483 research outputs found
Numerical simulation of high-current ion beam acceleration and charge compensation in magnet-isolated systems
Погребённые и внутригрунтовые пластовые льды на западном побережье Байдарацкой губы Карского моря
Using data on the structure, conditions of occurrence (bedding), and the isotope composition of massive ice beds on the West coast of Baydaratskaya Bay it was established that the massive ice beds even occurring in the same outcrop may be related to different genetic types. There are two groups of the massive ice: 1) the «upper» thick (> 3 m) massive ice beds composed by buried basal glacier ice; and 2) the «lower» small ice beds (< 3 m), formed both intrasedimentally and as a result of burial of initially surface ice bodies. Sand thickness which included both groups of the massive ice started its formation before the glacial ice burial. As a result of advancing and later degradation of the glacier, probably moving from the Pay-Khoy ridge or from the Polar Ural, its lower (basal) parts were preserved within the permafrost thickness. На основе данных о строении, условиях залегания и изотопном составе пластовых льдов на западном побережье Байдарацкой губы установлено, что даже залегающие в одном разрезе пластовые залежи могут относиться к разным генетическим типам. Выделены две группы пластовых льдов: 1) мощные (> 3 м) залежи погребённого базального ледникового льда; 2) небольшие залежи (< 3 м), сформировавшиеся как внутри грунта, так и при погребении небольших первично-поверхностных ледяных тел. Песчаная толща, вмещающая пластовые льды обеих групп, начала формироваться до захоронения ледникового льда. В результате наступания и последующей деградации ледника, спускавшегося, вероятно, с хр. Пай-Хой или с Полярного Урала, его нижние части были законсервированы в мёрзлой толще.
Analysis of model for assessing the road train movement stability
In this paper, we conduct a mathematical analysis of the model of ensuring the road trains movement stability by changing the design of coupling devices to determine the critical characteristic parameters of the road trains, which result in the loss of en-route directional stability under external action. The concept of the model was to separate the process of yawing of the road trains and its elements (due to external perturbing action) on the highway into several typical stages. The main parameters of the stages (the displacement amplitude and rotation angle of the road trains elements in relation to the driving direction) were determined based on the initial conditions of the road trains movement, the force and duration of the external action. The most dangerous areas of external action application to the road trains were determined in this paper. The maximum permissible exposure limit should not exceed 0.5-1.0% of the road trains trailer momentum, with duration having the greater effect than the amount of impact. The results obtained can be used in mechanical engineering to improve the road trains performance. © Published under licence by IOP Publishing Ltd
Model for assessing the road train stability movement
Road trains (RT) are the main transport in agriculture. However, their accident rate is quite high. In the vehicles movement research their design characteristics and operating modes are mainly improved. The main way to reduce the accident rate remains the speed limit. The authors proposed methods (confirmed by the issued patents) for ensuring the stability of the RT movement by changing the design of trailer devices. The purpose of this work is to form a mathematical model for assessing the stability of the RT movement in the presence of side effects (modeling of sharp turns, impacts). Methods of analysis and synthesis, mathematical analysis, and vector geometry were applied. The process of RT yawing on the highway is split into a number of stages, for which the laws of changing its geometry and kinematics are formulated. Side effect leads to increase in the RT impulse (lateral oscillations increase the speed), or to a violation of stability (the movement amplitude goes beyond the highway or tipping). This model can be used to analyze the stability of the RT movement and evaluate methods to influence it in order to reduce the probability of accidents. © 2020 Published under licence by IOP Publishing Ltd
Identifying gravity waves launched by the Hunga Tonga-Hunga Ha‘apai volcanic eruption in mesosphere/lower thermosphere winds derived from CONDOR and the Nordic Meteor Radar Cluster
The Hunga Tonga-Hunga Ha‘apai volcano eruption was a unique event that caused many atmospheric phenomena around the globe. In this study, we investigate the atmospheric gravity waves in the mesosphere/lower thermosphere (MLT) launched by the volcanic explosion in the Pacific leveraging multistatic meteor radar observations from the Chilean Observation Network De Meteor Radars (CONDOR) and the Nordic Meteor Radar Cluster in Fennoscandia. MLT winds are computed using a recently developed 3DVAR+DIV algorithm. We found an eastward and a westward traveling gravity wave in the CONDOR zonal and meridional wind measurements, which arrived 12 hours and 48 hours after the eruption, and one in Nordic Meteor Radar Cluster that arrived 27.5 hours after the volcanic detonation. We obtained observed phase speeds for the eastward great circle path at both locations of about 250 m/s and 170–150 m/s for the opposite propagation direction. The intrinsic phase speed was estimated to be 200–212 m/s. Furthermore, we identified a potential lamb wave signature in the MLT winds using 5 minute resolved 3DVAR+DIV retrievals
Metal-semiconductor (semimetal) superlattices on a graphite sheet with vacancies
It has been found that periodically closely spaced vacancies on a graphite
sheet cause a significant rearrange-ment of its electronic spectrum: metallic
waveguides with a high density of states near the Fermi level are formed along
the vacancy lines. In the direction perpendicular to these lines, the spectrum
exhibits a semimetal or semiconductor character with a gap where a vacancy
miniband is degenerated into impurity levels.Comment: 4 pages, 3 figure
Development and Testing of Monoclonal Antibodies-Based Diagnostic Preparation for <i>Bacillus anthracis</i> Spores Detection Using Latex Agglutination Method
Immobilization of anti-B. anthracis monoclonal antibodies (MAbs) on latex microparticles was studied, the optimal load of these MAbs was determined to be 20 µg for 50 µl of the stock latex suspension. The highest sensitivity of latex agglutination test was observed for 1E6 MAbs. Latex suspensions with immobilized MAbs were lyophilized. Their sensitivity and specificity were shown to be highly competitive with those of the stock liquid latex suspension. Latex diagnosticum for Bacillus anthracis spores detection was constructed on the basis of these lyophilized reagents, developed and approved was the regulatory documentation that included their application instructions and technical specifications. Carried out were inter-laboratory and commission tests of experimental prototypes of the designed latex diagnosticum. These preparations demonstrated high sensitivity (from 1·105 to 2·106 spores/ml and even more) and specificity (absence of cross-reactions with spores of different species of sporogenous bacilli at concentration of 108 spores/ml)
Comparative analysis of photometric variability of TT ARI in the years 1994-1995 and 2001, 2004
We present the results of photometric observations of a bright cataclysmic variable TT Ari with an orbital period of 0. 13755 days. CCD observations were carried out with the Russian-Turkish RTT 150 telescope in 2001 and 2004 (13 nights). Multi-color photoelectric observations of the system were obtained with the Zeiss 600 telescope of SAO RAS in 1994-1995 (6 nights). In 1994-1995, the photometric period of the system was smaller than the orbital one (0. d132 and 0. d134), whereas it exceeded the latter (0. d150 and 0. d148) in 2001, 2004. An additional period exceeding the orbital one (0. d144) is detected in 1995 modulations. We interpret it as indicating the elliptic disc precession in the direction of the orbital motion. In 1994, the variability in colors shows periods close to the orbital one (0. d136, b-v), as well as to the period indicating the elliptic disk precession (0. d146, w-b). We confirm that during the epochs characterized by photometric periods shorter than the orbital one, the quasi-periodic variability of TT Ari at time scales about 20 min is stronger than during epochs with long photometric periods. In general, the variability of the system can be described as a "red" noise with increased amplitudes of modulations at characteristic time scales of 10-40 min. © 2013 Pleiades Publishing, Ltd
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