Evidence for microplastics contamination of the remote tributary of the Yenisei River, Siberia - The pilot study results

This study is a pioneering attempt to count microplastics (MPs) in the Yenisei River system to clarify the role of Siberian Rivers in the transport of MPs to the Arctic Ocean. The average MPs content in the surface water of the Yenisei large tributary, the Nizhnyaya Tunguska River, varied from 1.20 ± 0.70 to 4.53 ± 2.04 items/m3, tending to increase along the watercourse (p < 0.05). Concentrations of MPs in bottom sediments of the two rivers were 235 ± 83.0 to 543 ± 94.1 with no tendency of downstream increasing. Linear association (r = 0.952) between average organic matter content and average counts of MPs in bottom sediments occurred. Presumably MPs originated from the daily activities of the in-situ population. Further spatial-temporal studies are needed to estimate the riverine MPs fluxes into the Eurasian Arctic seas

Mathematical modeling of thermal effectiveness of a ternary combined cycle plant

The urgency of this work is determined by the intensification of the role of steam-gas technologies (combined cycle technologies) in the field of power engineering in Russia and throughout the world. Developed mathematical model of ternary combined cycle plants, which is based on balance method includes system of mass balance and energy balance equations for ternary combined cycle plants and its units, equations of steam expansion in turbine and working fluids thermodynamic properties. On the basis of a model was carried out the analysis of the impact of the structure and thermodynamic parameters on thermal effectiveness of heat-recovery ternary combined cycle plants which cycle is the combination of three working substance cycles, one of which is low-boiling substance. The analysis of the thermal effectiveness of ternary combined cycle plants was made by means of the small-deflection method. The optimal parameters of operating environment and structure of a ternary combined cycle plants were determined

Preliminary screening for microplastic concentrations in the surface water of the Ob and Tom Rivers in Siberia, Russia

This study characterizes the abundance and morphology of microplastics in surface water of the Ob River and its large tributary, the Tom River, in western Siberia. The average number of particles for two rivers ranged from 44.2 to 51.2 items per m3 or from 79.4 to 87.5 μg per m3 in the Tom River and in the Ob River, correspondingly. 93.5% of recovered microplastics were less than 1 mm in their largest dimension, the largest group (45.5% of total counts) consisted of particles with sizes range 0.30-1.00 mm

An evaporation-based model of thermal neutron induced ternary fission of plutonium

Ternary fission probabilities for thermal neutron induced fission of plutonium are analyzed within the framework of an evaporation-based model where the complexity of time-varying potentials, associated with the neck collapse, are included in a simplistic fashion. If the nuclear temperature at scission and the fission-neck-collapse time are assumed to be ~1.2 MeV and ~10^-22 s, respectively, then calculated relative probabilities of ternary-fission light-charged-particle emission follow the trends seen in the experimental data. The ability of this model to reproduce ternary fission probabilities spanning seven orders of magnitude for a wide range of light-particle charges and masses implies that ternary fission is caused by the coupling of an evaporation-like process with the rapid re-arrangement of the nuclear fluid following scission.Comment: 25 pages, 12 figures, accepted for publication in IJMP

Hydrobionts of a freshwater oil-polluted northern lake: bioaccumulation of heavy metals in fish and the rate of ecosystem recovery

The response of phytoplankton, zooplankton, benthic and fish community structure to one of the biggest oil spill in history of Komi Republic (north-west part of Russia) was investigated using data from a long-term survey off the polluted lake. The characteristics of aquatic freshwater communities observed in the study area 10, 11 and 22 years after the spill (1994) were compared to find out the rate of natural recovery of the ecosystem after oil decontamination of bottom sediments. The concentrations of fifteen trace metals (Al, Cr, Fe, Co, Ni, Cu, Zn, As, Mo, Cd, Sb, Pb, U, Bi, Th) were analyzed in the tissues (muscle) of three fish species. The concentrations of Al (3-309 mg/kg), Cr (0,1-3,71 mg/kg), Fe (8,6-317 mg/kg), and Cu (0,09-99 mg/kg) in fishes from polluted lake resulted in most cases higher than reference thresholds. Quantitative and qualitative indicators of aquatic invertebrates from polluted lake reach those one of unpolluted lake but do not fully recover 22 years after the spill, despite that oil concentration in water column and in bottom sediments was lower than reference tresholds. We conclude that natural recovery rate of aquatic freshwater ecosystems in northern regions after oil pollution is extremely low. The purification of water and bottom sediments of oil-polluted northern water bodies is necessary for stimulation of ecosystem restoration

Beam halo dynamics and control with hollow electron beams

Experimental measurements of beam halo diffusion dynamics with collimator scans are reviewed. The concept of halo control with a hollow electron beam collimator, its demonstration at the Tevatron, and its possible applications at the LHC are discussed.Comment: 5 pages, 4 figures, in Proceedings of the 52nd ICFA Advanced Beam Dynamics Workshop on High-Intensity and High-Brightness Hadron Beams (HB2012), Beijing, China, 17-21 September 201

Technological features of manufacturing an arched gears

Розглянуто технологічні особливості виготовлення та умови обробки загартованих аркових циліндричних зубчастих передач і арочних конічних передач з зачепленням М. Л. Новікова. Розроблена методика вибору конструкторсько-технологічних вимог аркових передач і система “РНС-1” геометричного розрахунку циліндричних, конічних і рейкових передач з арковими зубцями, а також уніфікація і скорочення номенклатури засобів виробництва. Проведені стендові випробування арочних зубчастих передач дозволили створити універсальний ріжучий інструмент з круглими незатылованными різцями.Purpose. Technological peculiarities of production and conditions of hardened cylindrical arched gears and arched bevel gears with meshing M. L. Novikova. Design/methodology/approach. Developed methodology for selection of design and technological requirements of the arched guide and the system "IR-1" geometric calculation of cylindrical, bevel and pinion gear with arched teeth, as well as unification and reduction of the range of the means of production. Bench tests of the arched gear has allowed us to create a versatile cutting tool with a round niesatynowany cutters. Conical spur, helical and herringbone gear, along with the advantages are inherent operational and technological disadvantages and in some cases do not satisfy the increasing requirements of modern gears to ensure smoothness, durability, reliability. The purpose of the design and process conditions for manufacturing an arched gears. Study of the technological features of manufacturing arched teeth at the present time is a real reserve for further enhancing the efficiency of gears and means for their production. Findings. Arched teeth allow to increase the load capacity of 1.25-1.5 times and durability in 2 - 3 times a cylindrical and a rack and pinion transmission, to reduce vibration, noise characteristics, intensity and cost. Originality/value. Arched teeth allow you to create a single technological system tools for the production of cylindrical, bevel and pinion gears provide smooth transmission of motion and can find application in high-speed high-load transmission.Рассмотрены технологические особенности изготовления и условия обработки закаленных цилиндрических арочных зубчатых передач и арочных конических передач с зацеплением М.Л. Новикова. Разработана методика по выбору конструкторско-технологических требований арочных передач и система “РНС-1” геометрического расчета цилиндрических, конических и реечных передач с арочными зубьями, а также унификация и сокращение номенклатуры средств производства. Проведенные стендовые испытания арочных зубчатых передач позволили создать универсальный режущий инструмент с круглыми незатылованными резцами

Charm production nearby threshold in pA-interactions at 70 GeV

The results of the SERP-E-184 experiment at the U-70 accelerator (IHEP, Protvino) are presented. Interactions of the 70 GeV proton beam with C, Si and Pb targets were studied to detect decays of charmed $D^0$, $\overline D^0$, $D^+$, $D^-$ mesons and $\Lambda _c^+$ baryon near their production threshold. Measurements of lifetimes and masses are shown a good agreement with PDG data. The inclusive cross sections of charm production and their A-dependencies were obtained. The yields of these particles are compared with the theoretical predictions and the data of other experiments. The measured cross section of the total open charm production ($\sigma _{\mathrm {tot}}(c\overline c)$ = 7.1 $\pm$ 2.3(stat) $\pm$1.4(syst) $\mu$b/nucleon) at the collision c.m. energy $\sqrt {s}$ = 11.8 GeV is well above the QCD model predictions. The contributions of different species of charmed particles to the total cross section of the open charm production in proton-nucleus interactions vary with energy.Comment: 4 pages, 6 pages, 38th International Conference on High Energy Physics 3-10 August 2016, Chicago, US