A compromise solution for the multiobjective stochastic linear programming under partial uncertainty

This paper solves the multiobjective stochastic linear program with partially known probability. We address the case where the probability distribution is defined by crisp inequalities. We propose a chance constrained approach and a compromise programming approach to transform the multiobjective stochastic linear program with linear partial information on probability distribution into its equivalent uniobjective problem. The resulting program is then solved using the modified L-shaped method. We illustrate our results by an example.     

Understanding memristors and memcapacitors in engineering mechanics applications

Nonlinear Dynamics - A significant event happened for electrical engineering in 2008, when researchers at HP Labs announced that they had found “the missing memristor,” a fourth basic...     

The influence of gas phase velocity fluctuations on primary atomization and droplet deformation

The effects of grid-generated velocity fluctuations on the primary atomization and subsequent droplet deformation of a range of laminar liquid jets are examined using microscopic high-speed backlit imaging of the break-up zone and laser Doppler anemometry of the gas phase separately. This is done for fixed gas mean flow conditions in a miniature wind tunnel experiment utilizing a selection of fuels, turbulence-generating grids and two syringe sizes. The constant mean flow allows for an isolated study of velocity fluctuation effects on primary atomization in a close approximation to homogeneous decaying turbulence. The qualitative morphology of the primary break-up region is examined over a range of turbulence intensities, and spectral analysis is performed in order to ascertain the break-up frequency which, for a case of no grid, compares well with the existing literature. The addition of velocity fluctuations tends to randomize the break-up process. Slightly downstream of the break-up region, image processing is conducted in order to extract a number of metrics, which do not depend on droplet sphericity, and these include droplet aspect ratio and orientation, the latter quantity being somewhat unconventional in spray characterization. A turbulent Weber number $We^{\prime}$ which takes into account gas phase fluctuations is utilized to characterize the resulting droplet shapes, in addition to a mean Weber number <We _d>. Above a $We^{\prime}>0.05$ a clear positive relationship exists between the mean aspect ratio of droplets and the turbulent Weber number where $We^{\prime}$ is varied by altering all relevant variables including the velocity root mean square, the initial droplet diameter, the surface tension and the density.     

Synthesis and characterization of novel chelated dimethylamino lithium arylamide dimers: molecular structure of [1‐LiNPhCHPhCH2‐2‐NMe2C6H4]2

The reaction of 1‐NHPhCHPh‐2‐NMe₂C₆H₄ ( 1 ) and 1‐NHPhCHPhCH₂‐2‐NMe₂C₆H₄ ( 2 ) with n‐BuLi in diethyl ether gave the solvent‐free chelated dimethylamino lithium amides [1‐LiNPhCHPh‐2‐NMe₂C₆H₄]₂ ( 3 ) and [1‐LiNPhCHPhCH₂‐2‐NMe₂C₆H₄]₂ ( 4 ). The lithium amides 3 and 4 were characterized by ¹H, ⁷Li, and ¹³C NMR spectroscopy. A crystal structure determination was carried out on 4 , which is the first example of a structurally characterized solvent‐free dimeric chelated dimethylamino lithium arylamide with three‐coordinate lithium centers that contains a seven‐membered chelate ring. Copyright © 2003 John Wiley & Sons, Ltd.     

A Re-Configurable Test Apparatus for Complex Nonlinear Dynamic Systems

This paper reports the results of an analytical and experimental study to design, analyze, construct, test, and evaluate a re-configurable test-bed to allow the convenient performance of sophisticated experiments in a laboratory setting for investigating a broad category of important nonlinear, time-varying phenomena that are widely encountered in the applied mechanics field. The essential elements of the test apparatus include an electro-dynamic exciter that drives an oscillating mass whose restoring force is easily adjustable from one resembling a linear SDOF mass-spring-damper system with constant coefficients, to one that can represent systems with nonlinear elastic forces, to one that models systems possessing hysteretic properties with precisely-controlled time-varying characteristics. The apparatus design is economical to fabricate, convenient to manipulate, and it provides results that can be accurately replicated under repeated test combinations of system parameters and dynamic loads. The utility of the apparatus to provide an investigational tool for studying the dynamic response of systems with time-varying dry-friction forces that give rise to hysteretic phenomena is demonstrated. Sophisticated on-line system-identification techniques are used to estimate the parameters of reduced-order models that capture the dominant features of the physical model. It is shown that the apparatus under discussion is a useful research tool for investigators conducting studies in physics-based models of generic nonlinear dynamic systems.     

Possibilité de surstructures d'lnterface

On a simple model of an interface, obtained by coupling along two (001) surfaces two semi-infinite simple cubic crystals having the same lattice parameter, we show that atomic superstructures may exist near an interface. We use for that central potentials between first and second nearest neighbours and calculate soft localized phonons at the interface.     

Étude des propriétés vibrationnelles des interfaces couche mince-substrat par la méthode des fonctions de green

We present a formalism based upon the Green functions method to study the vibrational properties of an interface between two crystals of variable thickness. Analytical expressions are obtained for the surface Green functions where we take into account the force constant variation in the surface plane. Applications are made in the cases of a free surface, stacking fault and film-substrate interface.