ANALYSIS OF DESIGN FEATURES OF FLEXIBLE PAVEMENTS ON FEDERAL HIGHWAYS IN RUSSIA

Abstract. Nowadays the pavements of highways in Russia work under difficult conditions of constantly growing traffic volume. The current method for flexible pavements design has a number of serious disadvantages. It does not take into complete account the best practices in design and the actual operating conditions for highways. In a number of cases, this leads to the design of inefficient structures of pavements with a short service life.On a number of federal roads, there are observed rutting and premature wear out of road surface in the first years of the operation. Drainage sand layers and shallow drainage drains are quickly working out. Geosynthetic materials are sometimes used unreasonably. The design life of pavements does not comply with the current standards. In Russia the effective road construction materials are not yet completely used up, as well as local materials reinforced with astringents. The actual experience in operating various road structures with the identification of the most optimal solutions is still poorly considered, except for certain regions.Thus, an urgent need has arisen to develop standard designs of pavements for various natural and climatic conditions in Russia ensuring pavements' efficient operation. It is necessary to analyze the existing pavement designs on the federal highways under various road building climatic zones to develop the standard pavement designs.Keywords: flexible pavements, typical constructions of pavements

Two-dimensional superintegrable metrics with one linear and one cubic integral

We describe all local Riemannian metrics on surfaces whose geodesic flows are superintegrable with one integral linear in momenta and one integral cubic in momenta. We also show that some of these metrics can be extended to the 2-sphere. This gives us new examples of Hamiltonian systems on the sphere with integrals of degree three in momenta, and the first examples of superintegrable metrics of nonconstant curvature on a closed surfaceComment: 35 page

Delayed Onset of Positive Feedback Activation of Rab5 by Rabex-5 and Rabaptin-5 in Endocytosis

BACKGROUND: Rabex-5 is a guanine nucleotide exchange factor (GEF) that specifically activates Rab5, i.e., converting Rab5-GDP to Rab5-GTP, through two distinct pathways to promote endosome fusion and endocytosis. The direct pathway involves a pool of membrane-associated Rabex-5 that targets to the membrane via an early endosomal targeting (EET) domain. The indirect pathway, on the other hand, involves a cytosolic pool of Rabex-5/Rabaptin-5 complex. The complex is recruited to the membrane via Rabaptin-5 binding to Rab5-GTP, suggesting a positive feedback mechanism. The relationship of these two pathways for Rab5 activation in the cell is unclear. METHODOLOGY/PRINCIPAL FINDINGS: We dissect the relative contribution of each pathway to Rab5 activation via mathematical modeling and kinetic analysis in the cell. These studies show that the indirect pathway constitutes a positive feedback loop for converting Rab5-GDP to Rab5-GTP on the endosomal membrane and allows sensitive regulation of endosome fusion activity by the levels of Rab5 and Rabex-5 in the cell. The onset of this positive feedback effect, however, contains a threshold, which requires above endogenous levels of Rab5 or Rabex-5 in the cell. We term this novel phenomenon "delayed response". The presence of the direct pathway reduces the delay by increasing the basal level of Rab5-GTP, thus facilitates the function of the Rabex-5/Rabaptin-5-mediated positive feedback loop. CONCLUSION: Our data support the mathematical model. With the model's guidance, the data reveal the affinity of Rabex-5/Rabaptin-5/Rab5-GTP interaction in the cell, which is quantitatively related to the Rabex-5 concentration for the onset of the indirect positive feedback pathway. The presence of the direct pathway and increased Rab5 concentration can reduce the Rabex-5 concentration required for the onset of the positive feedback loop. Thus the direct and indirect pathways cooperate in the regulation of early endosome fusion

Computational study of electrostatic contribution to membrane dynamics

Electrostatics plays a crucial role in the membrane biology. Negatively charged lipids (such as PS, PA and PIP2) are subject to redistribution under the action of electrostatic forces during various signalling events. Membrane recruitment of multiple signalling proteins (such as MARCKS or Src kinase) is often maintained by positively charged polybasic domains (PD). Even though adsorption of these proteins to the cellular membrane has been extensively investigated, very little is known about how electrostatic interactions contribute to their membrane lateral dynamics. This thesis presents an investigation of the contribution of electrostatic interactions to the membrane lateral dynamics by means of novel computational tools. First, I developed a dynamic Monte-Carlo automaton that faithfully simulates lateral diffusion of the adsorbed positively charged PD of a peripheral membrane protein, as well as the dynamics of mono- (PS, PA) and polyvalent (PIP2) anionic lipids within the bilayer. This model allowed to investigate the major characteristics of protein-membrane diffusion on the uniform membrane. In agreement with earlier results, the simulations revealed the following microscopic phenomena: 1) Electrostatic lipid demixing in the vicinity of the PD; 2) PD interacts with PIP2 stronger than with monovalent lipids. On the spatially heterogeneous membrane the automaton predicted a directional drift of the PD, which was validated by a simple mean-field analytical model. The predicted phenomenon could potentially play a major role in membrane domain formation. To test this hypothesis and to investigate the membrane dynamics on larger scales I developed a continuous model, which was based on the results of the automaton simulations. The results of the continuous model and the Monte-Carlo simulations were shown to be in quantitative agreement. The continuous model allows one to simulate the electrostatic membrane dynamics on micrometer scales and can be used to describe various biologically important processes, such as endocytic cup initiation.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Study of Lawn Vegetation under the Influence of Mining and Processing Enterprise Activity in the Climatic Conditions of the Arctic Zone

The purpose of this study was to examine the vegetation dynamics of various lawn grass species in the city of Apatity, Murmansk region, when exposed to anthropogenic and atmospheric pollution impacts. The dust concentration in the atmospheric air was recorded, its mineralogical analysis was carried out, and the dynamics of the development of various lawn types under the anthropogenic load was studied. Cases of exceeding the MPC of dust particles in the atmospheric air were recorded. Nepheline grains were found in the dust samples, which is indicative of pollution migration from the nearby tailings storage facility. It was shown that lawns are able to grow intensively in severe climatic conditions and under the influence of mining and processing enterprises

Usuwanie jonów fluorkowych z wody kopalnianej

Murmansk Region is home to some major mining and mineral sites. One of the most challenging environmental problems in the mining industry is mine water treatment. For example, the rocks of the deposit operated by Lovozero Mining and Mineral Processing Company contain villiomite (NaF). It is highly soluble in water, and the mine waters at the site have a high content of fluoride ions – significantly above the maximum permissible values. Lab-scale experiments were conducted to test various reagents and different initial concentrations of fluoride ions in the treatment of model solutions and mine water. Depending on the initial concentrations, magnesium and calcium-containing sorbents are proposed for the defluorization of water. Using scanning electron microscopy and microprobe analysis, it was found that fluorine can be bound in poorly soluble compounds, such as, for example, fluorite. Pilot trials are planned.Region Murmański jest regionem silnie uprzemysłowionym, jest lokalizacją wielu kopalń. Jednym z najtrudniejszych problemów środowiskowych w górnictwie jest uzdatnianie wód kopalnianych. Przedstawiono przykład kopalni Lovozero Mining and Mineral Processing. Złoże zawiera villiaumit (NaF). Jest to minerał dobrze rozpuszczalny w wodzie. Wody kopalniane w tym miejscu mają wysoką zawartość jonów fluorkowych - znacznie powyżej maksymalnych dopuszczalnych wartości. Przeprowadzono eksperymenty na skalę laboratoryjną w celu przetestowania różnych odczynników i różnych początkowych stężeń jonów fluorkowych w obróbce roztworów modelowych i wody kopalnianej. W zależności od początkowych stężeń do odfluoryzacji wody proponuje się sorbenty zawierające magnez i wapń. Za pomocą skaningowej mikroskopii elektronowej i analizy mikropróbek stwierdzono, że fluor może wiązać się w słabo rozpuszczalnych związkach, takich jak na przykład fluoryt. Planowane są próby pilotażowe

Study of the effect of passivation layers on capacitance of AlGaN/GaN heterostructures

MOCVD grown AlGaN/GaN heterostructures on sapphire and silicon substrates have been studied. The capacity–voltage characteristic have been measured in the 200 Hz–1 MHz frequency range with a planar position of mercury and second probe on the specimen surface. The shape of the typical C–V curves for the heterostructures with upper undoped i-AlGaN and i-GaN layers 1,5–2,5 nm in thickness have been analyzed. The appearance of a typical peak on the C–V curves upon a change from the depletion region to the accumulation region has been registered in some structures with an i-GaN layer thickness of 5 nm and more at low frequencies (f<50–200 kHz). The height of this peak increased with a reduction of frequency. It has been found experimentally that the frequency at which the peak is registered can depend on the dislocation density in heterostructures. Possible explanation of the peak formation and band diagram transformation in these structures under an applied electric field have been presented. We show that the application of a Si3N4 passivation layer results in the formation of additional positive charge

Lateral Dynamics of Proteins with Polybasic Domain on Anionic Membranes: A Dynamic Monte-Carlo Study

Positively charged polybasic domains are essential for recruiting multiple signaling proteins, such as Ras GTPases and Src kinase, to the negatively charged cellular membranes. Much less, however, is known about the influence of electrostatic interactions on the lateral dynamics of these proteins. We developed a dynamic Monte-Carlo automaton that faithfully simulates lateral diffusion of the adsorbed positively charged oligopeptides as well as the dynamics of mono- (phosphatidylserine) and polyvalent (PIP2) anionic lipids within the bilayer. In agreement with earlier results, our simulations reveal lipid demixing that leads to the formation of a lipid shell associated with the peptide. The computed association times and average numbers of bound lipids demonstrate that tetravalent PIP2 interacts with the peptide much more strongly than monovalent lipid. On the spatially homogeneous membrane, the lipid shell affects the behavior of the peptide only by weakly reducing its lateral mobility. However, spatially heterogeneous distributions of monovalent lipids are found to produce peptide drift, the velocity of which is determined by the total charge of the peptide-lipid complex. We hypothesize that this predicted phenomenon may affect the spatial distribution of proteins with polybasic domains in the context of cell-signaling events that alter the local density of monovalent anionic lipids

Severe accident research in the core degradation area: An example of effective international cooperation between the European Union (EU) and the Commonwealth of Independent States (CIS) by the International Science and Technology Center

The paper has two following objectives: - To describe the organization of complex, international, experimental and analytical research of material processes under extreme conditions similar to those of severe accidents in nuclear reactors and, - To inform briefly about some of the results of these studies. The multilateral research program was supported and managed by the International Science and Technology Centre (ISTC). The ISTC was to support non-proliferation of sensitive knowledge and technologies in biological, chemical and nuclear domains by engaging scientists in peaceful research programmes with a broad international cooperation. The main forms of ISTC activity are Research projects and Supporting programs. In the Research projects informal contact expert groups (CEG) were set up by ISTC to improve coordination between adjacent projects and to encourage international collaboration: first of all by the European Commission. The CEG members - experts from the national institutes - evaluated and managed the projects‘ scientific results from initial stage of proposal formulation until the final reporting. They were often involved directly in the project‘s details by joining the Steering Committees of the project. The Contact Expert Group for Severe Accident & Management (CEG-SAM) is one of these groups. Five project groups from this area given as examples from the total of funded 30 projects during 10 years of activity to demonstrate this: 1) QUENCH-VVER from RIAR, Dimitrovgrad & IBRAE, Moscow, and PARAMETER projects (SF1 & SF4) from LUCH, Podolsk & IBRAE, Moscow, concerning a detailed study of bundle quenching from high temperature; 2) Reactor Core Degradation, a modelling project simulating the fuel rod degradation and loss of geometry from IBRAE, Moscow; 3) METCOR projects from NITI, St. Petersburg on the interaction of core melt with reactor vessel steel; 4) CORPHAD & PRECOS projects, NITI St. Petersburg undertook a systematic examination of refractory ceramics relevant to in-vessel and ex-vessel coria, particularly examining poorly characterised, limited data or experimentally difficult systems; and finally, 5) INVECOR project, NNE Kurchatov City, Kazakhstan, This is a large-scale (60 kg) facility to examine the vessel steel retention of corium during the decay heat.JRC.E.2-Hot cell