Channel processes and its management on navigable rivers

Inland waterways are the sector of the economy that is most dependent on channel processes and their management to ensure safety and favourable conditions for navigation. The main goals of the river channel management are to improve the waterways in terms of navigation and, at the same time, to preserve the rivers as natural sites. The presented study defines the criteria for classification of rivers and river sections according to the complexity of channel processes, their forecasting and management. The classification of rivers as waterways has been provided based on the complexity of channel process management and designing of dredging works and investments aimed at improving the navigation conditions. Examples of this approach are given based on specific rivers of Russia

Short-term dynamics of river water turbidity

An overview of the recently collected datasets of highly discrete water turbidity measurements has allowed for the first hydrological and geographical analysis of short-term fluctuations in water turbidity and the composition of suspended sediments. The novel methodology has been developed to estimate a value of TI, which is the ratio of the difference between the maximum and minimum turbidity for a short period of time (ΔTi) (1 hour with the measurement frequency of 20 minutes) and the total turbidity difference for the water regime phase under study (ΔT HE ). Higher TI values correspond to a greater contribution of diurnal (20-minute) turbidity fluctuations to the seasonal variability of sediment yield. Rivers have been grouped according to the value of water turbidity fluctuations within one hour (20-minute): glacier-fed rivers (the Tarfala, the Dzhankuat) (TI amounts to 0.17-0.22); volcanic rivers (0.22–0.25) and lowland rivers (the Selenga, the Western Dvina) (0.09

Modeling of the heliospheric interface: multi-component nature of the heliospheric plasma

We present a new model of the heliospheric interface - the region of the solar wind interaction with the local interstellar medium. This new model performs a multi-component treatment of charged particles in the heliosphere. All charged particles are divided into several co-moving types. The coldest type, with parameters typical of original solar wind protons, is considered in the framework of fluid approximation. The hot pickup proton components created from interstellar H atoms and heliospheric ENAs by charge exchange, electron impact ionization and photoionization are treated kinetically. The charged components are considered self-consistently with interstellar H atoms, which are described kinetically as well. To solve the kinetic equation for H atoms we use the Monte Carlo method with splitting of trajectories, which allows us 1) to reduce statistical uncertainties allowing correct interpretation of observational data, 2) to separate all H atoms in the heliosphere into several populations depending on the place of their birth and on the type of parent protons.Comment: A&A accepte

Scatter-free pickup ions beyond the heliopause as a model for the Interstellar Boundary Explorer (IBEX) ribbon

We present new kinetic-gasdynamic model of the solar wind interaction with the local interstellar medium. The model incorporates several processes suggested by McComas et al. (2009) for the origin of the heliospheric ENA ribbon -- the most prominent feature seen in the all sky maps of heliospheric ENAs discovered by the Interstellar Boundary Explorer (IBEX). The ribbon is a region of enhanced fluxes of ENAs crossing almost the entire sky. Soon after the ribbon's discovery it was realized (McComas et al., 2009) that the enhancement of the fluxes could be in the directions where the radial component of the interstellar magnetic field around the heliopause is close to zero (Schwadron et al., 2009). Our model includes secondary charge exchange of the interstellar H atoms with the interstellar pickup protons outside the heliopause and is a further advancement of the kinetic-gasdynamic model by Malama et al. (2006) where pickup protons were treated as a separate kinetic component. Izmodenov et al. (2009) have shown in the frame of Malama's model that the interstellar pickup protons outside the heliopause maybe a significant source of ENAs at energies above 1 keV. The difference between the current work and that of Izmodenov et al. (2009) is in the assumption of no-scattering for newly created pickup protons outside the heliopause. In this limit the model produces a feature qualitatively similar to the ribbon observed by IBEX.Comment: submitted to ApJ

Fluvial processes as a reflection of river sediment transport. Examples from Russia

Sediment transport is one of the main elements of fluvial processes; and with it fluvial processes themselves are elements of sediment supply into rivers. The amount of sediment transported by a stream is determined by its carrying capacity, which changes in line with spatial and temporal changes in stream hydraulic characteristics. Correlations between them set the conditions for vertical channel deformation. When a riverbed is composed of heavy material, stream carrying capacity is realized due to horizontal channel deformations. The complexity of correlations between fluvial processes and sediment transport is determined by the transport of the latter in suspended and bed load forms, permanent conversions from one form to another in line with changes in stream hydraulic characteristics along and across the river channel, from the high-water to the low-water period versus the water flow in river branches. Sediment load itself and its magnitude determine the development of channel relief forms and the transformation of straight channels to meandering or braided channels. The main role in channel development is played by bed load flow. The ratio of bed load to suspended load determines changes in morphometric channel characteristics and its stability as well as effects the development of channel meanders and river bifurcations. At the same time, it is important to take into account the proportion of suspended and bed load components and their proportion in channel-forming sediment

Heating of the solar wind in the outer heliosphere

International audienceSmall-scale Alfvènic turbulence in the outer heliosphere is mainly determined by a source which is connected with the instability of the initially highly anisotropic velocity distribution of interstellar pick-up protons. The main portion of the generated turbulent energy is subsequently absorbed by the pick-up protons themselves due to the cyclotron-resonant interaction between waves and particles. A small fraction of this energy can be transferred to solar wind protons resulting in their heating. The heating is more efficient in the high-speed solar wind

Influence of Adding Ammonium Bifluoride when Leaching Monazite Using Sulphur Acid

The following shows the results of the leaching of monazite concentrate with sulfuric acid in the presence of ammonium bifluoride. It was established that the addition of ammonium bifluoride increases the degree of the leaching monazite concentrate and allows the separation of phosphorous from a mixture of rare earth and radioactive elements

Fluorescence of the Polymethine Dye Tiks and Diagnostics af Cancert

It is shown that the fluorescence of the polymethine dye TIKS, whose absorption and fluorescence bands are located in the spectral region of transmission of biological tissues, can be recorded from a depth of up to 1.5 cm of an animal’s body. The intensity of the fluorescence recorded from the surface of the animal’s body in intravenous injection of the dye (1–2 mg/kg) is in direct proportion to its concentration in tumor nodes and muscles. In rapidly growing tumors, a high (up to 3.6) degree of contrast of the content of the dye is attained in tumor tissues as compared to the surrounding normal tissues. Over the course of 7 days after the injection, the dye is practically completely removed from both the tumor and normal muscular tissues. From the change in the fluorescence intensity in scanning the surface one can determine the regions of localization of tumor nodes against the background of the surrounding normal tissues and the presence of regions with a nonuniform distribution of the dye

A TOOLBOX FOR SEDIMENT BUDGET RESEARCH IN SMALL CATCHMENTS

© 2017, Lomonosov Moscow State University. All rights reserved. Sediment monitoring and assessment remain one of the most challenging tasks in fluvial geomorphology and water quality studies. As a response to various environmental and human disturbance effects, the main sources and pathways of the sediments transported within catchments, especially most pristine small one, may change. The paper discusses state-of-the-art in the sediment budget research for small catchments. We identified nine independent approaches in the sediment transport assessment and applied them in 11 catchments across Eurasia in the framework of an FP-7 Marie Curie-International Research Staff Exchange Scheme in 2012-2016. These methods were classified as: i) Field-based methods (In-situ monitoring of sediment transport;-Soil morphological methods and dating techniques; Sediment source fingerprinting; Sediment-water discharge relationships), ii) GIS and remote sensing approaches (Riverbed monitoring based on remote sensing/historical maps; parametrization of the channel sediment connectivity; Sediment transport remote sensing modeling), and iii) Numerical approaches (Soil erosion modeling and gully erosion (stochastic and empirical models); channel hydrodynamic modeling). We present the background theory and application examples of all selected methods. Linking fieldbased methods and datasets with numerical approaches, process measurements as well as monitoring can provide enhanced insights into sediment transfer and related water quality impacts. Adopting such integrated and multi-scale approaches in a sediment budget framework might contribute to improved understanding of hydrological and geomorphological responses