy logic controller and study its application to chaotic natural convection loops.We numerically analyse the linguistic control of the loop known as the Welander problem in such conditions that, if the controller were not present, the circulation flow would be non-periodic unstable.We also design a Taka gi-Sugeno fuzzy controller based on a fuzzy model of a natural convection loop with a toroidal geometry, in order to stabilize a Lorenz-chaotic behaviour.Finally, we show experimental results obtained in a rectangular natural circulation loop
[es]Los circuitos termofluidodinamicos de conveccion natural estan cobrando especial importancia en el diseno de reactores nucleares avanzados, debido a que la conveccion natural suministra un sistema eficiente de remocion de calor completamente pasivo.Sin embargo, bajo ciertas condiciones, estos sistemas presentan inestabilidades que pueden llegar a poner en riesgo la seguridad integral del reactor.Por otro lado, los controladores basados en logica difusa proveen un entorno ideal para atacar problemas de control altamente no lineales.En este trabajo desarrollamos un software que implementa un control basado en logica difusa, y estudiamos su aplicacion a loops de conveccion natural caoticos.Analizamos numericamente el control linguistico del loop conocido como el problema de Welander en condiciones tales que, de no existir el control, el caudal de circulacion presentaria un comportamiento inestable no periodico.Disenamos tambien un controlador difuso a partir de un modelo matematico de Takagi y Sugeno para un loop de conveccion natural en geometria toroidal para estabilizar un comportamiento caotico de Lorenz.Finalmente, mostramos resultados experimentales obtenidos en un loop rectangular de conveccion natural
[en] In this paper, an active vibration control method for nonlinear mechanical systems is discussed. The control forces are determined by using the future values of the system obtained by the short-term prediction method based on chaos theory. The authors call such a control method a predictive control method. This method is applied to a pendulum system forced by a sinusoidal torque at the supported point as a numerical example here. The equation of motion for the system becomes nonlinear one when the swing angle is large. The angular displacements near future are used to calculate the control forces. Particularly, the methods to get the optimal sampling period, the forward horizon and the backward horizon are presented here and the effectiveness of the methods are examined numerically
[en] Full text: Many dynamically diverse outputs, including chaotic output, can be obtained from semiconductor laser systems using various methods such as optical feedback, optoelectronic feedback or optical injection. Analysis of long time streams of the output power versus time from chaotic semiconductor lasers, recorded using a measurement bandwidth of up to 4 GHz, has shown time variation in the dynamical output from these systems when operated in a constant configuration. Such dynamics in the dynamics has not been reported previously and represents a new complexity in these complex systems. Copyright (2005) Australian Institute of Physics