A5029776068- Advanced Thermodynamics and Statistical Mechanics
- nanoparticles nucleation surface interactions
- Atmospheric chemistry and aerosols
- Advanced Chemical Physics Studies
- Statistical Mechanics and Entropy
- Spectroscopy and Quantum Chemical Studies
- Crystallization and Solubility Studies
- Quantum Mechanics and Applications
- Atmospheric aerosols and clouds
- Quantum Information and Cryptography
- Nuclear Structure and Function
- Phase Equilibria and Thermodynamics
- Theoretical and Computational Physics
- Nuclear Materials and Properties
- Complex Systems and Time Series Analysis
- stochastic dynamics and bifurcation
- Atmospheric Ozone and Climate
- RNA Research and Splicing
- Diamond and Carbon-based Materials Research
- Material Dynamics and Properties
- Calcium Carbonate Crystallization and Inhibition
- Force Microscopy Techniques and Applications
- thermodynamics and calorimetric analyses
- Quantum Chromodynamics and Particle Interactions
- Graphene research and applications
University College London
2015-2024
London Centre for Nanotechnology
2015-2024
University of Oxford
1988-1996
Ricardo AEA (United Kingdom)
1991-1996
Helsinki Institute of Physics
1994
University of Helsinki
1994
Research Complex at Harwell
1988-1992
United Kingdom Atomic Energy Authority
1989-1990
Universidad Autónoma Metropolitana
1987
The total entropy production and its three constituent components are described both as fluctuating trajectory-dependent quantities averaged contributions in the context of continuous Markovian dynamics, by stochastic differential equations with multiplicative noise, systems odd even coordinates respect to time reversal, such dynamics full phase space. Two these obey integral fluctuation theorems thus rigorously positive mean Jensen's inequality. third, however, is not furthermore cannot be...
The nucleation theorems relate the temperature and supersaturation dependence of rate droplets from a metastable vapor phase to properties critical molecular cluster, size that is approximately equally likely grow or decay. They are derived here using combination statistical mechanics cluster population dynamics, an arbitrary model definition. employed test validity classical theory homogeneous its ``internally consistent'' form. It found for these models incorrect, it emerges this occurs...
The total entropy production of stochastic systems can be divided into three quantities. first corresponds to the excess heat, while second two comprise housekeeping heat. We denote these components transient and generalized heat we obtain an integral fluctuation theorem for latter, valid all Markovian dynamics. A previously reported formalism is obtained when stationary probability distribution symmetric variables that are odd under time reversal, which restricts consideration directional...
The test-area (TA) perturbation approach has been gaining popularity as a methodology for the direct computation of interfacial tension in molecular simulation. Though originally implemented planar interfaces, TA also used to analyze properties curved liquid interfaces. Here, we provide an interpretation method taking view that it corresponds change free energy under transformation spatial metric affine distortion. By expressing configurational configuration Taylor expansion distortion...
Abstract A conceptual framework to predict microphysical and optical properties of contrail particles within a wingspan behind the source aircraft is developed. Results from two decades observations numerical simulations are reviewed forming basis theoretical model development. The utilizes cloud theory applied dynamics thermodynamics jet exhaust plumes in upper tropospheric conditions. Droplet nuclei include soot emitted engines atmospheric entrained into plume. These precursor activate...
Kristen Fichthorn opened the discussion of introductory lecture by James De Yoreo: I noted that in your potential mean force (PMF) plots for various particle orientations, fluctuations occur such different orientations could be preferred at a fixed distance. Could this affect ag
Abstract We investigate the quantum Zeno effect (QZE) in spin 1/2, 1 and 3/2 open systems undergoing Rabi oscillations, revealing unexplored features for systems. The interact with an environment designed to perform continuous measurements of observable, driving stochastically towards one eigenstates corresponding operator. system-environment coupling constant represents strength measurement. Stochastic trajectories are generated by unravelling a Markovian Lindblad master equation using...
Modeling the evolution of a system using stochastic dynamics typically implies increasing subjective uncertainty in adopted state and its environment as time progresses, entropy production has been developed measure this change. In some situations, can be described an Itô process, but mathematical difficulties emerge if diffusion phase space happens to restricted subspace lower dimension. This situation arise there are constants motion, for example, or more generally when functions...
The Dillmann-Meier theory of homogeneous nucleation in its original form contains an inconsistency which can be removed by taking into account imperfect vapor effects. predicted rates the corrected model are much larger than those model. Agreement between and experiment restored, however, a revised parametrization model, involving only one free parameter \ensuremath{\tau}. Models suggest range possible values for this parameter, with \ensuremath{\tau}=0 yielding good agreement predictions...
The rapid (<1 ms) transport of biological material to and from the cell nucleus is regulated by nuclear pore complex (NPC). At core NPC a permeability barrier consisting intrinsically disordered phenylalanine-glycine nucleoporins (FG Nups). Various types receptors (NTRs) facilitate partitioning in FG Nup assembly, overcoming their affinity Nups, comprise significant fraction proteins barrier. In previous work (Zahn et al., 2016), we revealed universal physical behaviour experimentally...
Two nucleation theorems are proved using small system thermodynamics. The first is well known and has been used before to determine the number of molecules in critical nucleus controlling droplets from supersaturated vapours. second appears be new, relates temperature dependence rate excess internal energy cluster. An analysis measured homogeneous rates can therefore provide size, energy, free entropy cluster, which should important guidance for construction theoretical models process. This...
Polymer-coated pores play a crucial role in nucleo-cytoplasmic transport and number of biomimetic nanotechnological applications. Here we present Monte Carlo Density Functional Theory approaches to identify different collective phases end-grafted polymers nanopore study their relative stability as function intermolecular interactions. Over range system parameters that is relevant for nuclear pore complexes, observe two distinct phases: one with the bulk condensed at wall pore, other along...
A combined adhesion-roughness model of friction, originally developed for contact between a narrow slider and single asperity, is applied to the case multiple asperity rough surfaces. An analytical model, based on Greenwood-Williamson contact, leads simple roughness-dependent expression friction coefficient. For elastic deformation at each point, contribution due roughness half that suggested by analysis. When largely plastic, contribution. The reduction mainly cancellation when forces...
This undergraduate textbook provides a statistical mechanical foundation to the classical laws of thermodynamics via comprehensive treatment basics thermodynamics, equilibrium mechanics, irreversible and mechanics non-equilibrium phenomena. © 2013 John Wiley & Sons, Ltd.
Nuclear transport receptors (NTRs) mediate nucleocytoplasmic via their affinity for unstructured proteins (polymers) in the nuclear pore complex (NPC). Here, we have modeled effect of NTRs on polymeric structure nanopore confinement NPC central conduit. The model explicitly takes into account inter- and intramolecular interactions, as well finite size (∼20% channel diameter). It reproduces various proposed scenarios structure, ranging from a polymer condensate (selective phase) to brushlike...
The complete mechanism behind the thermal decomposition of ethylene (C<sub>2</sub>H<sub>4</sub>) on Ir(111), which is first step graphene growth, established for time employing a combination experimental and theoretical methods.
Abstract Calcium carbonate biomineralization is remarkable for the ability of organisms to produce calcite or aragonite with perfect fidelity, where this commonly attributed specific anionic biomacromolecules. However, it proven difficult mimic behavior using synthetic biogenic organic molecules. Here, shown that cationic polyamines ranging from small molecules large polyelectrolytes can exert exceptional control over calcium polymorph, promoting nucleation at extremely low concentrations...
Incorporation of guest additives within inorganic single crystals offers a unique strategy for creating nanocomposites with tailored properties. While anionic have been widely used to control the properties crystals, their effective incorporation remains key challenge. Here, we show that cationic are an excellent alternative synthesis nanocomposites, where they shown deliver exceptional levels up 70 wt % positively charged amino acids, polymer particles, gold nanoparticles, and silver...
We study a single cluster of Lennard-Jones atoms using novel and physically transparent Monte Carlo simulation technique. compute the canonical ensemble averages grand growth decay probabilities cluster, identify critical size for which are equal. The internal energy different values temperature chemical potential, used together with nucleation theorems to predict behavior rate as function these parameters. Our results agree those found in literature, roughly correspond predictions classical...
We describe a modification of the Dillmann–Meier theory homogeneous nucleation which removes an inconsistency within original model. The predicted rates corrected model are much larger than those also point out that predictions independent one input parameters.
For the analysis of release fission product aerosols from reactor cores in a severe accident, it is necessary to understand process homogeneous nucleation droplets supersaturated vapour, including dependence on system pressure, which can vary greatly depending type accident. A model effect carrier gas presented, based changes energy distribution nucleating vapour molecule clusters induced by collisions with molecules. The rate altered since cluster decay strongly dependent. approach compared...