The description of Dynamic Albedo of Neutrons (DAN) experiment is presented, as a part of the NASA’s Mars Science Laboratory mission onboard the mars rover Curiosity. The instrument DAN includes ...Pulsing Neutron Generator (PNG) producing pulses of 14.1 MeV neutrons for irradiation of subsurface material below the rover, and Detectors and Electronics (DE) unit, which operates the instrument itself and measures the die-away time profiles of epithermal and thermal neutrons following each neutron pulse. It is shown that the DAN investigation will measure a content of hydrogen along the path of the MSL rover, and it will also provide information about a depth distribution of hydrogen at 10–20 regions selected for the detailed studies and sampling analysis.
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The study of the elemental composition of labile humus substances passing into 0.1 M NaOH extract from typical chernozem under different cenoses indicated that, judging from the H : C ratio varying ...within 1.55–1.91, aliphatic structures predominate over cyclic components. Under the agrogenic impact, the processes demethylation, dehydrogenation, and oxidation of organic substances are developed in the chernozem. As a result, labile humic substances lose their aliphatic components and become enriched with oxidized nitrogen-containing cyclic structures. The intensity of this process increases in the series: permanent winter wheat > permanent corn > permanent bare fallow. At the same time, labile humic substances of the chernozem under permanent bare fallow are the least energy-intensive compounds as judged from the values of the heat of combustion found on the basis of elemental analysis data. Over the 23 years that have passed since the transfer of the permanent bare fallow to the unmanaged fallow overgrown by herbs, there have been no significant changes in the elemental composition of labile humus substances of typical chernozem, except for a tendency of their enrichment in newly formed aliphatic nitrogen-containing reduced and more energy-intensive compounds.
•D plasma ions impact on BMG leads to D absorption and modification of some properties.•At D ion energy< 120 eV, the amount of D absorbed increases linearly with ion fluence.•At D ion energy> 450 eV, ...the sputtering process dominates.•Plane BMG samples exposed in D plasma are bent due to D trapping in near-surface layer.
Samples of two kinds of bulk metallic glasses (BMG) with different compositions, Zr48Cu36Al8Ag8 and Zr57Cu15.4Al10Ni12.6Nb5, were polished to mirror-like quality and, after measuring the initial reflectance at normal light incidence, were subjected to impact of ions of deuterium or argon plasma with fixed energy. The main attention was paid to phenomenon on deuterium absorption that reveals as the weight gain after every exposure of the samples in deuterium plasma. For a fixed ion energy (in the range<100 eV), the amount of absorbed deuterium increased linearly with increasing of the ion fluence. Bending of the samples was observed when one side of sample was bombarded by deuterium plasma ions. At that, the radius of curvature of samples was decreasing with increasing the amount of trapped deuterium in such a way that its curvature was increasing proportionally to the amount of trapped deuterium. This is an evidence of near-surface distribution of the trapped deuterium. The results demonstrate that D ions within a fluence of ∼2·1025 ions/m2 are initially accumulated in a thin near-surface layer of the samples. Further, they are noted effects of stress relaxation and of deuterium redistribution.
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The humus-accumulative horizon of a typical chernozem (Haplic Chernozem (Loamic, Pachic)) under different land uses has been studied with the thermal method and IR spectroscopy. According to our ...data, the organic matter of chernozem mainly consists of thermally weakly stable aliphatic compounds, such as polysaccharides. This is indicated by a considerable weight loss (68.15–71.54%) in the low-temperature region, which varies and an intense absorption band at 1083 cm
–1
, which determines the shape of the IR spectra of chernozem. An extensive agricultural use has caused the mineralization of labile aliphatic compounds and an increase in stable cyclic structures in the composition of the organic matter of chernozem. This is indicated by a decrease in the Chernikov–Konchits
Z
coefficient from 3.16 to 2.47–2.73 and in the intensity of most absorption bands in the IR spectra. The most pronounced negative impact on the organic matter of a typical chernozem is caused by bare fallow.
In the work, the possibility of using microturbine plants to cover auxiliary needs in the electric and thermal energy of complexes for the processing of municipal solid waste, as well as in hydrogen ...production plants when oxidizing powdered aluminum with water. There were proposed basic thermal diagrams of power units. There were given justification for the choice of wet-steam microturbines, which provide a higher ratio between thermal and electric power, as well as the possibility of their separate regulation in comparison with gas turbine and gas piston units. There were analyzed the working process of a single-stage two-stream active centripetal steam microturbine with an electric power of 50 kW (600 kW - thermal), which was developed, manufactured and tested, both at idle and under load as part of energy technology complexes for the disposal of municipal and agricultural solid waste. Tests showed a reduced blade efficiency of the radial microturbine compared to the calculated one. There were carried out analysis of possible causes of discrepancy and measures were developed to achieve the declared characteristics by subsequent samples of turbogenerators.
The paper considers the task of creating an instrumental system for optimizing the exchange of active power of the trunk and distribution networks, taking into account the price indicators of ...electricity in a joint and separate mode of operation. As part of the development of a simulation model of the automated control system of the local intelligent power system MicroGrid, the results of modeling the exchange of active power of the power connection from the main network of the main South of Russia main electrical networks and the distribution network of the university campus (in which classical sources of generation are combined with solar, wind and hydrogen energy) are presented.
In a single model, the electrical mode of operation of networks is simulated in the voltage range of 0.4–500 kV. Simulation is carried out in steady state and transient mode. Slow, real and fast time modes are available. Simulation of emergency control systems has been implemented. The modes of synchronization of the main and distribution networks in normal and emergency circuits are considered. Reliability control and monitoring of the main operating parameters are carried out.
The active power exchange module created on the basis of the results of the simulation as part of the software package « RETREN » will make it possible to use this complex to automate the management of local power system. The energy system, in addition to power from the grid, includes gas generation, solar panels installed on the roofs of campus buildings, wind turbines and stationary hydrogen power plants operating on hydrogen fuel cells. The complex of designers allows organizing human-machine interfaces of any complexity on completely domestic software products.
We present our experimental results on the compressibility of strongly coupled (nonideal) degenerate deuterium and helium plasmas quasi-isentropically compressed to pressures
P
~ 20 TPa in devices ...with a spherical geometry. The trajectories of the plasma-compressing metallic shells were recorded with the help of powerful pulsed X-ray sources (betatrons) with a boundary electron energy of 60 MeV. A high-current accelerator with a penetrability of objects with an equivalent thickness of 250-mm of lead has been used for the first time as an X-ray source in our experiments. Plasma densities up to ρ ≈ 14 g cm
–3
were determined from the measured radius of the shell at the instant of its “stopping.” We derived the compressed-plasma pressure based on our gasdynamic computations including the real characteristics of the experimental devices.
Polycrystalline diamond coatings have been grown on cemented carbide WC-6% Co substrates with different aspect ratios by microwave plasma CVD in CH4/H2 gas mixtures. Special plateholder with holes ...for group growth has been used to protect the edges of the substrates from non-uniform heating due to the plasma edge effect. The difference in heights Δh of the substrates and plateholder, and its influence on the diamond film mean grain size, growth rate, phase composition and stress was investigated. Diamond growth rate of 0.3–1μm/h and compressive stress of 2.2–2.5GPa, respectively were determined in the optimal Δh region. The substrate temperature range of 740–760°C, within which uniform diamond films are produced with good adhesion, is determined. The diamond-coated samples produced at optimized process conditions exhibited a reduction of cutting force and wear resistance by a factor of two, and increase of cutting path length up to 8150m or by 4.3 times upon turning А390 Al-Si alloy as compared to performance of uncoated tools.
Polycrystalline diamond coatings with uniform structure and thickness distribution are grown by microwave plasma CVD (MPCVD) on WC-6% Co substrates using an optimized pocket-type substrate holder. Edge effect during MPCVD on high substrates (height/diameter>0.1) was suppressed. Influence of distance between the substrate holder and substrate surface on deposition temperature and other parameters was investigated. Cutting force and wear rate of the coated samples upon cutting of Si-Al abrasive alloy were twice less than that of uncoated WC-6% Co.
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•Substrate holder for simultaneous MPCVD of diamond on some thick substrates is applied.•Effect of distance between the holder and the substrate surface on MPCVD is investigated.•Coatings with uniform thickness and grain size are produced using this substrate holder.•Diamond-coated WC-6% Co thick substrates are tested upon cutting of A390 Si-Al alloy.•Cutting force and wear rate are strongly reduced for the diamond-coated substrate.
An apparatus for the rapid thermal extraction of Re radioisotopes from an irradiated tungsten target has been developed. Its operation was tested using a tungsten target pre-irradiated with deuterons ...on the U-150 cyclotron of the Kurchatov Institute. A description of the design of the apparatus and the principle of its operation are given. It has been shown that in one two-stage calcination–sublimation cycle, at least 89% of the Re activity from the W target can be collected on the receiving area of the collector. The apparatus can be used to isolate the
186
Re isotope formed from
186
W upon irradiation with protons or deuterons of cyclotron targets.
The present paper discusses results of full-scale experimental and numerical investigations of influence of construction materials of portable pulsed neutron generators ING-031, ING-07, ING-06 and ...ING-10-20-120 (VNIIA, Russia) to their radiation characteristics formed during and after an operation (shutdown period). In particular, it is shown that an original monoenergetic isotropic angular distribution of neutrons emitted by TiT target changes into the significantly anisotropic angular distribution with a broad energy spectrum stretching to the thermal region. Along with the low-energetic neutron part, a significant amount of photons appears during the operation of generators. In the pulse mode of operation of neutron generator, a presence of the construction materials leads to the “tailing” of the original neutron pulse and the appearance of an accompanying photon pulse at ~3ns after the instant neutron pulse. In addition to that, reactions of neutron capture and inelastic scattering lead to the creation of radioactive nuclides, such as 58Co, 62Cu, 64Cu and 18F, which form the so-called activation radiation. Thus, the selection of a portable neutron generator for a particular type of application has to be done considering radiation characteristics of the generator itself. This paper will be of interest to users of neutron generators, providing them with valuable information about limitations of a specific generator and with recommendations for improving the design and performance of the generator as a whole.
