Time reversibility of the discrete element method

An algorithm is presented for discrete element method simulations of energy-conserving systems of frictionless, spherical particles in a reversed-time frame. This algorithm is verified, within the limits of round-off error, through implementation in the LAMMPS code. Mechanisms for energy dissipation such as interparticle friction, damping, rotational resistance, particle crushing, or bond breakage cannot be incorporated into this algorithm without causing time irreversibility. This theoretical development is applied to critical-state soil mechanics as an exemplar. It is shown that the convergence of soil samples, which differ only in terms of their initial void ratio, to the same critical state requires the presence of shear forces and frictional dissipation within the soil system.     

Crystallization in Confinement

Many crystallization processes of great importance, including frost heave, biomineralization, the synthesis of nanomaterials, and scale formation, occur in small volumes rather than bulk solution. Here, the influence of confinement on crystallization processes is described, drawing together information from fields as diverse as bioinspired mineralization, templating, pharmaceuticals, colloidal crystallization, and geochemistry. Experiments are principally conducted within confining systems that offer well-defined environments, varying from droplets in microfluidic devices, to cylindrical pores in filtration membranes, to nanoporous glasses and carbon nanotubes. Dramatic effects are observed, including a stabilization of metastable polymorphs, a depression of freezing points, and the formation of crystals with preferred orientations, modified morphologies, and even structures not seen in bulk. Confinement is also shown to influence crystallization processes over length scales ranging from the atomic to hundreds of micrometers, and to originate from a wide range of mechanisms. The development of an enhanced understanding of the influence of confinement on crystal nucleation and growth will not only provide superior insight into crystallization processes in many real-world environments, but will also enable this phenomenon to be used to control crystallization in applications including nanomaterial synthesis, heavy metal remediation, and the prevention of weathering.     

HarVis: An integrated social media content analysis framework for YouTube platform

YouTube (owned by Google Inc.) is arguably among most popular social media platforms used by millions across the globe. It provides an ever-growing, unique and rich source of content which presents new opportunities and challenges for information discovery and analysis. It is pertinent to explore and understand a topic via YouTube content to discover interesting information about public opinions and sentiments. This paper presents an integrated framework to facilitate the acquisition, storage, management, processing, and visualization of relevant content with the objective to assist in such analysis. It not only collects a significant portion of content, relevant to a given topic, in short time but also offers tools for visual exploratory analysis such as; (i) temporal evolution, (ii) vocabulary network, (iii) authors relative popularity and influence (iv) categories and (v) user communities and influencers. The utility and effectiveness is demonstrated through content analysis of a famous YouTube entertainment topic, the “Gangnam Style”.     

Going Private in Public: A study on shift in behavioral trend using Facebook

The growth of social media has open a new dimension of research in the domain of human Psychology. The data generated by virtue of various available social media platforms is enormous, dynamic, unstructured, imprecise and most of the time uncertain. Facebook has emerged as one of the most successful media of social interaction and thus, contributing a lot to understand various aspects of human behavior. In this paper, a specific and crucial aspect of human nature is being explored- “Going Private in Public”. This aspect deals with some unexploited trend of human psychology and the research work presented in this paper is planned such as to investigate the data that eventually helps to understand this aspect to a great extent. A questionnaire to capture some behavioral trends of Facebook user was designed and filled up using both online and offline mode. The questionnaire included sets of non-identifying demographic questions, Facebook Intensity scale, Social and Emotional Loneliness Scale for Adult, Perceived Stress Scale and NEO-PI-R model. Filling of the forms was made voluntarily and anonymously to avoid any biasing. A total of 312 responses were received and analyzed using Independent-Sample t-test, Cronbach's alpha test, Exploratory factor analysis, and MANOVA etc.     

Chasing real-time interaction in new media: towards a new theoretical approach and definition

‘Real-Time’ is one of the most frequent concepts used referring to digital media. Despite it is commonly related to immediate feedback, it is not clear when it happens and what its characteristics are, especially in current digital interfaces. Although real-time has been written about very extensively in the context of Human Computer Interaction and Computational Systems, there are few studies evaluating the key features of real-time interaction in other domains. This article attempts to address this situation by proposing a new approach to the concept of real-time interaction driving the analysis of this topic into paradigmatic cases studies in new media, video games and digital artworks. This new analysis reveals several specific facets that allow us to identify new factors in the understanding of this fuzzy concept. Finally, the article proposes a new definition of ‘real-time interaction’ based on the findings in the context of new media practices.     

Simulation of forced convection in non-Newtonian fluid through sandstones

Numerical simulation is carried out to study forced convection in non-Newtonian fluids flowing through sandstones. Simulation is carried out using lattice Boltzmann method (LBM) for both shear-thinning and shear-thickening, by varying the power law index from 0.5 to 1.5 in Carreau–Yasuda model. Parameters involved in LBM and Carreau model are identified to achieve numerical convergence. Permeability and porosity are varied in the range of 10^?10–10^?6 and 0.1–0.7, respectively, to match actual geometrical properties of sandstone. Numerical technology is validated by establishing Darcy's law by plotting the graph between velocity and pressure gradient. Consequently, investigation is carried out to study the influence of material properties of porous media on flow properties such as velocity profiles, temperature profiles, and Nusselt number.     

数字媒体艺术在现代广告设计中的应用

目的探究数字媒体艺术在现代广告设计中的应用原则及方式。方法以数字媒体艺术为切入点,结合真实、创意、情感、系统等原则,对数字媒体艺术与现代广告设计的结合应用进行探索,并分别介绍数字媒体艺术在影视广告设计、户外广告设计及其他动态广告设计中的具体应用。结论数字媒体艺术与现代广告设计的结合,能够进一步丰富现代广告设计的内涵,提升设计质量,同时能够在一定程度上促进数字媒体艺术的发展和完善,实现共同提高。     

Simulations of flow through fluid/porous layers by a characteristic‐based method on unstructured grids

An upwind characteristic‐based finite volume method on unstructured grids is employed for numerical simulation of incompressible laminar flow and forced convection heat transfer in 2D channels containing simultaneously fluid layers and fluid‐saturated porous layers. Hydrodynamic and heat transfer results are reported for two configurations: the first one is a backward‐facing step channel with a porous block inserted behind the step, and the second one is a partially porous channel with discrete heat sources on the bottom wall. The effects of Darcy numbers on heat transfer augmentation and pressure loss were investigated for low Reynolds laminar flows. The results demonstrate the accuracy and robustness of the numerical scheme proposed, and suggest that partially porous insertion in a channel can significantly improve heat transfer performance with affordable pressure loss. Copyright © 2001 John Wiley & Sons, Ltd.     

非饱和土地基的三维非轴对称动力响应

考虑土颗粒、孔隙流体的压缩性以及各相物质间的黏性、惯性耦合,采用Bishop有效应力公式和毛管压力函数的V-G模型,建立了非饱和土的动力控制方程.通过引入位移函数,并利用Cauchy-Reimann条件,在直角坐标系下将非饱和土的波动方程进行解耦,进而采用双重Fouricr变换,求得了位移和应力在变换域上的一般解.结合...