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Ferrogels, i.e., magnetic nanoparticles immersed into a swollen polymer gel, are materials which combine the magnetic properties of a ferrofluid with the elastic properties of a hydrogel. This makes it possible to control their shape and elasticity by means of external magnetic fields. Magnetic gels are therefore considered for medical and technical applications such as actuation and drug delivery systems. In this paper, we focus on a special class of magnetic gels in which the magnetic nanoparticles act as the cross-linkers of the polymer network. Experimentally this is achieved by functionalizing the nanoparticles' surface such that the polymers can covalently bind to it. In this way, a coupling between the orientation of the nanoparticles and the polymer matrix is created. When an external magnetic field is applied to such a system, the magnetic particles align to the field, and due to the coupling between the nanoparticles' orientation and the gel matrix, a strain is exerted on the polymers. This leads to a shrinking of the gel as a whole. In this paper, we explain how to extend a two-dimensional simulation model for such a system (Soft Matter 8 (2012) 9923 [18] ) to three dimensions. We will show that, while an isotropic deformation was observed in the two-dimensional case, in three dimensions the gel shrinks anisotropically. This is due to the fact that orientational fluctuations of the nanoparticles are hindered in the direction perpendicular to an external magnetic field. [ABSTRACT FROM AUTHOR]

Based on the finite-time stability theory, this paper deals with finite-time synchronization for a class of fuzzy cellular neural networks with time-varying coefficients and proportional delays. Using differential inequality techniques and the analysis approach, we derive some new and useful sufficient conditions of finite-time synchronization for the addressed systems. Finally, an illustrative example with its numerical simulations is given to show the effectiveness of main results. [ABSTRACT FROM AUTHOR]

This paper describes the combination of a physical pollutant model IAPPEM with a time activity profile, to create an air pollutant personal exposure model. A previous study has already demonstrated the capability of IAPPEM in predicting indoor Particulate Matter (PM) concentrations in a residential environment. The present work investigates personal exposure variability between individuals and, doors opened vs closed scenarios, by examining the movements of four individuals through the same dwelling. The results of the simulations highlight the distinction between personal exposure and indoor concentrations, providing computational validation to well-documented experimental differences that exist between indoor concentrations and personal exposure. Using IAPPEM, personal exposure is calculated according to the percentage contribution from the time spent in each room, illustrating that the periods of presence, in relation to the times of indoor source emission, are as important as the durations spent in each room. This study provides a comparison between two approaches for evaluating personal exposure: a time-weighted average and a time activity profile. The results showed that a time-weighted averaged profile is a poor substitute when compared with personal exposure calculated based on a time activity profile, as, in each simulated scenario, exposures were under-predicted using the time-weighted approach, in some cases by up to 135%. [ABSTRACT FROM AUTHOR]

This paper presents the results from experiments and numerical simulations on the ballistic impact of 10 mm thick aramid fabric-epoxy composite laminates by a 7.62 mm armor piercing projectile at varying impact velocities. Post perforated residual velocity (RV), contact duration of projectile with the target and ballistic limit (BL) of composite were simulated using a finite element code HyperWorks-Radioss. Interaction of projectile with composite laminates was captured by high speed video. The predicted ballistic parameter from simulation compared well with the precision experimental results. The simulated energy and stress distribution during impact of projectile on composite laminate showed marked difference with variation in impact velocities (SV). The magnitude and duration of stress as well as the contact force was found to increase when projectile impacted at lower SV thus enhancing the extent of delaminating and the core damage area and the trend was reversed for higher SV. The findings corroborate the bullet inflicted damage of composite laminates experimentally determined by ultrasonic C-scan. [ABSTRACT FROM AUTHOR]

Screens are an important production unit in crushing plants. The performance of the screen is essential to the performance of the crushing plant. In this paper a mechanistic model of a banana screen is described and a novel model for screen deck configuration is presented. The developed model can be used for optimization of a screen so that it has the best possible performance with respect to different feeding conditions, in order to obtain a desired separation. The simulation results were compared to full scale test data and the conclusions from this comparison is that the screen model needs further parameters to handle the necessary screen deck configuration. An initial static model was derived to explain how the screen deck configuration will affect the screen efficiency. The modification of the screen deck parameters resulted in a better correlation both regarding size distribution and predicted capacity. [ABSTRACT FROM AUTHOR]