Alignments of a Microparticle Pair in a Glow Discharge

Stability of a vertically aligned microparticle pair in a stratified glow DC discharge is experimentally investigated. Using laser perturbations, it is shown that, for the same discharge parameters, a pair of microparticles can be suspended in two stable configurations: vertical and horizontal. The interparticle interaction and the electric field of the stratum in the region of particle levitation are quantitatively investigated for the first time. The decharging effect of the lower (downstream) particle by the ion flow wake is also observed for the first time in a glow discharge. The obtained experimental data made it possible to check the analytical criteria for the configurational stability of the system.

Thermodynamic Modeling of Multicomponent Rare Earth Nitrates Aqueous Systems

Solubility constants of rare earth (RE) nitrates crystalline hydrates are determined in a wide temperature range (−30 to 120°C), salts solubilities and phase diagrams of water–RE nitrate systems are calculated. For multicomponent (n > 5) solutions of RE nitrates the assessment of solution properties as well as phase diagrams are shown to be feasible within experimental uncertainty. In case of mixtures of RE nitrates with similar hydrodynamic radii of ions, the parameters of RE1–RE2 interparticle interaction can be ignored without losing accuracy of thermodynamic modeling.

Enhanced Magnetization in a Frustrated Spin System by Ni+ Ion Beam Irradiation

We investigate the magnetic properties in a frustrated spin system of carbonyl iron (CI) particles before and after Ni+ ion beam irradiation. Upon increasing temperatures, the saturation magnetization exhibits an anomalous increase, which is more intense after the beam irradiation. The zero-field cooled (ZFC) magnetization data show an anomalous increase up to 300 K, regardless of the beam irradiation. After the irradiation, unlike in the unirradiated CI particles, the ZFC curve shows separated regimes, reflecting two distributions of the blocking temperature, which may be related to the particle distribution summed with two distribution functions. After the irradiation, strong interparticle interaction may be present due to the effect of dipolar interaction among CI particles doped Ni ions, leading to the enhanced magnetization. We may suggest that the anomalous magnetization behavior can be ascribed to frustration in the internal magnetic order for the unirradiated CI particles, and further interparticle interaction for the irradiated CI particles.

Formation of Kinetics Coherent Structures in Weakly Collisional Media

The formation of nonlinear, nonstationary structures in weakly collisional media with collective interactions are investigated analytically within the framework of the kinetic description. This issue is considered in one-dimensional geometry using collision integral in the Bhatnagar-Gross-Krook form and some model forms of the interparticle interaction potentials that ensure the finiteness of the energy and momentum of the systems under consideration. As such potentials, we select the Yukawa potential, the δ-potential, which describes coherent structures in a plasma. For such potentials we obtained a dispersion relation which makes it possible to estimate the size and type of the forming structures.

Comparison of Huggins Coefficients and Osmotic Second Virial Coefficients of Buffered Solutions of Monoclonal Antibodies

The Huggins coefficient kH is a well-known metric for quantifying the increase in solution viscosity arising from intermolecular interactions in relatively dilute macromolecular solutions, and there has been much interest in this solution property in connection with developing improved antibody therapeutics. While numerous kH measurements have been reported for select monoclonal antibodies (mAbs) solutions, there has been limited study of kH in terms of the fundamental molecular interactions that determine this property. In this paper, we compare measurements of the osmotic second virial coefficient B22, a common metric of intermolecular and interparticle interaction strength, to measurements of kH for model antibody solutions. This comparison is motivated by the seminal work of Russel for hard sphere particles having a short-range “sticky” interparticle interaction, and we also compare our data with known results for uncharged flexible polymers having variable excluded volume interactions because proteins are polypeptide chains. Our observations indicate that neither the adhesive hard sphere model, a common colloidal model of globular proteins, nor the familiar uncharged flexible polymer model, an excellent model of intrinsically disordered proteins, describes the dependence of kH of these antibodies on B22. Clearly, an improved understanding of protein and ion solvation by water as well as dipole–dipole and charge–dipole effects is required to understand the significance of kH from the standpoint of fundamental protein–protein interactions. Despite shortcomings in our theoretical understanding of kH for antibody solutions, this quantity provides a useful practical measure of the strength of interprotein interactions at elevated protein concentrations that is of direct significance for the development of antibody formulations that minimize the solution viscosity.

Thermodiffusion anisotropy under magnetic field in ionic liquid-based ferrofluids

Ferrofluids based on maghemite nanoparticles (NPs), typically 10 nm in diameter, are dispersed in an ionic liquid (1-ethyl 3-methylimidazolium bistriflimide - EMIM-TFSI). The average interparticle interaction is found repulsive by...

RELATIVE PRINCIPLE OF FULL ABSORPTION

The paper discusses the principle of complete absorption, which plays the same role in relational theory as the principle of equivalence in general relativity and the principle of waveparticle duality in quantum theory. The physical essence of this principle boils down to the fact that a sufficiently large number of particles must be present in the Universe so that complete absorption of radiation from any source is possible. This implies complete equivalence, from the experimental point of view, of direct interparticle interaction and the interaction carried by a local field in spacetime. It is noted that in its classical interpretation the Fokker variational principle, on which the theory of direct interparticle interaction is based, contains a dilemma caused by two mutually contradictory necessary properties of the interaction action. One of the options for overcoming this dilemma is proposed.