Morphology/behaviour relationship of nanocomposites based on natural rubber/epoxidized natural rubber blends

In order to analyze the effect of an epoxidized natural rubber (ENR) and filler treatment on the morphology and behavior of natural rubber (NR) nanocomposites, blends of these polymers have been prepared. The nature and extent of the clay dispersions in the filled samples were evaluated by X-ray diffraction. In the presence of ENR, an exfoliated structure was obtained which suggests that enough rubbery polymer was incorporated into the interlayer spacing. The effect of clay in rubber compounds was analyzed through rheological, mechanical and swelling characterization. A sensible improvement in the nanocomposite properties was observed by the addition of organoclay. It has been deduced that the properties of the compounds strongly depend on the extent of the silicate nanolayers dispersion into the rubber matrices as well as on the organoclay type and elastomer compatibility.     

Effect of Magnetotactic bacteria on the susceptibility in Chinese loess–paleosol sequences

A simulated experiment of Magnetotactic bacteria (MB) effect on susceptibility in the samples from the 5th to 6th loess layers (L₅–S₅–L₆) in Xifeng and Duangjiapo sections was performed. It is demonstrated that MB can increase the susceptibility of the samples and promote newly produced magnetic minerals from paleosol layers under the suitable condition. The tiny magnetic particles and arranged as a chain in the minerals less than 30 μm were found in the paleosol sample of Duangjiapo section.     

Interpretation of the morphology and crystallography of precipitate γ1-Ti4Nb3Al9 in L10-TiAl(Nb)-based intermetallics by invariant line theory

The coherent precipitate γ₁-Ti₄Nb₃Al₉ in the Nb-modified TiAl-based intermetallic compound with a nominal composition of Ti–48 at% Al–10 at% Nb was investigated by transmission electron microscopy. The crystallographic and morphologic characteristics of the precipitating phase have been calculated based on invariant line theory. It is revealed that in the γ-TiAl(Nb)/γ₁-Ti₄Nb₃Al₉ couples, both the morphological and crystallographical characteristics of the precipitate γ₁-Ti₄Nb₃Al₉ could be predicted by the three-dimensional phase transformation invariant line model. The needle direction of [001] at the early stage for coherent precipitate γ₁-Ti₄Nb₃Al₉ and [111] for equilibrium phase γ₁-Ti₄Nb₃Al₉ have both been explained well. The characterization of morphology and crystallography of the precipitate reaction in γ-TiAl/γ₁-Ti₄Nb₃Al₉ system sustain the postulate that precipitates are bounded by unrotated planes (eigenplanes) when three real eigenvalues exist.     

Visual motion ambiguities of a plane in 2-D FS sonar motion sequences

Sonar is the most common imaging modality in underwater, and high-resolution high data rate 2-D video systems have been emerging in recent years. As for visually guided terrestrial robot navigation and target-based positioning, the estimation of 3-D motion by tracking features in recorded 2-D sonar images is also a highly desirable capability for submersible platforms. Additionally, theoretical results dealing with robustness and multiplicity of solution constitute important fundamental findings due to nature of sonar data, namely, high noise level, narrow field of view coverage, scarcity of robust features, and incorrect matches.This paper explores the inherent ambiguities of 3-D motion and scene structure interpretation from 2-D forward-scan sonar image sequences. Analyzing the sonar image motion transformation model, which depends on the affine components of the projective transformation (or homography) of two plane views, we show that two interpretations are commonly inferred. The true and spurious planes form mirror images relative to the zero-elevation plane of the sonar reference frame. Even under each of pure rotation or translation, a spurious motion exists comprising both translational and rotational components. In some cases, the two solutions share certain motion components, where the imaged surface becomes parallel to a plane defined by two of the sonar coordinate axes. A unique solution exists under the very special condition where the sonar motion aligns the imaged plane with the zero-elevation planes. We also derive the relationship between the two interpretations, thus allowing closed-form computation of both solutions.     

Effect of additives on formation of natural gas hydrate

The formation of natural gas hydrate (NGH) is studied in this work. Kinetics data of hydrate formation with no agitation were collected at various concentrations of the aqueous solutions with different additives such as alkylpolyglucside, sodium dodecyl benzene sulfonate and potassium oxalate monohydrate. Various kinds of additive increased the formation rates of NGH and its storage capacity and reduced the induction time of NGH formation. Moreover, the storage capacity, the induction time and the hydrate formation rate were influenced by the concentration of the aqueous solution.     

高速公路收费站车辆能耗研究

车辆通过高速公路收费站时,需要减速或停车缴费,当车辆较多时,容易形成排队,产生大量延误,大大削弱了车辆的运行效率,增加了车辆的能耗,同时使得车辆尾气的排放量增加,严重污染了环境。本文使用排队论知识对收费站车辆排队与疏散情况进行分析,减少车辆的排队等候时间和驶离站口所需时间,以达到减少行车能耗的目的。最后,通过一个实例给出几种收费方式下的能耗,并给出了相应的分析和建议,可为高速公路收费方式和能耗研究提供一定的参考。     

TrajStat: GIS-based software that uses various trajectory statistical analysis methods to identify potential sources from long-term air pollution measurement data

Statistical analysis of air mass back trajectories combined with long-term ambient air pollution measurements are useful tools for source identification. Using these methods, the geographic information system (GIS) based software, TrajStat, was developed to view, query, and cluster the trajectories and compute the potential source contribution function (PSCF) and concentration weighted trajectory (CWT) analyses when measurement data are included.     

Stabilizing switching design for switched linear systems: A state-feedback path-wise switching approach

This paper addresses the problem of switching stabilization for discrete-time switched linear systems. Based on the abstraction-aggregation methodology, we propose a state-feedback path-wise switching law, which is a state-feedback concatenation from a finite set of switching paths each defined over a finite time interval. We prove that the set of state-feedback path-wise switching laws is universal in the sense that any stabilizable switched linear system admits a stabilizing switching law in this set. We further develop a computational procedure to calculate a stabilizing switching law in the set.     

Controlling the diffusionless Lorenz equations with periodic parametric perturbation

Diffusionless Lorenz equations (DLE) are a simple one-parameter version of the well-known Lorenz model, which was obtained in the limit of high Rayleigh and Prandtl numbers, physically corresponding to diffusionless convection. A simple control method is presented to control chaos by using periodic parameter perturbation in DLE. By using the generalized Melnikov method, the parameter conditions could be obtained to guide the controlled DLE to a low-periodic motion. Moreover, the existence conditions of periodic orbits and homoclinic orbits in the system are given. Some results of the numerical simulation are also explained clearly by a rigorous analysis.