733 research outputs found
Adaptive Resolution Simulation of Liquid Water
We present a multiscale simulation of liquid water where a spatially adaptive
molecular resolution procedure allows for changing on-the-fly from a
coarse-grained to an all-atom representation. We show that this approach leads
to the correct description of all essential thermodynamic and structural
properties of liquid water.Comment: 4 pages, 3 figures; changed figure
Transport properties controlled by a thermostat: An extended dissipative particle dynamics thermostat
We introduce a variation of the dissipative particle dynamics (DPD)
thermostat that allows for controlling transport properties of molecular
fluids. The standard DPD thermostat acts only on a relative velocity along the
interatomic axis. Our extension includes the damping of the perpendicular
components of the relative velocity, yet keeping the advantages of conserving
Galilei invariance and within our error bar also hydrodynamics. This leads to a
second friction parameter for tuning the transport properties of the system.
Numerical simulations of a simple Lennard-Jones fluid and liquid water
demonstrate a very sensitive behaviour of the transport properties, e.g.,
viscosity, on the strength of the new friction parameter. We envisage that the
new thermostat will be very useful for the coarse-grained and adaptive
resolution simulations of soft matter, where the diffusion constants and
viscosity of the coarse-grained models are typically too high/low,
respectively, compared to all-atom simulations.Comment: 6 pages, 4 figure
Coupling atomistic and continuum hydrodynamics through a mesoscopic model: application to liquid water
We have conducted a triple-scale simulation of liquid water by concurrently
coupling atomistic, mesoscopic, and continuum models of the liquid. The
presented triple-scale hydrodynamic solver for molecular liquids enables the
insertion of large molecules into the atomistic domain through a mesoscopic
region. We show that the triple-scale scheme is robust against the details of
the mesoscopic model owing to the conservation of linear momentum by the
adaptive resolution forces. Our multiscale approach is designed for molecular
simulations of open domains with relatively large molecules, either in the
grand canonical ensemble or under non-equilibrium conditions.Comment: triple-scale simulation, molecular dynamics, continuum, wate
Coupling different levels of resolution in molecular simulations
Simulation schemes that allow to change molecular representation in a
subvolume of the simulation box while preserving the equilibrium with the
surrounding introduce conceptual problems of thermodynamic consistency. In this
work we present a general scheme based on thermodynamic arguments which ensures
thermodynamic equilibrium among the molecules of different representation. The
robustness of the algorithm is tested for two examples, namely an adaptive
resolution simulation, atomistic/coarse-grained, for a liquid of tetrahedral
molecules and an adaptive resolution simulation of a binary mixture of
tetrahedral molecules and spherical solutes
Digitalization and new media landscape
The article presents the phenomena of new communication technologies. It exposes the role of social media (Web 2.0) and sketches some global trends within the field of new media. It further outlines basic characteristics of traditional mass communication and consumption of media products, and as a counter-part presents interactive nature of a new media and the phenomena of user-generated media contents. The main focus of the article is the process of digitalization and its influence on important social system: media industry and production.
Digitalization and growth of social media have challenged the news industry, so the latter has to adjust its media production to the rising power of independent publishers on social media platforms, as well as to users, which became publishers themselves, the so-called prosumers. The process of multimedia production is described through various types of inclusion promised in the technological formats. This article also highlights the transformed “intimacy” of new media cultures, which presents further evidence of new, unstable, and to some respect blurring divisions between the public and private spheres of communication.
Several positive and negative consequences of digitalization on media landscape are enumerated. There are problems concerning transparency, accountability and professionalism of media production. Digital media has speed up the process of media production, journalists are faced with lack of time. Journalists as multitasking professionals are becaming the norm.
The article exposes social activities manifested on social media (networks). Social networks, such as Facebook and Twitter, are becoming news platforms for spreading information and news among users. Moreover, social media has become a powerful tool for publishers and journalists, as it enables them to augment or to keep their audience. Since social networks are usually used to accomplish interpersonal rather than professional goals, there is a risk of misperception of communication acts performed by journalists via social networks. Interaction via social networks is usually more personal, interactive, collaborative, but these characteristics are quite different from normative ideals, attributed to quality journalism.The article concludes with the question about possible solutions concerning further development of normative conceptions of journalism
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