The Warm Gas in the Milky Way: The Kinematical Model of C iv and Its Connection to Si iv

We compose a 265-sight-line Milky Way C iv line-shape sample using the Hubble Space Telescope/Cosmic Origins Spectrograph archive, which is complementary to the existing Si iv samples. C iv has a higher ionization potential (47–64 eV) than Si iv (33–45 eV), so it also traces warm gas, which is roughly cospatial with Si iv. The spatial density distribution and kinematics of C iv are identical to those Si iv within ≈2σ. C iv is more sensitive to the warm gas density distribution at large radii with a higher element abundance. Applying the kinematical model to the C iv sample, we find two possible solutions of the density distribution, which are distinguished by the relative extension along the disk midplane and the normal-line direction. Both solutions can reproduce the existing sample and suggest a warm gas disk mass of log M ( M ⊙ ) ≈ 8 and an upper limit of log M ( M ⊙ ) < 9.3 within 250 kpc, which is consistent with Si iv. There is a decrease in the C iv/Si iv column density ratio from the Galactic center to the outskirts by 0.2–0.3 dex, which may suggest a phase transition or different ionization mechanisms for C iv and Si iv. Also, we find that the difference between C iv and Si iv is an excellent tracer of small-scale features, and we find a typical size of 5°–10° for possible turbulence within individual clouds (≈1 kpc).

Properties of Journal Bearing Materials That Determine Their Wear Resistance on the Example of Aluminum-Based Alloys

Potential relations of tribological characteristics of aluminum antifriction alloys with their compositions and mechanical properties were investigated. In this regard, the properties of eight aluminum alloys containing tin from 5.4% to 11% doped with lead, copper, silicon, zinc, magnesium, and titanium were studied. Mechanical properties such as hardness, strength, relative extension, and impact strength were analyzed. Within the tribological tests seizure load and wear of material were evaluated and secondary structures were studied afterwards. The absence of a definitive correlation between tribological behavior and mechanical properties was shown. It was determined that doping tin over 6% is excessive. The seizure load of the alloys increases with the magnesium content. Secondary structures of the alloys with higher wear rates contain one order less magnesium and tin.

RESEARCH FOR FORMING POROUS STRUCTURES BASED ON PVC

In this work, we report on phase equilibrium in systems «plasticizer mix - blowing agent». Dioctiphthalate, butylbenzylphthalate and dicresyl phosphate were used as plasticizer, and simple oligoesters (ethylene glycol, diethylene glycol, triethylene glycol) served as a blowing agent. We conducted an experiment and built triple phase diagrams. Diphenylcresylphosphate proved to be fully compatible with diethylene and triethylene glycol, but not to the ethylene one. Triple systems «Butyl benzyl phthalate - Diphenylcresylphosphate - Simple oligoesters» turned out to be homogeneous for several created compounds. To achieve this for a triple system, the minimal quantity threshold is either 20% of triethylene glycol or 30% of diethylene. As for the case of dioctyl phthalate for second plasticizer, the minimal threshold for blowing agents is 70%. We constructed a device that allows to detect phase equilibrium for liquid systems. We devised several compounds and a technological proccess for creating porous PVC-based membranes using thermal molding. We selected such molding due to several advantages when compared to other methods for producing porous membranes, such as: required density, elasticity, open pores, and narrow pore size distribution. We managed to create several samples based on emulsion type PVC, butyl benzyl phthalate, diphenylcresyl phosphate, diethylene and triethylene glycol. During the phase inversion thermal process temperature should be around 180 degrees of celsium. Porous materials have the following properties: open porosity 38-44%, breaking strength 1.0 – 1.2 MРa, relative extension 43-63%, maximal pore size (2.3 – 2.8)·10-6 m, average pore size (0.5 – 1.1)·10-6 m.

Modification of Рolymer Wastes and Obtaining Com Comрosites Based on Them Annotation

The sources of scientific literature on the research have been investigated, various approaches to the processing and modification of polymers have been analyzed and the main direction of the study have been identified. The changes in the properties of thin layers of industrially produced low-density polyethylene (LDPE) grades 10803-20 and 16603-011 operating under different climatic conditions have been studied. It has been determined that changes with different intensities occur in the structure and in this connection in the physical and mechanical properties of LDPE that was in operation at different time intervals and in different climatic conditions of the Absheron Peninsula and the Aran region: melt flow index of polymer alloy, tensile strength at break, relative extension and values of other indicators are deteriorating. In polymer samples is formed 24,2 – 28,6% of insoluble phase and as a result of oxidation up to  12,3 – 16,8% carbonyl, hydroxyl and other functional groups.

Relative Extension of Continuous Mappings

In this paper, the notion of a relative extension of continuous mappings is defined. The relative extension of continuous mappings is the generalization of the notion of a relative retract in topological spaces. The relative extension of continuous mappings will be applied to fixed point theory.

Polylactide-Based Stent Coatings: Biodegradable Polymeric Coatings Capable of Maintaining Sustained Release of the Thrombolytic Enzyme Prourokinase

The novelty of the study is the development, creation, and investigation of biodegradable polymeric membranes based on polylactide, that are capable of directed release of large molecular weight biomolecules, particularly, prourokinase protein (MW = 46 kDa). Prourokinase is a medication with significant thrombolytic activity. The created membranes possess the required mechanical properties (relative extension value from 2% to 10%, tensile strength from 40 to 85 MPa). The membranes are biodegradable, but in the absence of living cells in a water solution they decompose by less than 10% in half a year. The created membranes are capable of controlled prourokinase release into intercellular space, and the total enzymatic activity of prourokinase does not decrease by more than 12%. The daily release of prourokinase from one square centimeter of the membrane ranges from 1 to 40 μg per day depending on the technique of membrane preparation. The membranes have no acute toxic effect on cells accreting these surfaces de novo. The number of viable cells is at least 96%−97% of the overall cell count. The mitotic index of the cells growing on the surface of the polymeric films comprised around 1.5%. Histological examination did not reveal any disorders in tissues of the animals after the implantation of polymer membranes based on polylactide, both alone and as components of stent cover. Implantation of stents covered with prourokinase-containing polymers led to the formation of a mature connective tissue capsule that is thicker than in the case of uncovered stents. Thus, various polylactide-based biodegradable polymeric membranes possessing the required mechanical properties and capable of prolonged and directed release of prourokinase macromolecules are developed and investigated in the study.

Properties of Hemp Fibres Reinforced PLA Composites

In this study 3 samples of bio-composite materials with different proportion of hemp fibers in the PLA matrix were developed, their comparative analysis and certain mechanical properties were investigated. Bio-composite hemp and polylactide (PLA) fibers were evenly blended using carding technology. The obtained blanks were treated for thermosetting at a fixed temperature of 180°C and a pressure of 100 kN, as well as controlled heating, compression and cooling time were applied. The mechanical properties (tensile strength σt, elastic modulus Et, relative extension ɛt) of composite material were determined.

Oblique rifting: the rule, not the exception

Movements of tectonic plates often induce oblique deformation at divergent plate boundaries. This is in striking contrast with traditional conceptual models of rifting and rifted margin formation, which often assume 2-D deformation where the rift velocity is oriented perpendicular to the plate boundary. Here we quantify the validity of this assumption by analysing the kinematics of major continent-scale rift systems in a global plate tectonic reconstruction from the onset of Pangea breakup until the present day. We evaluate rift obliquity by joint examination of relative extension velocity and local rift trend using the script-based plate reconstruction software pyGPlates. Our results show that the global mean rift obliquity since 230 Ma amounts to 34° with a standard deviation of 24°, using the convention that the angle of obliquity is spanned by extension direction and rift trend normal. We find that more than ∼ 70 % of all rift segments exceeded an obliquity of 20° demonstrating that oblique rifting should be considered the rule, not the exception. In many cases, rift obliquity and extension velocity increase during rift evolution (e.g. Australia-Antarctica, Gulf of California, South Atlantic, India-Antarctica), which suggests an underlying geodynamic correlation via obliquity-dependent rift strength. Oblique rifting produces 3-D stress and strain fields that cannot be accounted for in simplified 2-D plane strain analysis. We therefore highlight the importance of 3-D approaches in modelling, surveying, and interpretation of most rift segments on Earth where oblique rifting is the dominant mode of deformation.

Boundary Bound Diffraction: A Combined Spectral and Bohmian Analysis

The diffraction-like process displayed by a spatially localized matter wave is here analyzed in a case where the free evolution is frustrated by the presence of hard-wall-type boundaries (beyond the initial localization region). The phenomenon is investigated in the context of a nonrelativistic, spinless particle with mass m confined in a one-dimensional box, combining the spectral decomposition of the initially localized wave function (treated as a coherent superposition of energy eigenfunctions) with a dynamical analysis based on the hydrodynamic or Bohmian formulation of quantum mechanics. Actually, such a decomposition has been used to devise a simple and efficient analytical algorithm that simplifies the computation of velocity fields (flows) and trajectories. As it is shown, the development of space-time patters inside the cavity depends on three key elements: the shape of the initial wave function, the mass of the particle considered, and the relative extension of the initial state with respect to the total length spanned by the cavity. From the spectral decomposition it is possible to identify how each one of these elements contribute to the localized matter wave and its evolution; the Bohmian analysis, on the other hand, reveals aspects connected to the diffraction dynamics and the subsequent appearance of interference traits, particularly recurrences and full revivals of the initial state, which constitute the source of the characteristic symmetries displayed by these patterns. It is also found that, because of the presence of confining boundaries, even in cases of increasingly large box lengths, no Fraunhofer-like diffraction features can be observed, as happens when the same wave evolves in free space. Although the analysis here is applied to matter waves, its methodology and conclusions are also applicable to confined modes of electromagnetic radiation (e.g., light propagating through optical fibers).

Oblique rifting: the rule, not the exception

Movements of tectonic plates often induce oblique deformation at divergent plate boundaries. This is in striking contrast with traditional conceptual models of rifting and rifted margin formation, which often assume 2D deformation where the rift velocity is oriented perpendicular to the plate boundary. Here we quantify the validity of this assumption by analysing the kinematics of major continent-scale rift systems in a global plate tectonic reconstruction from the onset of Pangea breakup until present-day. We evaluate rift obliquity by joint examination of relative extension velocity and local rift trend using the script-based plate reconstruction software pyGPlates. Our results show that the global mean rift obliquity amounts to 34° with a standard deviation of 24°, using the convention that the angle of obliquity is spanned by extension direction and rift trend normal. We find that more than ~ 70 % of all rift segments exceeded an obliquity of 20° demonstrating that oblique rifting should be considered the rule, not the exception. In many cases, rift obliquity and extension velocity increase during rift evolution (e.g. Australia-Antarctica, Gulf of California, South Atlantic, India-Antarctica), which suggests an underlying geodynamic correlation via obliquity-dependent rift strength. Oblique rifting produces 3D stress and strain fields that cannot be accounted for in simplified 2D plane strain analysis. We therefore highlight the importance of 3D approaches in modelling, surveying, and interpretation of most rift segments on Earth where oblique rifting is the dominant mode of deformation.