Using extensive molecular dynamics simulations, we have investigated the extensivity of the internal energy and entropy as well as the intensivity of temperature and pressure in small thermodynamic systems. Atomic systems consisting of n3 n = 2 3 10 argon-like particles interacting through the Lennard-Jones potential energy function have been studied. It is found that in small systems, contrary...

For the Sturm-Liouville operator L =L,: .VP+ -p” +pv one seeks to reconstruct the coefficient p from knowledge of the sequence of eigen-frequencies (Aj with LJ? =Ajn for some y j # 0). An implementable scheme is: for some N determine pnr so (approximately) pN has minimum norm with eigen-frequencies { A , . . . . .IN/ as given. This is the method ot’ ’generalised interpolation‘ and is shown to g...

This work represents an extended computational study of the Fermi-Pasta-Ulam experiment for the dynamical nature of energy transfer among normal modes. A 2D lattice system with 40 particles is placed on a torus, where each particle is allowed to interact with its six nearest neighbors under the Lennard-Jones potential force law. Trajectories of the particles are analyzed through a Fourier trans...

We consider the low-density equation of state of a fluid along its critical isotherm. An asymptotically consistent approximant is formed having the correct leading-order scaling behavior near the vapor-liquid critical point, while retaining correct low-density behavior as expressed by the virial equation of state. The formulation is demonstrated for the Lennard-Jones fluid, and models for heliu...

Main problem for Mycobacterium tuberculosis growth is time. This study evaluates the performance of Bact/Alert 3D system for isolates and identification of mycobacteria. 100 clinical specimens from the chest and tuberculosis department were included. All were positive by Lowenstein Jensen (LJ) media in different time. All samples were also tested by Bact/ALERT 3D system for time management stud...

Presented is an improved model for the prediction of phase equilibria and cage occupancy of CH4 and CO2 hydrate in aqueous systems. Different from most hydrate models that employ Kihara potential or Lennard-Jones potential with parameters derived from experimental phase equilibrium data of hydrates, we use atomic site-site potentials to account for the angle-dependent molecular interactions wit...

Using the inherent structure formalism originally proposed by Stillinger and Weber @Phys. Rev. A 25, 978 ~1982!#, we generalize the thermodynamics of an energy landscape that has an ideal glass transition and derive the consequences for its equation of state. In doing so, we identify a separation of configurational and vibrational contributions to the pressure that corresponds with simulation s...

A model for soliton dynamics on a hydrogen-bond network in helical proteins is proposed. It employs in three dimensions the formalism of fully integrable Toda lattices which admits phonons as well as solitons along the hydrogen-bonds of the helices. A simulation of the three dimensional Toda lattice system shows that the solitons are spontaneously created and are stable and moving along the hel...

We discuss the possibility of implementing asynchronous replica-exchange (or parallel tempering) molecular dynamics. In our scheme, the exchange attempts are driven by asynchronous messages sent by one of the computing nodes, so that different replicas are allowed to perform a different number of time-steps between subsequent attempts. The implementation is simple and based on the message-passi...

We study the Brownian dynamics of flexible and semiflexible polymer chains densely grafted on a flat substrate, upon rapid quenching of the system when the quality of solvent becomes poor and chains attempt collapse into a globular state. The collapse process of such a polymer brush differs from individual chains, both in its kinetics and its structural morphology. We find that the resulting co...