The method for rapid assessment of vehicle stability in traction mode

One of the important operational properties of a car that ensures traffic safety is the stability of the car. The loss of stability of the car is a negative phenomenon leading to the occurrence of road accidents. Currently, a number of electronic systems are used to eliminate the loss of stability of the car. But most of them are aimed at eliminating the loss of stability, and not at preventing this condition. Depending on the driving mode of the car (traction, free run), the stability of its movement is evaluated by various parameters. These parameters can be used to quickly assess the stability of the vehicle, but this requires adequate techniques that take into account the main parameters of the car that affect its stability when driving, as well as traffic conditions. The currently existing methods and expressions for calculating the stability parameters of a car have a number of assumptions. This does not reduce their value, but somewhat reduces the accuracy. The purpose of this work was to increase the stability of the car by developing a method for quickly assessing its stability in traction mode. In theoretical studies, it was found that the stability coefficient can be used to assess the stability of a car with all-wheel or rear-wheel drive. It is equal to the ratio of the stabilizing moment of the car to the perturbing one. If this coefficient is greater than one, the car will be stable. The expression for its calculation includes a number of design and operational parameters of the vehicle. Expressing from it the acceleration values corresponding to the values of the stability coefficient greater than one, we get the maximum permissible accelerations that ensure stable movement of the car. Based on this, a method of operational assessment of the stability of the car was proposed, which consists in comparing the maximum permissible accelerations of the car with the actual ones. To improve the accuracy of calculations of the maximum permissible accelerations, it is proposed to determine the height of the center of mass of the car depending on its actual mass using linear interpolation. The scientific novelty of this work is the proposed method of operational assessment of the stability of the car, based on a refined methodology for calculating the maximum permissible accelerations. To calculate the values of the maximum allowable accelerations according to the proposed method, a computer program was developed. The direction of further research is to assess the adequacy of the proposed method by conducting experimental studies

Refined method for calculating heading angles of a vehicle at the end of braking

Reducing the number of road accidents is an urgent task, the solution of which can be achieved, including by improving the design of vehicles. One of the most common causes of road accidents is the occurrence of a car skidding during braking with its subsequent exit from the traffic corridor. The effective development of new vehicle safety systems that increase its directional stability during braking and the improvement of existing systems is possible only if there are reliable methods that take into account the main parameters of the vehicle that affect its stability during braking. The currently existing methods and expressions for calculating the heading angles of a car at the end of braking have a number of assumptions that facilitate the calculations. This does not diminish their value, but slightly reduces accuracy. The purpose of this work was to clarify the methodology for calculating the permissible and actual heading angles of the vehicle at the end of braking. Within the framework of the work, theoretical studies have been carried out, based on the analysis of existing research on this topic. Based on the analysis performed, it was found that the existing methods and expressions for calculating the heading angle of a car at the end of braking do not take into account the effect of differences in the track dimensions of the front and rear axles of the car, and the center of mass of the car is conventionally assumed to be located on the longitudinal axis of the car. Evaluation of the influence of these parameters on the accuracy of calculations has not been carried out at present, there are no expressions for calculating the permissible heading angle of the vehicle at the end of braking. As a result of theoretical studies, a refined technique was obtained, including expressions for calculating the actual heading angle of the vehicle at the end of braking under various braking modes. The previously specified parameters are taken into account in the expressions obtained. An equation was derived to calculate the permissible heading angle of the car at the end of braking, taking into account the dimensions of the car, its location relative to the edge of the carriageway and the width of the lane. The refined expressions and the resulting equation that form the methodology for calculating the heading angles of the vehicle at the end of braking represent the scientific novelty of this work. To increase the efficiency of calculations according to the proposed method, a computer program has been developed. The direction of further research is to assess the adequacy and accuracy of the proposed methodology using the developed program

Treatment of petroleum-contaminated water resources: modern techniques

The article deals with the issue of petroleum-contaminated water resources. The authors have analyzed the dynamics of oil spills, including the world's largest ones, and claimed the issue to be global. The modern methods of mitigating oil spill effects have been studied, as well as the modern techniques of water resource treatment. The particular attention is paid to peat sorbent production, which is considered a promising trend of petroleum- contaminated water treatment

Observation of Crossover from Ballistic to Diffusion Regime for Excimer Molecules in Superfluid 4^4He

We have measured the temperature dependence of the time of flight of helium excimer molecules He2* in superfluid 4He and find that the molecules behave ballistically below 100mK and exhibit Brownian motion above 200 mK. In the intermediate temperature range the transport cannot be described by either of the models.Comment: 8 pages, 6 figures, submitted to the Proceedings of the International Conference on Quantum Fluids and Solids 201

First test of an enriched 116^{116}CdWO4_4 scintillating bolometer for neutrinoless double-beta-decay searches

For the first time, a cadmium tungstate crystal scintillator enriched in $^{116}$Cd has been succesfully tested as a scintillating bolometer. The measurement was performed above ground at a temperature of 18 mK. The crystal mass was 34.5 g and the enrichment level ~82 %. Despite a substantial pile-up effect due to above-ground operation, the detector demonstrated a high energy resolution (2-7 keV FWHM in 0.2-2.6 MeV $\gamma$ energy range), a powerful particle identification capability and a high level of internal radiopurity. These results prove that cadmium tungstate is an extremely promising detector material for a next-generation neutrinoless double-beta decay bolometric experiment, like that proposed in the CUPID project (CUORE Upgrade with Particle IDentification)

The nature of lithium perchlorate and gallium chloride salt effect in cycloaddition reactions

Comparing the acceleration effects of (4 + 2)-, (3 + 2)- and (2 + 2)-cycloaddition reactions in the presence of the salts of two types: gallium chloride in inert solvents and lithium perchlorate (LP) in diethyl ether (DE) it was observed that in the presence of GaCl3 the acceleration effect is approximately the same (104 times) for the studied reactions, while in LPDE medium for the same reactions strong increase (up to 104 times), weak increase or even decrease of the rate and equilibrium constants take place even with the common dienophile depending on the nature of the second reagent. it was suggested that the acceleration effect of cycloaddition reactions in the presence of such Lewis acids as aluminum, gallium or boron halides is due to the sharp increase of Π-acceptor properties of dienophiles and therefore increasing energy of orbital interaction, whereas LPDE medium demonstrates strong stabilization of static and/or dynamic polar forms and favors reactions with charge control

Cycloheptatriene in the reaction of ene synthesis with diethylazodicarboxylate

© 2015 Pleiades Publishing, Ltd. The rate of an ene reaction between cycloheptatriene and trans-diethylazodicarboxylate in 1,2-dichloroethane was studied at various pressures and temperatures. The results obtained were compared with kinetic parameters of some other reactions

Применение корреляционного метода определения скорости потока теплоносителя при исследованиях гидродинамики турбулентных потоков в элементах ядерных реакторов

The method of correlation measurement of the coolant flow rate, widely used for operational diagnostics of nuclear power plants, can be extensively used in research practice. The aim of this work was to apply a correlation method based on the conductometric measurement system with wire-mesh sensors for measuring a coolant flow rate. Insignificant concentration of a salt solution (NaCl or Na2SO4 ) creates a gradient of the conductivity in the flow, which is used as a passive scalar measured by the system. Authors used turbulent pulsations at the interface of two concurrent flows with identical velocities in a square channel as a signal source for the correlation method. The paper presents the methodology of the tests, test facility description, signalto- noise ratio estimation, the results of digital signal processing and comparison of the measured velocities in the model with the flowrate‒averaged velocity determined by the use of flowmeters. The measured velocity values give acceptable agreement for the turbulent flow modes. It was shown that the measurement accuracy drops sharply for low-Reynolds flows. The obtained results were used for flowrate measurements in core-imitator channels of the nuclear reactor test model. The presented paper is an approbation of this approach for its application as part of an test model of a nuclear reactor in order to determine the each duct flow rates in the channels of the core simulator using wire mesh sensors