DANSS is a highly segmented 1 m3 plastic scintillator detector. Its 2500 one meter long scintillator strips have a Gd-loaded reflective cover. The DANSS detector is placed under an industrial 3.1 ...GWth reactor of the Kalinin Nuclear Power Plant 350 km NW from Moscow. The distance to the core is varied on-line from 10.7 m to 12.7 m. The reactor building provides about 50 m water-equivalent shielding against the cosmic background. DANSS detects almost 5000 ν˜e per day at the closest position with the cosmic background less than 3%. The inverse beta decay process is used to detect ν˜e. Sterile neutrinos are searched for assuming the 4ν model (3 active and 1 sterile ν). The exclusion area in the Δm142,sin22θ14 plane is obtained using a ratio of positron energy spectra collected at different distances. Therefore results do not depend on the shape and normalization of the reactor ν˜e spectrum, as well as on the detector efficiency. Results are based on 966 thousand antineutrino events collected at three different distances from the reactor core. The excluded area covers a wide range of the sterile neutrino parameters up to sin22θ14<0.01 in the most sensitive region.
The results of numerical simulation of chemical-thermal treatment, namely, heating of a massive metal container with a working medium and a small-sized titanium disk sample, are presented. To study ...the heating kinetics of this system, the effect of the parameters of chemical-thermal treatment, in particular the inductor current from 3.4 to 8 kA at a frequency of 90 kHz, was determined.
In this work, the relationship between the parameters of voltage, inductor current, duration, temperature of induction heat treatment and the hardness of commercial purity titanium was studied. As a ...result, the temperature ranges at a fixed voltage and current of the inductor were established. At certain technological conditions, with various durations of heat treatment, the hardness of the titanium surface was determined.
An agrometeorollological assessment of five oat varieties (Megion, Talisman, Otrada, Foma, Tobolyak) of the breeding of the Northern Trans-Urals Research Institute of Agriculture - branch of the ...TyumSC SB RAS is given. The effect of the average daily air temperature and precipitation on the growth and development of plants has been established. The sensitivity of varieties to temperature is estimated. It was found that the optimal average daily air temperature during the sprout – ear emergence period was 16.4 … 16.8°C, during the ear emergence – waxy ripeness period - 17.5…19.4°C. The sums of effective temperatures over 10°C necessary for optimal growth and development of oat varieties are calculated. Varieties Megion, Talisman, Foma and Tobolyak in the period of sprout – ear emergence required a greater amount of effective temperatures (705.2…747.0°C) than in the period of ear emergence - wax ripeness (611.2…640.2°C). In the Otrada variety, the need for heat was slightly higher in the second interphase period (717.5°C) compared to the first (705.6°C). The optimal amount of precipitation required for the formation of a high yield (189.4…243.6 mm) is calculated. To realize the genetic potential of the Talisman and Otrada varieties, most of the precipitation is necessary during the sprout – ear emergence period, and the Megion, Foma and Tobolyak varieties - during the period of ear emergence - waxy ripeness.
In this work, the process of induction heating of a container with a titanium sample in a carbon-containing medium was simulated using the finite element method. The dependence of the inductor ...current I and the duration of treatment on the heating kinetics T(I,t) of the "inductor - container - sample" system taking into account the heat losses QL(I, T) on the process of chemical-thermal treatment of titanium was established.
Abstract
The results of the chemical thermal treatment (CTT) of tantalum in a solid carbon- containing medium in the temperature range from 1000 to 1300 °C were presented. CTT consisted in heating a ...workpiece with a working medium in a container made of a refractory material. The induction heating method was used for heating. After strengthening treatment, tantalum samples were characterized by increased hardness, which grew from 140 to 1100 HV
0.02
.
Abstract
The changes in the surface area of titanium samples occurring during induction heat treatment (IHT) were studied. The dependence of the surface area of titanium samples on the exposure ...temperature was revealed. When a titanium sample was heated to a temperature of 1000 °C in the air at an exposure time of 60 s, there was a 45-fold area increase. The assessment of the porosity of the formed coating is carried out. The number of pores increased with increasing temperature from 374 to 1029 pieces. Accordingly, the average pore size decreased by 40%.
The DANSS detector (Alekseev et al. in JINST 11:P11011, 2016) is located directly below a commercial reactor core at the Kalinin Nuclear Power Plant. Such a position provides an overburden about 50 ...m.w.e. in vertical direction. In terms of the cosmic rays it occupies an intermediate position between surface and underground detectors. The sensitive volume of the detector is a cubic meter of plastic scintillator with fine segmentation and combined PMT and SiPM readout, surrounded by multilayer passive and active shielding. The detector can reconstruct muon tracks passing through its sensitive volume. The main physics goal of the DANSS experiment implies the antineutrino spectra measurements at various distances from the source. This is achieved by means of a lifting platform so that the data is taken in three positions – 10.9, 11.9 and 12.9 meters from the reactor core. The muon data were collected for nearly four calendar years. The overburden parameters
⟨
E
thr
cos
θ
⟩
and
⟨
E
thr
⟩
, as well as the temperature and barometric correlation coefficients are evaluated separately for the three detector positions and, in each position, in three ranges of the zenith angle – for nearly vertical muons with
cos
θ
>
0.9
, for nearly horizontal muons with
cos
θ
<
0.36
, and for the whole upper hemisphere.
This work investigates the ability of ericoid mycorrhizal (ErM) and ectomycorrhizal (EcM) fungi to solubilize different toxic metal (Cd, Cu, Pb, Zn)-containing minerals. Minerals were incorporated ...into solidified agar media and solubilization assessed by measuring clearing of the agar after fungal growth. Measurement of radial growth and biomass dry weight provided indications of metal tolerance: accumulated metal in the biomass was measured by atomic absorption spectrophotometry. Metal tolerance and solubilizing ability varied widely between different mineral and fungal species, and strains derived from sites of differing degrees of metal pollution. Zinc phosphate exhibited the least toxicity and was the easiest to solubilize by the majority of tested fungal isolates. Solubilization of toxic metal minerals was connected with both the pH of the medium and growth and tolerance of fungi and it seems that acidification of the medium was the main mechanism of mineral dissolution for most of the mycorrhizal fungi studied. A very strong lethal effect was observed for ectomycorrhizal isolates (>60% of strains) in the presence of Pb phosphate, carbonate, sulphide and tetraoxide. In contrast, ericoid mycorrhizal isolates were able to grow on Pb-mineral-amended media. A significant proportion of ericoid mycorrhizal cultures (70–90%) solubilized Cd and Cu phosphates and cuprite. None of the ericoid mycorrhizal and ectomycorrhizal fungi were able to produce a clear zone in Pb mineral-containing agar. However, many fungi were able to accumulate mobilized Pb in their mycelia. Differences in toxic metal mineral tolerance, mineral solubilization and metal uptake between populations isolated from metal-polluted and uncontaminated sites were related to the toxic metal which was the main pollutant in the original contaminated environment. In general, metal-tolerant fungi grew and solubilized toxic metal minerals better than non-tolerant isolates.
The fungus Beauveria caledonica was highly tolerant to toxic metals and solubilized cadmium, copper, lead, and zinc minerals, converting them into oxalates. This fungus was found to overexcrete ...organic acids with strong metal-chelating properties (oxalic and citric acids), suggesting that a ligand-promoted mechanism was the main mechanism of mineral dissolution. Our data also suggested that oxalic acid was the main mineral-transforming agent. Cadmium, copper, and zinc oxalates were precipitated by the fungus in the local environment and also in association with the mycelium. The presence of toxic metal minerals often led to the formation of mycelial cords, and in the presence of copper-containing minerals, these cords exhibited enhanced excretion of oxalic acid, which resulted in considerable encrustation of the cords by copper oxalate hydrate (moolooite). It was found that B. caledonica hyphae and cords were covered by a thick hydrated mucilaginous sheath which provided a microenvironment for chemical reactions, crystal deposition, and growth. Cryo-scanning electron microscopy revealed that mycogenic metal oxalates overgrew parental fungal hyphae, leaving a labyrinth of fungal tunnels within the newly formed mineral matter. X-ray absorption spectroscopy revealed that oxygen ligands played a major role in metal coordination within the fungal biomass during the accumulation of mobilized toxic metals by B. caledonica mycelium; these ligands were carboxylic groups in copper phosphate-containing medium and phosphate groups in pyromorphite-containing medium.
PDF
