Electromagnetic field near cosmic string

The retarded Green function of the electromagnetic field in spacetime of a straight thin cosmic string is found. It splits into a geodesic part (corresponding to the propagation along null rays) and to the field scattered on the string. With help of the Green function the electric and magnetic fields of simple sources are constructed. It is shown that these sources are influenced by the cosmic string through a self-interaction with their field. The distant field of static sources is studied and it is found that it has a different multipole structure than in Minkowski spacetime. On the other hand, the string suppresses the electric and magnetic field of distant sources--the field is expelled from regions near the string.Comment: 12 pages, 8 figures (low-resolution figures; for the version with high-resolution figures see http://utf.mff.cuni.cz/~krtous/papers/), v2: two references added, typos correcte

Self-energy and Self-force in the Space-time of a Thick Cosmic String

We calculate the self-energy and self-force for an electrically charged particle at rest in the background of Gott-Hiscock cosmic string space-time. We found the general expression for the self-energy which is expressed in terms of the $S$ matrix of the scattering problem. The self-energy continuously falls down outward from the string's center with maximum at the origin of the string. The self-force is repulsive for an arbitrary position of the particle. It tends to zero in the string's center and also far from the string and it has a maximum value at the string's surface. The plots of the numerical calculations of the self-energy and self-force are shown.Comment: 15 pages, 4 Postscript figures, ReVTe

Experimental: Thermochemical dehydration of oil sludges of different origins

The paper studied the breaking of highly stable oil-water and water-hydrocarbon emulsions of natural and technogenic origin. The main factors are specified which determine the stability and an increased resistance of emulsions to the traditional destruction methods. The effectiveness of thermochemical treatment on various water-oil and water-hydrocarbon emulsions was tested. The demulsifier Rekod-118A was selected as the main reagent used on fields for the destruction of highly stable water-oil emulsions. It was shown that among five provided samples only one sample reduced the content of water to the required standard level after a thermochemical dehydration. It was established that thermochemical dehydration method is generally ineffective for the destruction of highly stable water-oil emulsions and may serve only as the means of preliminary emulsion treatment. It was shown that after thermochemical exposure at 60 °C the water content in IL, HPR, YS emulsions remained at an original level and in MOCW emulsion the water content decreased by 14% and made 19% wt. After the dehydration by thermochemical method, only one sample (LP) out five ones demonstrated the water content reduction to the required standard of performance. Optimum reagent dosage for this raw material made 800 g/t and the process temperature made 60 °C with settling duration of 24 hours

Self-force of a point charge in the space-time of a massive wormhole

We consider the self-potential and the self-force for an electrically charged particle at rest in the massive wormhole space-time. We develop general approach for the renormalization of electromagnetic field of such particle in the static space-times and apply it to the space-time of the wormhole with parameter of the mass, $m$. The self-force is found in manifest form; it is an attractive force. We discus the peculiarities due to massive parameter of the wormhole.Comment: 10 pages, 1 figure text correcte

Classical self-forces in a space with a dispiration

We derive the gravitational and electrostatic self-energies of a particle at rest in the background of a cosmic dispiration (topological defect), finding that the particle may experience potential steps, well potentials or potential barriers depending on the nature of the interaction and also on certain properties of the defect. The results may turn out to be useful in cosmology and condensed matter physics.Comment: 5 pages, 4 figures, revtex4 fil

Vacuum Polarization of Massless Spinor Field in Global Monopole Spacetime

We calculate the renormalized vacuum average of the energy-momentum tensor of massless left-handed spinor field in the pointlike global monopole spacetime using point-separation approach. The general structure of the vacuum average of the energy-momentum tensor is obtained and expressed in terms of $^{ren}$ component, explicit form of which is analyzed in great details for arbitrary solid angle deficit.Comment: 12 pages, REVTEX, print error was correcte

Ground State Energy of Massive Scalar Field in the Background of Finite Thickness Cosmic String

We calculate the ground state energy of a massive scalar field in the background of a cosmic string of finite thickness (Gott-Hiscock metric). Using zeta functional regularization we discuss the renormalization and the relevant heat kernel coefficients in detail. The finite (non local) part of the ground state energy is calculated in 2+1 dimensions in the approximation of a small mass density of the string. By a numerical calculation it is shown to vanish as a function of the radius of the string and of the parameter $\xi$ of the nonconformal coupling.Comment: 23 pages, Latex, 3 figures, subm. to Phys. Rev.

Hybrid Nanoparticles for Haloperidol Encapsulation: Quid Est Optimum?

The choice of drug delivery carrier is of paramount importance for the fate of a drug in a human body. In this study, we have prepared the hybrid nanoparticles composed of FDA-approved Eudragit L100-55 copolymer and polymeric surfactant Brij98 to load haloperidol-an antipsychotic hydrophobic drug used to treat schizophrenia and many other disorders. This platform shows good drug-loading efficiency and stability in comparison to the widely applied platforms of mesoporous silica (MSN) and a metal-organic framework (MOF). ZIF8, a biocompatible MOF, failed to encapsulate haloperidol, whereas MSN only showed limited encapsulation ability. Isothermal titration calorimetry showed that haloperidol has low binding with the surface of ZIF8 and MSN in comparison to Eudragit L100-55/Brij98, thus elucidating the striking difference in haloperidol loading. With further optimization, the haloperidol loading efficiency could reach up to 40% in the hybrid Eudragit L100-55/Brij98 nanoparticles with high stability over several months. Differential scanning calorimetry studies indicate that the encapsulated haloperidol stays in an amorphous state inside the Eudragit L100-55/Brij98 nanoparticles. Using a catalepsy and open field animal tests, we proved the prolongation of haloperidol release in vivo, resulting in later onset of action compared to the free drug

Thermomechanical Dehydration of Highly-Stable Dispersions of Liquid Pyrolysis Products

© 2018, Springer Science+Business Media, LLC, part of Springer Nature. Highly organized and highly stable water—hydrocarbon dispersions of liquid pyrolysis products and an ethane fraction were studied. Water evaporation was used as a dehydration method. Mixtures containing a water cut (20-75 mass%) were studied. Feedstock was separated by a thermomechanical method into bottom-product and distillate fractions. The dehydration efficiency was assessed based on the water cut in the bottom products. The water content in all studied mixtures was reduced to trace levels in the bottom products. Increasing the water cut in the emulsions was shown to increase the ratio of recovered hydrocarbon distillate to bottom products whereas diluting the starting emulsion with light pyrolysis resin had the opposite effect on the yield of dehydration products depending on the starting pyrolysis feedstock

Thermomechanical Dehydration of Highly-Stable Dispersions of Liquid Pyrolysis Products

© 2018, Springer Science+Business Media, LLC, part of Springer Nature. Highly organized and highly stable water—hydrocarbon dispersions of liquid pyrolysis products and an ethane fraction were studied. Water evaporation was used as a dehydration method. Mixtures containing a water cut (20-75 mass%) were studied. Feedstock was separated by a thermomechanical method into bottom-product and distillate fractions. The dehydration efficiency was assessed based on the water cut in the bottom products. The water content in all studied mixtures was reduced to trace levels in the bottom products. Increasing the water cut in the emulsions was shown to increase the ratio of recovered hydrocarbon distillate to bottom products whereas diluting the starting emulsion with light pyrolysis resin had the opposite effect on the yield of dehydration products depending on the starting pyrolysis feedstock