Precipitative mixing experiments have been conducted with the aid of a turbidimeter and a darkfield microscope. The results of these experiments, correlated with observations of macroscopic features, indicate that serological precipitation is largely governed by a highly specific mechanism except in the terminal period, when the operation of non-specific forces becomes apparent. The findings ar...

In theoretical physics, paradoxes are good. That’s paradoxical, since a paradox appears to be a contradiction, and contradictions imply serious error. But Nature cannot realize contradictions. When our physical theories lead to paradox we must find a way out. Paradoxes focus our attention, and we think harder. When David Gross and I began the work that led to this Nobel Prize [1, 2, 3, 4], in 1...

Internal friction and void ratio will change among granular particles under vibration, and the size of void ratio directly affects strength of granular media. To further study the effect of vibration parameters on granular mechanical properties, discrete element method is used to simulate particles motion in a vibrating rectangular case by PFC2D software and study the influence of vibration fre...

We use numerical simulations to understand how random deviations from the ideal spherical shape affect the ability of hard particles to form fcc crystalline structures. Using a system of hard spheres as a reference, we determine the fluid-solid coexistence pressures of both shape-polydisperse and monodisperse systems of aspherical hard particles. We find that when particles are sufficiently iso...

Polystyrene particles of different sizes are optically trapped with a gaussian beam from a He-Cd laser operating at 442 nm. The particles are observed to exhibit luminescence after a certain trapping time followed by an escape from the optical trap. The observed luminescence is explained in terms of the photodegradation of the polystyrene backbone. It is speculated that these chemical modificat...

Particles moving on crystalline surfaces and driven by external forces or flow fields can acquire velocities along directions that deviate from that of the external force. This effect depends upon the characteristics of the particles, most notably particle size or particle index of refraction, and can therefore be (and has been) used to sort different particles. We introduce a simple model for ...

Sorting of colloidal particles of different sizes is of importance in the transport and delivery of such particles in biological, materials science, and other technological contexts. A successful methodology involves the flow of a mixture of particles over designer surfaces presenting a periodic array of traps (optical tweezers) or microfabricated obstacles. The trajectories of the particles ov...

The computer simulation study of Portland cement blending confirmed the major mechanism to be size segregation in the Interfacial Transition Zones around the aggregate particles. Fine particles tend to move through the skeleton of larger particles towards the surface of the aggregate grains, improving local density. But the most interesting feature is a disproportionately larger internal bond c...

It is shown that a microscopic system consisting of Brownian particles moving in a spatially asymmetric but periodic potential (ratchet) and contacting with the alternating hot and cold reservoirs along space coordinate and an external force applying on the particles may work as a refrigerator. In order to clarify the underlying physical pictures of the system, the heat flows via both the poten...

Monodisperse microgel latex with homogeneous cross-link density distribution within the particles was prepared by feeding the monomer and cross-linker into the reaction mixture in a regulated way during the polymerization. To determine the appropriate monomer feeding parameters, the kinetics of the particle formation was investigated by HPLC. The swelling and optical characteristics of the prep...