The free Lie, right, and left Leibniz algebras are obtained as quotients of the free nonassociative algebra by suitable ideals. In this article, we prove some remarkable properties of these ideals. 相似文献
A series of iPP/SiO2 nanocomposites, containing 1, 2.5, 5, 7.5, and 10 wt.‐% fumed silica nanoparticles, were prepared by melt mixing in a twin screw co‐rotating extruder. The effect of different extrusion parameters was evaluated. The size of aggregates increased with increase in SiO2 content and repetition of the mixing process improved the filler's dispersion. A similar effect was also exhibited by either increasing the rotor speed or the mixing temperature, with the latter being more pronounced at the ranges studied. The mechanical properties of the prepared nanocomposites were evaluated and various models used to explain the observed enhancements. However, only the three‐phase model could provide some correlation with the experimental results. All nanocomposites displayed lower permeability to gases.
This paper examines a model of a serial flow line with two workstations and an intermediate buffer. Each workstation consists of multiple unreliable parallel machines which are not necessarily identical, viz., the processing times, failure times and repair times of the parallel machines at each workstation are assumed to be exponentially distributed with non-identical mean rates. The system under consideration is solved via exact Markovian analysis. More specifically, a recursive algorithm that generates the transition matrix for any value of the intermediate buffer capacity is developed and all possible transition equations are derived and solved analytically. Once the transition equations are solved the performance measures of the model under consideration can be easily evaluated. This model may be used as a decomposition block for solving larger flow lines with parallel unreliable machines at each workstation. 相似文献
The phase behavior and associated pattern formation of two-dimensional systems of hard disks decorated with amphiphilic coronae (Janus disks) are studied by means of Monte Carlo computer simulations. A primitive interaction potential that captures the essential interparticle interactions is introduced. Despite its simplicity, the system exhibits a very rich phase polymorphism. Apart from the isotropic phase and depending upon the coronal thickness, the simulated systems self-organize in a number of two-dimensional mesophases of various symmetries exhibiting a variety of novel patterns. The results of these simulations suggest that 2D Janus particles are promising candidates for bottom-up design of precise two-dimensional templates. 相似文献
An enhanced metamaterial absorber based on the circumscribed-cross resonator is introduced in this paper. The new structure is polarization-independent, due to the symmetry of its unit cell, and is proven efficient for the attenuation of obliquely incident waves. The absorption mechanism is thoroughly investigated and is found to be mainly related to the losses of the dielectric substrate. Furthermore, by exploiting the scalability property of metamaterials, the operational bandwidth of our design can be drastically improved by placing unit cells with properly scaled resonators adjacent to each other. In this context, various combinations of three, four, and nine unit cells that can increase the full width at half maximum up to as much as 11.18?%, are developed. The overall performance of the proposed configurations is deemed promising for the realization of microwave metamaterial absorbers for several practical applications. 相似文献
Large Eddy Simulations for two flows separating from a two-dimensional hump in a duct are reported and discussed. The flows
differ through the presence or absence of a synthetic slot-jet injected in a sinusoidal manner, i.e. at zero net mass-flow
rate, close to the location of separation and intended to reduce (“control”) the extent of the separated region. Results reported
include instantaneous visualisations, pre-multiplied spectra, wall-pressure distributions, streamfunction fields and profiles
of velocity and second moments. For both flows, agreement between the simulations and the experimental results is generally
good, especially in respect of the overall control effectiveness of the synthetic jet, despite the use of an approximate wall
treatment bridging the viscous sublayer. Proper Orthogonal Decomposition of the velocity field is used to study structural
features, and this shows that the most energetic mode in the base flow is representative of large streamwise vortices in the
separated region, while in the controlled flow, most of the energetically dominant modes are associated with large spanwise
vortices. 相似文献