Search results for "Bolt"

2019

Abstract Heavy quarkonium related observables are very useful to obtain information about the medium created in relativistic heavy ion collisions. In recent years the theoretical description of quarkonium in a medium has moved towards a more dynamical picture in which decay and recombination processes are very important. In this talk we will discuss the equations that describe the evolution of the heavy quark reduced density matrix in different approximations, highlighting the color dynamics that is absent in the Abelian case, and we will study their semi-classical limit. This will allow us to obtain stochastic equations (similar to Langevin or Boltzmann equations) that can be useful to obt…

An implicitly parallel EDA based on restricted boltzmann machines

2014

We present a parallel version of RBM-EDA. RBM-EDA is an Estimation of Distribution Algorithm (EDA) that models dependencies between decision variables using a Restricted Boltzmann Machine (RBM). In contrast to other EDAs, RBM-EDA mainly uses matrix-matrix multiplications for model estimation and sampling. Hence, for implementation, standard libraries for linear algebra can be used. This allows an easy parallelization and leads to a high utilization of parallel architectures. The probabilistic model of the parallel version and the version on a single core are identical. We explore the speedups gained from running RBM-EDA on a Graphics Processing Unit. For problems of bounded difficulty like …

Observation of novel oxygen⋯oxygen interaction in supramolecular assembly of cobalt(III) Schiff base complexes: a combined experimental and computati…

2015

Two mononuclear cobalt(III) Schiff base complexes with azide [Co(L)(N3)(L0 )] (1) and [Co(L)(N3)(L00)] (2) {where HL ¼ 1-((2-(diethylamino)ethylimino)methyl)naphthalene-2-ol, HL0 ¼ 2-hydroxy-1-naphthaldehyde and HL00 ¼ acetylacetone} have been synthesized and characterized by elemental analysis, IR and UV-Vis spectroscopy and single crystal X-ray diffraction studies. Both complexes show mononuclear structures with azide as terminal coligand. Structural features have been examined in detail that reveal the formation of interesting supramolecular networks generated through non-covalent forces including hydrogen bonding, C–H/H–C and C–H/p interactions. These interactions have been studied ener…

Not Another Set of Nuts and Bolts

2011

The Boltzmann factor through experiments and simulations

2009

The Boltzmann factor is at the basis of a great amount of thermodynamic and statistical physics, both classical and quantum. It describes the behaviour of natural systems that are exchanging energy with the environment. However, why does the expression have this specific form? The Feynman Lectures on Physics justifies it heuristically by reference to the “exponential atmosphere” example. Thermodynamics textbooks usually give a more or less complete explanation that mainly involves the mathematical analysis, where it is hard to see the logic flow. Moreover, the necessary mathematics is not at the level of high school or college students’ preparation. Here we present an experiments and a simu…

Tre esperimenti per un approccio unificante al fattore di Boltzmann

2010

La comprensione del fattore di Boltzmann, alla base della descrizione di molti sistemi naturali sia classici che quantistici, richiede una trattazione matematica raramente alla portata degli studenti dei primi anni dei corsi universitari ad indirizzo scientifico. Viene qui discusso un approccio didattico per la sua introduzione a studenti che si trovano ad affrontare, per la prima volta, lo studio della meccanica statistica. L’approccio si basa sull’analisi di tre semplici esperimenti, condotti utilizzando apparati sperimentali sia di tipo tradizionale che MBL (Microcomputer Based Laboratory), finalizzati a evidenziare la caratteristica unificante del fattore di Boltzmann nella descrizione …

Die Vierte Welt in Berlin: a minor art space in THE CAPITAL OF CREATIVITY

2019

Portraying an alternative theatre space in Berlin, called "Vierte Welt", this article reflects upon the recent changes in the 'spirit of Capitalism' (Boltansik / Chiapello) that has shaped the old and new German capital as an alledged contemporary Eden of creativity and artistic critique.

Qualitative characterisation of effective interactions of charged spheres on different levels of organisation using Alexander’s renormalised charge a…

2005

Abstract Effective interactions are conveniently determined from experimental or numerical data by fitting a Debye–Huckel potential with an effective charge Z ∗ and an effective electrolyte concentration c ∗ as free parameters. In this contribution we numerically solved the Poisson–Boltzmann equation to obtain the so-called renormalised charge Z PBC ∗ . For sufficiently large bare charge Z one finds a saturation of Z ∗ which scales as Z ∗ = A a / λ B , where a is the particle radius, λ B the Bjerrum length and A a proportionality factor of order (8–10). The saturation value increases with increased total micro-ion concentration and shows a shallow minimum as a function of packing fraction. …

High-order regularization in lattice-Boltzmann equations

2017

A lattice-Boltzmann equation (LBE) is the discrete counterpart of a continuous kinetic model. It can be derived using a Hermite polynomial expansion for the velocity distribution function. Since LBEs are characterized by discrete, finite representations of the microscopic velocity space, the expansion must be truncated and the appropriate order of truncation depends on the hydrodynamic problem under investigation. Here we consider a particular truncation where the non-equilibrium distribution is expanded on a par with the equilibrium distribution, except that the diffusive parts of high-order nonequilibrium moments are filtered, i.e., only the corresponding advective parts are retained afte…

Self-Assembly of Polymeric Particles in Poiseuille Flow: A Hybrid Lattice Boltzmann/External Potential Dynamics Simulation Study

2017

We present a hybrid simulation method which allows one to study the dynamical evolution of self-assembling (co)polymer solutions in the presence of hydrodynamic interactions. The method combines an established dynamic density functional theory for polymers that accounts for the nonlocal character of chain dynamics at the level of the Rouse model, the external potential dynamics (EPD) model, with an established Navier–Stokes solver, the Lattice Boltzmann (LB) method. We apply the method to study the self-assembly of nanoparticles and vesicles in two-dimensional copolymer solutions in a typical microchannel Poiseuille flow profile. The simulations start from fully mixed systems which are sudd…