We present the results of in situ measurements of 134Cs and 137Cs released from the Fukushima Nuclear Power Plant (FNPP) collected at surface and different depths in the western North Pacific in June ...and July 2012. It was found that 15 month after the incident concentrations of radiocesium in the Japan and Okhotsk seas were at background or slightly increased level, while they had increased values in the subarctic front area east of Japan. The highest concentrations of 134Cs and 137Cs up to 13.5±0.9 and 22.7±1.5Bqm−3 have been found to exceed ten times the background levels before the accident. Maximal content of radiocesium was observed within subsurface and intermediate water layers inside the cores of anticyclonic eddies (100–500m). Even slightly increased content of radiocesium was found at some eddies at depth of 1000m. It is expected that convergence and subduction of surface water inside eddies are main mechanisms of downward transport of radionuclides. In situ observations are compared with the results of simulated advection of these radioisotopes by the AVISO altimetric velocity field. Different Lagrangian diagnostics are used to reconstruct the history and origin of synthetic tracers imitating measured seawater samples collected in each of those eddies. The results of observations are consistent with the simulated results. It is shown that the tracers, simulating water samples with increased radioactivity to be measured in the cruise, really visited the areas with presumably high level of contamination. Fast water advection between anticyclonic eddies and convergence of surface water inside eddies makes them responsible for spreading, accumulation and downward transport of cesium rich water to the intermediate depth in the frontal zone.
•Fukushima-derived cesium-isotopes have been detected in the centers of anticyclonic eddies in the western North Pacific.•Maximal concentrations have been observed in the subsurface and intermediate waters as a result of subduction at the eddies.•The observations have been found to be consistent with simulation based on AVISO velocity field.•Lagrangian diagnostics were used to reconstruct origin of tracers imitating seawater samples collected in the eddy cores.
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•Three amino acid-fullerene60-pyropheophorbide a dyads (AFD-PPa) were synthesized.•AFD-PPa dyads form nanoassociates in water as a result of self-assembly.•Photodynamic mechanism ...switching from type II of dye to I type of dyad was shown.•All dyads have a pronounced phototoxicity on HeLa cancer cells.
Synthesis, spectral properties, and photodynamic activity of water-soluble amino acid fullerene C60 derivatives (AFD) and four original AFD-PPa dyads, obtained by covalent addition of dye pyropheophorbide (PPa) to AFD, were studied. In aqueous solution, these AFD-PPa dyads form nanoassociates as a result of self-assembly. In this case, a significant change in the absorption spectra and strong quenching of the dye fluorescence in the structure of the dyads were observed. A comparison of superoxide or singlet oxygen generation efficiency of the studied compounds in an aqueous solution showed the photodynamic mechanism switching from type II (singlet oxygen generation of the native dye) to I type (superoxide generation of dyads). All dyads have pronounced phototoxicity on cells Hela with IC50 9.2 µM, 9.2 µM, 12.2 µM for dyads Val-C60-PPa, Ala-C60-PPa and Pro-C60-PPa, respectively. Such facilitation of type I photodynamic mechanism could be perspective against hypoxic tumors.
The paper presents the results of calculations of the sampling fluctuations in Pb–LAr electromagnetic sandwich calorimeters. The GEANT4 package was used to generate showers initiated by electrons ...with energies
E
0
from 20 to 500 GeV. It is shown that the dependence of the sampling fluctuations on
E
0
and the thickness of the lead absorber
x
can be described by the formula
kx
b
/
. The exponent
b
weakly depends on the LAr gap width
d
and is close to 2/3 and
k
= 0.1985−0.0363ln
d
mm.
Abstract
In article research of human biomechanics is carried out in the case of registering his movements using a single accelerometer, which is located in a wearable device. Mobile phones, smart ...watches or fitness bracelets can act as a wearable device. It should be noted that the research is oriented at evaluating biomechanics using a mobile phone, but the results obtained in the form of algorithms and a general approach can be transferred to cases of using other wearable devices.
Abstract
The article considers the possibility of biometric authentication based on gait parameters, which are obtained after intelligent processing of the accelerometer data of a wearable device. ...The article discusses the main trends and trends in the field of biometric authentication, as well as authentication by gait parameters. The developed neural network algorithm and informative parameters are described in the authentication procedure based on the data of a single sensor of a portable device. The practical verification of the proposed approach is carried out on 32 subjects of different physiology. The results of the study show the possibility of distinguishing their own movements in 100% of cases, and the distinction of the subjects is more than 90%. Also, the final part of the article provides the requirements for the authentication procedure when processing accelerometric data of gait biometrics, the level of trust of the developed algorithm is determined.
The Lewis basicity of typical electron donor compounds used to modify heterogeneous Ziegler–Natta catalysts, such as diakyl ethers, silyl ethers, esters, and ketones, was characterized by determining ...their effects on the IR frequency of surface silanol groups of silica gel, which correlate with the heat of this specific interaction and with their “donicity”, i.e., with the heat of formation of their complexes with SbCl5. In this manner, ethers and silyl ethers are found to be more basic than ketones and esters. These differences in basicity are likely to affect the stereoregulating properties of such electron donor compounds in Ziegler–Natta polymerization catalysis. By consecutively adsorbing electron donors with various strengths on a MgCl2 support, it was shown that weakly basic donors, such as ethyl benzoate or dibutyl phthalate, are partially displaced by donors with higher basicity, such as valerophenone and propyltrimethoxysilane. This indicates that the displacement of inner donors of the ester type from a titanium–magnesium catalyst upon addition of typical external donors, such as silyl ethers, is controlled by the relative basicities of these donor molecules.
The results of calculations of the charged particles multiplicity, energy, radial and time distributions in the electromagnetic showers initiated by electrons with energies from 5 to 1000 GeV in Fe, ...W and Pb are presented. It is shown that the multiplicity distributions are well fitted by the inverse sum of two exponents in a wide range of energy and lead depth. The shapes of energy and radial distributions at the shower maximum weakly depend on the electron energy. Radial distributions for all materials studied are similar if radius is expressed in g/cm2. The time spread of the charged particles at the shower maximum turned out to be in the picosecond range.
The results of the calculations of coordinate resolution and hadron rejection factor for a simple
е
/γ detector consisting of a lead converter followed by a hodoscope are presented. For the ...simulation of showers, initiated in the converter by electrons and hadrons with energies up to 1 TeV GEANT4 is used. It is shown that the best coordinate resolution for electrons is achieved when the converter thickness is closed to the position
t
max
of the shower maximum
.
For example, at 200 GeV with 2 mm strip width hodoscope it is equal to σ = 89 μm provided a “truncated mean” coordinate estimation is used. The optimal thickness of the converter for hadron rejection is also close to
t
max
. For 200 GeV beam of electrons and protons the rejection factor of 10
–4
for 0.9 electron detection efficiency can be reached using only data on charged particles multiplicities. Information on the spatial distribution of the shower particles after the converter allows to enhance further the rejection by several times.
Charged particles multiplicity distributions at the maximum of electromagnetic showers initiated by 5–1000 GeV electrons in Fe, W, and Pb were calculated using GEANT4. It is shown that they are well ...fitted by the inverse sum of two exponents and the energy dependence of the average multiplicity follows power law with the power of ~0.95 for all materials.
Abstract
This paper researches the effectiveness of heap leaching for processing the sulfide raw materials in Murmansk Oblast. It studies the kinetics of how metals are extracted into the solution, ...as well as the peculiarities of chalcopyrite dissolution. The paper shows that leaching destroys the grains, making them into fine particulate matter, which ultimately jeopardizes solution filtering. Use of recycled solution makes the leaching process more cost-effective.
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