The paper describes two Monte Carlo codes dedicated to muon simulations: MUSIC (MUon SImulation Code) and MUSUN (MUon Simulations UNderground). MUSIC is a package for muon transport through matter. ...It is particularly useful for propagating muons through large thickness of rock or water, for instance from the surface down to underground/underwater laboratory. MUSUN is designed to use the results of muon transport through rock/water to generate muons in or around underground laboratory taking into account their energy spectrum and angular distribution.
The data on the content of cosmogenic isotopes 14C and 10Be in the Earth's atmosphere at a time interval of 15000-5000 BC were analyzed. On Earth at this time there was a transition from the ice age ...to the Holocene. The reconstruction of Wolf numbers based on radiocarbon data is presented, which describes solar activity and takes into account changes in the Earth's climate during the period under consideration. The increase in global temperature during the transition to the Holocene was accompanied by a sequence of warming (for example, Meiendorf warming) and cooling. The obtained reconstruction of Wolf numbers indicates that at separate time intervals: 13600-13000, 9300-9000, 8300-8000 BC the Sun was in a state of deep minima of activity. We also note the activity minima at ≈ 10700 and 7500 BC. The periods of extremely high activity of the Sun were also distinguished, so at maxima ≈ 12350 and 6715 BC. Values of Wolf numbers could exceed 200. The duration of the first of these periods was several hundred years, and at that time Meiendorf warming took place on Earth (≈12500-11850 BC). The question arises: are these events related?
•Influence of thin polymer coating on the high-velocity impact resistance of multilayer aramid fabrics was examined.•An average areal density increasing for coated fabric did not exceed 6%.•Specimens ...based on coated fabrics can absorb three times as much projectile kinetic energy without perforation.•Yarn-level numerical models allow to predict plasticine indentation dept after a step-by-step calibration procedure.
Composites based on aramid fibres are widely used to protect people and vehicles from high-velocity impact threats. Currently, quite a lot of attention is paid to methods for increasing the efficiency of such structures without a significant increase in areal density. The article demonstrates the results of experimental and computational studies of two types of multilayer fabric systems based on Twaron® 709. The first system consisted of dry fabric layers, and the second one was based on the fabric layers with polyvinyl acetate (PVA) surface coating. Experimental studies included quasi-static yarn pull-out tests, high-velocity impact tests of specimens without backing support, and tests on a plasticine block to assess the back face bulging. The results of the experiments showed that thin coatings of PVA contributed to a significant pull-out force increase due to polymer connections between the yarns. This effect led to the fact that specimens based on coated fabrics had a ballistic limit twice as much and showed a three-fold decrease in the depth of the dent on plasticine in comparison with dry fabrics. The total increase in surface density did not exceed 6% while maintaining high flexibility of the package. Also, numerical simulations were used to confirm the results of experiments. It was shown that mesoscale yarn-level models allow to predict plasticine indentation depths of the dry and coated multilayer fabric targets.
We present the results of measurements demonstrating the efficiency of the EDELWEISS-III array of cryogenic germanium detectors for direct dark matter searches. The experimental setup and the FID ...(Fully Inter-Digitized) detector array is described, as well as the efficiency of the double measurement of heat and ionization signals in background rejection. For the whole set of 24 FID detectors used for coincidence studies, the baseline resolutions for the fiducial ionization energy are mainly below 0.7 keVee (FHWM) whereas the baseline resolutions for heat energies are mainly below 1.5 keVee (FWHM). The response to nuclear recoils as well as the very good discrimination capability of the FID design has been measured with an AmBe source. The surface β- and α-decay rejection power of Rsurf<4×10−5 per α at 90% C.L. has been determined with a 210Pb source, the rejection of bulk γ-ray events has been demonstrated using γ-calibrations with 133Ba sources leading to a value of Rγ−mis−fid<2.5×10−6 at 90% C.L.. The current levels of natural radioactivity measured in the detector array are shown as the rate of single γ background. The fiducial volume fraction of the FID detectors has been measured to a weighted average value of (74.6±0.4)% using the cosmogenic activation of the 65Zn and 68,71Ge isotopes. The stability and uniformity of the detector response is also discussed. The achieved resolutions, thresholds and background levels of the upgraded EDELWEISS-III detectors in their setup are thus well suited to the direct search of WIMP dark matter over a large mass range.
The heliospheric modulation potential is reconstructed for the period from 12 000 to 8000 BC based on the content of the cosmogenic isotope
10
Be in layers of the GISP2 ice core of the Greenland Ice ...Sheet. The results are compared with the heliospheric modulation potential reconstructed earlier from radiocarbon data and with data on climate change. In particular, we show that the cooling during the Younger Dryas (~10 700–9700 BC) may have caused by low solar activity. Two periods of high solar activity are distinguished at the early Holocene, near 9600–9400 and 8900–8400 BC, which indicates the possible effect of variations in the solar activity on the Earth’s climate change.
The issues of the current state of water bodies in the Russian Federation are considered and their comparative characteristic with other countries, mainly Western European ones, is given. By a ...resolution adopted by the UN General Assembly in 2018, a system of global indicators for achieving the Sustainable Development Goals and targets for the period up to 2030 was approved, and one of these targets is devoted to the state of water bodies. Despite large water resources, Russia already has serious problems with the quality of water in water bodies and the degree of financing of water protection measures. The water quality of such rivers as the Neva and the Volga was very high a few decades ago, but now it causes serious concerns. For some ingredients, the concentration of pollutants exceeds the maximum allowable concentrations hundreds of times. Since the 1990s and up to the present time, the relative financing of water protection measures (as a percentage of GDP) in the Russian Federation has been constantly decreasing. The efficiency of the use of financial resources is also decreasing.
The EDELWEISS-II Collaboration has completed a direct search for WIMP dark matter with an array of ten 400-g cryogenic germanium detectors in operation at the Laboratoire Souterrain de Modane. The ...combined use of thermal phonon sensors and charge collection electrodes with an interleaved geometry enables the efficient rejection of γ-induced radioactivity as well as near-surface interactions. A total effective exposure of 384 kg d has been achieved, mostly coming from fourteen months of continuous operation. Five nuclear recoil candidates are observed above 20 keV, while the estimated background is 3.0 events. The result is interpreted in terms of limits on the cross-section of spin-independent interactions of WIMPs and nucleons. A cross-section of 4.4×10−8 pb is excluded at 90%CL for a WIMP mass of 85 GeV. New constraints are also set on models where the WIMP-nucleon scattering is inelastic.
Abstract
This work examines the change in the activity of the Sun based on the reconstruction of the heliospheric modulation potential in the time interval 8000 - 1000 BC. Reconstructions of this ...potential were obtained using radiocarbon data, taking into account the influence of changes in the Earth’s climate. A comparison is made of the variations in the activity of the Sun with the global surface temperature. It is shown that variations in global temperature during this period could be the result of changes in solar activity. So high solar activity could lead to recorded temperature maximums around 7000 and 5300 BC. The drop in temperature in the range 3000-1000BC could be the result of low solar activity.
Current challenges in the development of various polymer nanocomposites and in the study of their properties are considered. Results of studying hybrid structural (polymer - layered silicates, ...polymer - nanodiamonds) and functional (based on conducting or liquid-crystalline polymers) nanomaterials are presented. Methods of modification of nanoparticles and their dispersion in a polymer matrix, and the role of interactions between a polymer matrix and fillers, as well as of nanoparticle morphology realized in the course of processing, are discussed. The bibliography includes 453 references.
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