735 research outputs found

    Rogue Quantum Harmonic Oscillations

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    We show the existence and investigate the dynamics and statistics of rogue oscillations (standing waves) generated in the frame of the nonlinear quantum harmonic oscillator (NQHO). With this motivation, in this paper, we develop a split-step Fourier scheme for the computational analysis of NQHO. We show that modulation instability excites the generation of rogue oscillations in the frame of the NQHO. We also discuss the effects of various parameters such as the strength of trapping well potential, nonlinearity, dissipation, fundamental wave number and perturbation amplitude on rogue oscillation formation probabilities

    Implementation of a Non-Metallic Reinforced Bridge Deck, Volume 1: Bond Behavior

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    The primary maintenance problem with bridges in Indiana has been deterioration of the concrete deck which is often related to corrosion of the reinforcing steel. While a corrosion protection system consisting of epoxy-coated reinforcement in combination with 2-1/2 in. of Class C concrete cover has been used in Indiana, research and experience have demonstrated that this system can be compromised. As an alternative solution to the corrosion problem in reinforced concrete, fiber reinforced polymer (FRP) bars which are corrosion resistant can be provided as reinforcement. This research was divided into two phases directed towards the implementation of a nonmetallic reinforced bridge deck. The first phase evaluated the bond strength of fiber reinforced polymer reinforcement with the goal of developing a design expression for the calculation of development and splice lengths. Forty-six glass FRP, carbon FRP, and steel reinforced concrete beams with unconfined tension lap splices were tested. The second phase consisted of the design, construction, and performance evaluation of a glass FRP bar reinforced concrete bridge deck. Based on this study, design recommendations are provided for the calculation of development and splice lengths of both FRP and steel reinforcement. Furthermore, the behavior of the FRP reinforced bridge deck is assessed and compared with its design assumptions. The findings of this study provide design tools and behavioral data that will assist in the future development and deployment of this technology

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    A Hybrid System for Well Test Analysis

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    Petroleum well test analysis is a tool for estimating the average properties of the reservoir rock. It is a classic example of an inverse problem. Visual examination of the pressure response of the reservoir to an induced flow rate change at a well allows the experienced analyst to determine the most appropriate model from a library of generalized analytical solutions. Rock properties are determined by finding the model parameters that best fit the observed data. This paper describes a framework for hybrid network to assist the analyst in selecting the appropriate model and determining the solution. The hybrid network design offers significant advantages by reducing training time and allowing incorporation of both symbolic and numeric data. The network structure is described and the advantages and disadvantages compared to previous approaches are discusse

    ISO 9164 heat loss in roof-wall sections

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    In the simple ISO 9164 calculation procedure for transmission heat loss coefficient, HT, it is unclear, and undefined for floor or roof-wall sections, how the parameters in the equations will be calculated. In this paper, a method is proposed for the calculation of ISO 9164 parameters for roof-wall sections. The results obtained by the proposed method for typical roof sections are compared with those obtained by the EN 832/EN 13789/EN ISO 14683 methods and with the L2D values from 2D analysis. A comparison of the floor and roof behaviour is realized using the results of the present and the previous works of the authors. The HT values obtained by the proposed model using the sum of qy through the beam are harmonised with the L2D for floors, which are significantly different from the L2D for roofs with parapet. The results indicate that the L2D values cited in EN 10211-1 are sensitive to the 2D heat flows for floor sections. However, the L2D is not sufficiently sensitive to heat flow from the beam to the parapet and the interactions between the zones within the beam section, whereas the proposed method is more sensitive to the 2D heat flows. © 2011 Academic Journals

    Microscopic examination of hot spots giving rise to nonlinearity in superconducting resonators

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    We investigate the microscopic origins of nonlinear rf response in superconducting electromagnetic resonators. Strong nonlinearity appearing in the transmission spectra at high input powers manifests itself through the emergence of jumplike features near the resonant frequency that evolve toward lower quality factor with higher insertion loss as the rf input power is increased. We directly relate these characteristics to the dynamics of localized normal regions (hot spots) caused by microscopic features in the superconducting material making up the resonator. A clear observation of hot-spot formation inside a Nb thin film self-resonant structure is presented by employing the microwave laser scanning microscope, and a direct link between microscopic and macroscopic manifestations of nonlinearity is established.Comment: 5 pages, 4 figure

    A Hierarchial Neural Network Implementation for Forecasting

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    In this paper, a hierarchical neural network architecture for forecasting time series is presented. The architecture is composed of two hierarchical levels using a maximum likelihood competitive learning algorithm. The first level of the system has three experts each using backpropagation and a gating network to partition the input space in order to map the input vectors to the output vectors. The second level of the hierarchical network has an expert using fuzzy ART for producing the correct trend coming from the first level. The experiments show that the resulting network is capable of forecasting the changes in the input and identifying the trends correctl
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