The daily activity of four mass species of small mammals from the forest zone of three biotopes differing greatly in their protective properties is compared using the marking method with live traps ...arranged in lines. Live-trap lines were established in a dark coniferous forest, on a grassy slope, and along a rocky beach along the water edge on the Ilych River. The activity of resident and nonresident individuals was assessed with a checking frequency of 1.5 h. In the forest, a polyphasic activity without pronounced maxima has been recorded for all species; on the open slope, the maximum activity of resident animals is observed at night and only nonresident animals were recorded on the bank. Nonresident activity in all biotopes is shifted to night time; in open biotopes, the period of activity is shorter and more related to night time.
The article discusses ways for optimization of a standard nozzle cup design to achieve a narrower paint flow. The analysis of a standard nozzle cup shows that distribution of air pressure is ...critically uneven both along the nozzle axis and in the radial direction. A decrease in pressure is about
% at the distance of
from the front surface of the nozzle cup. Air pressure decreases about
% at the distance of
from the nozzle axis in the radial direction. Air velocity decreases about
% at the distance of
from nozzle surface but then the velocity stabilizes and decreases is about
% at the distance of
from the nozzle surface in comparison to its magnitude on the nozzle surface.
Six extra holes and a circular rim were added to the standard nozzle cup to obtain paint stream as narrow as possible. Also was modified inner surface of the nuzzle cup. Totally, four different components were analysed. The results show that with increasing the nozzle cone by fifteen or more degrees, the pressure distribution decreases. Most optimal solution has six small holes around the nozzle hole and a small rim covering all holes. In this case, pressure decreases only
% in the axial direction and
% in the radial direction at the distance of
from the front surface of the nozzle. Distribution of air velocity is still significant but its magnitude is about
% …
% less than at the standard nozzle cup.
Kinetic tensiometric dependences and isotherms of wetting leaves of the Prime potato were obtained for aqueous solutions and submicron dispersions of nonmicelle-forming surfactants (Tween 85, Brij ...L4, and Silwet L-77). A technique has been developed for determining the rate of penetration of the studied liquids into potato leaves. The penetration rate increases with increasing surfactant concentration. The permeability and wetting efficiency increase in the following row: Tween 85 < Brij L4 < Silwet L-77. The data obtained make it possible to evaluate the prospects for using the studied aqueous surfactant dispersions as platforms for the delivery of biologically active components into the leaves of potato plants to inhibit the reproduction of pathogens.
The article discusses lift force generated by mini UAVs (Unmanned Aerial Vehicles). CFD (Computational Fluid Dynamics) simulations were made on the base of a 3D scanned propeller model. Influence of ...some geometrical parameters of propeller (like velocity or pitch) and quadcopter (like gap) on lifting force was considered. Different propeller pitches were used and pitch influence on propeller lift force was analysed. Normally, lifting force will increase with the increasing of propeller pitch but for different rotation velocities, this increasing is different and in all cases, it can be approximated by a linear relationship. To obtain dependency functions, an equation for calculation of lift force given took into account the correction coefficients. This equation gave reliable results at pitch values equal to 0.3 - 0.7 of the propeller diameter and at rotation velocities of 2000 min-1 - 8000 min-1. Lift force dependency from distance between rotors was also considered. Simulations and experiments showed that the lifting force of a quadcopter increased about 15% on gap distances from 5 mm to 35 mm. From a distance of 70 mm, the lifting force will decrease about 2% and then will stabilise. At increasing of distance between propellers from 5 mm until 25 mm, the power consumption decreased 8% - 10% and after the gap distance equal to 40 mm, it will be stable and minimal. It can be asserted that quadcopters have different optimal distances between the propellers at different rotation speeds to generate the same force. Equations for calculation of optimal gap distances for different multicopters were derived and calculation results are presented in graphs and tables.
An extraordinary phenomenon of generation of coupled types of oscillations with a transverse field distribution corresponding to the ТЕМ
pq
eigenmodes with different pairs of indices
p
and
q
in the ...main laser cavity and in an external cavity has been experimentally detected. The excitation of coupled modes depends on the configuration and tuning of partial cavities. To solve the system of integral equations for a three-mirror cavity with mismatched spherical mirrors in the quasioptical approximation, it has been proposed to use modified boundary conditions including the coupling coefficients for eigenmodes in partial cavities.
This paper shows that successful switching of extremely high short-circuit currents I> 50 kA can be achieved by joint operation of a liquid-metal self-resetting current limiter and a circuit breaker ...connected in series. The type NFU-225 device from Mitsubishi was taken as an example. The time-current characteristic of joint operation of a liquid-metal self-resetting current-limiting device and a circuit breaker was compiled. However, further in the article physical processes occurring in a liquid-metal self-resetting current limiter with a complete transformation of fusible unit are considered. The result of work is modelling of operation of liquid-metal fuses when overcurrents are switched off based on the pilot studies obtained by the Japanese scientists. It is proposed to simulate the break process not at every time moment, but at specific time moments (reference points). At other time moments, current and voltage should be considered as approximately linearly changing characteristics. The work of current limiter can be represented by three stages: the pre-arc, the main arc and the final arc. If the current density is less than 1000 A/mm2, then the pre-arc operation stage of the current limiter includes the following sections for heating the fusible unit: primary heating to the melting temperature; melting and its transition to liquid state; secondary heating to evaporation temperature; evaporation of fusible unit.
Population demography parameters of common small mammals have been obtained using two different census methods and intercompared. Resident population density and nonresident activity parameters were ...obtained on live-trap lines using the capture–mark–recapture method. Abundance parameters were obtained on break-back trap lines using the permanent removal (PR) method. Censuses performed using the PR method reflect the population dynamics of small mammals in general, but they may misrepresent the species ratio in the community. Multiple regression analysis shows that results obtained using the PR method are significantly affected both by the resident population density and nonresident activity of the species. Together, these factors explain 88.8% of the variance, while their individual contributions assessed on the basis of semipartial correlations in the multiple correlation model are as follows:
r
= 0.39 (resident population) and
r
= 0.46 (nonresident activities).
The synthesis of a new series of 1-ω-(bromophenoxy)alkyl-uracil derivatives containing in position 3 naphthalen-1-yl-, naphthalen-2-yl-, 1-bromonaphthalen-2-ylmethyl, benzyl, and anthracene 9-methyl ...fragment was carried out. The antiviral properties of the synthesized compounds were studied against human cytomegalovirus. It was found that the compound that contained a bridge of five methylene groups has a high anti-cytomegalovirus activity in vitro.
It has been found that the total productivity of bacteria and micromycetes in the 0- to 50-cm layer of homogeneous cryozems (Cryosols) on slopes of northern and southern exposures varies from 1.2 to ...1.4 t/ha, respectively, and the calculated content of microbial carbon varies in the range 0.7–0.9 t/ha. The respiratory activity of the upper soil layer is 2.5–2.6 μg C–CO
2
/(g h); the potential methane formation capacity reaches 0.13 nmol CH
4
/(m
2
day) for soils on slopes of northern exposure and 0.16 nmol CH
4
/(m
2
day) for slopes of southern exposure. Accumulation of sorbed ammonium is recorded in the range 15–17 mg NH
4
/100 g soil in summer. The increase of temperature in the upper horizons of soils on slopes of southern exposure by 5°C compared to the northern slopes results in only an insignificant increase in the emission of CO
2
and CH
4
. The accumulation of sorbed ammonium and nitrate nitrogen in homogeneous cryozems during the vegetation period is comparable to that in gray forest soils of the southern taiga subzone of the Middle Siberia.
NMR Studies of Porous Media: Specific Features Aleksandrov, D. A.; Voronov, A. A.; Maksimychev, A. V. ...
Physics of particles and nuclei letters,
09/2021, Letnik:
18, Številka:
5
Journal Article
Recenzirano
A model water-filled porous medium is investigated using NMR techniques, and the results of these measurements are interpreted theoretically. A rigorous theoretical description of the near-surface ...layer, qualitatively introduced when interpreting the NMR data for porous materials, is formulated. Our results indicate that the thickness of the near-surface layer exceeds that quoted in the literature by several orders of magnitude. This result allows to obtain valuable information about the processes at the liquid-solid interface.
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