Corrosion and mechanical testings of tube steel for forecasting of life of oil pipelines

The paper shows the results of experimental studies of corrosion and mechanical and corrosion characteristics of pipe steels of the pipelines in corrosive medium models, graphic dependences are constructed for the analysis of corrosion and mechanical processes

Can hydrodynamic contact line paradox be solved by evaporation--condensation?

We investigate a possibility to regularize the hydrodynamic contact line singularity in the configuration of partial wetting (liquid wedge on a solid substrate) via evaporation-condensation, when an inert gas is present in the atmosphere above the liquid. The no-slip condition is imposed at the solid-liquid interface and the system is assumed to be isothermal. The mass exchange dynamics is controlled by vapor diffusion in the inert gas and interfacial kinetic resistance. The coupling between the liquid meniscus curvature and mass exchange is provided by the Kelvin effect. The atmosphere is saturated and the substrate moves at a steady velocity with respect to the liquid wedge. A multi-scale analysis is performed. The liquid dynamics description in the phase-change-controlled microregion and visco-capillary intermediate region is based on the lubrication equations. The vapor diffusion is considered in the gas phase. It is shown that from the mathematical point of view, the phase exchange relieves the contact line singularity. The liquid mass is conserved: evaporation existing on a part of the meniscus and condensation occurring over another part compensate exactly each other. However, numerical estimations carried out for three common fluids (ethanol, water and glycerol) at the ambient conditions show that the characteristic length scales are tiny

Quench cooling under reduced gravity

We report the quench cooling experiments performed with liquid O2 under different levels of gravity simulated with the magnetic gravity compensation. A copper disk is quenched from 270K to 90K. It is found that the cooling time in microgravity is very long in comparison with any other gravity level. This phenomenon is explained by the isolation effect of the gas surrounding the disk. The liquid subcooling is shown to drastically improuve the heat exchange thus reducing the cooling time (about 20 times). The effect of subcooling on the heat transfer is analyzed at different gravity levels. It is shown that such type of experiments cannot be used for the analysis of the critical heat flux (CHF) of the boiling crisis. The minimum heat flux (MHF) of boiling is analyzed instead

Droplet evaporation in one-component fluids: Dynamic van der Waals theory

In a one-component fluid, we investigate evaporation of a small axysymmetric liquid droplet in the partial wetting condition on a heated wall at $T\sim 0.9 T_c$. In the dynamic van der Waals theory (Phys. Rev. E {\bf 75}, 036304 (2007)), we take into account the latent heat transport from liquid to gas upon evaporation. Along the gas-liquid interface, the temperature is nearly equal to the equilibrium coexisting temperature away from the substrate, but it rises sharply to the wall temperature close to the substrate. On an isothermal substrate, evaporation takes place mostly on a narrow interface region near the contact line in a late stage, which is a characteristic feature in one-component fluids.Comment: 6 pages, 6 figure

Experimental analysis and transient numerical simulation of a large diameter pulsating heat pipe in microgravity conditions

A multi-parametric transient numerical simulation of the start-up of a large diameter Pulsating Heat Pipe (PHP) specially designed for future experiments on the International Space Station (ISS) are compared to the results obtained during a parabolic flight campaign supported by the European Space Agency. Since the channel diameter is larger than the capillary limit in normal gravity, such a device behaves as a loop thermosyphon on ground and as a PHP in weightless conditions; therefore, the microgravity environment is mandatory for pulsating mode. Because of a short duration of microgravity during a parabolic flight, the data concerns only the transient start-up behavior of the device. One of the most comprehensive models in the literature, namely the in-house 1-D transient code CASCO (French acronym for Code Avancé de Simulation du Caloduc Oscillant: Advanced PHP Simulation Code in English), has been configured in terms of geometry, topology, material properties and thermal boundary conditions to model the experimental device. The comparison between numerical and experimental results is performed simultaneously on the temporal evolution of multiple parameters: tube wall temperature, pressure and, wherever possible, velocity of liquid plugs, their length and temperature distribution within them. The simulation results agree with the experiment for different input powers. Temperatures are predicted with a maximum deviation of 7%. Pressure variation trend is qualitatively captured as well as the liquid plug velocity, length and temperature distribution. The model also shows the ability of capturing the instant when the fluid pressure begins to oscillate after the heat load is supplied, which is a fundamental information for the correct design of the engineering model that will be tested on the ISS. We also reveal the existence of strong liquid temperature gradients near the ends of liquid plugs both experimentally and by simulation. Finally, a theoretical prediction of the stable functioning of a large diameter PHP in microgravity is given. Results show that the system provided with an input power of 185W should be able to reach the steady state after 1min and maintain a stable operation from then on

РИСК-МЕНЕДЖМЕНТ – ИНСТРУМЕНТ ОБЕСПЕЧЕНИЯ БЕЗОПАСНОСТИ ПЕРЕВОЗОК В РОССИИ

Safety of transportation in Russia is subject to a variety of threats. Discussed in the article are characteristics of major threats to transportation security. State transportation policy directions that make it possible to ensure the security of cargo and passenger transportation are shown. A listof activities and innovative risk management tools that provide for improved safety of railway transportation is proposed.Безопасность перевозок в России подвергается целому ряду угроз. Рассматриваются краткие характеристики основных угроз безопасности перевозок. Показаны направления государственной транспортной политики, позволяющей обеспечить безопасностьгрузовых и пассажирских перевозок. Предложен перечень инновационных мероприятий и инструменты риск-менеджмента, обеспечивающие повышение уровня безопасности на железнодорожном транспорте

Здравоохранение Якутии в 1930—1940 гг.: обеспечение кадрами

Historical data of provision with personnel of public health service in Yakutia within 1930—1940 have been introduced. Arrival of experts from central and Siberian regions of Russia was of great significance of that period.Представлены исторические сведения о кадровом обеспечении здравоохранения Якутии в 1930-1940 гг., которое происходило в основном за счет специалистов, прибывающих из центральных и сибирских областей России

Quantitative assessment of adherence to treatment in clinical medicine: protocol, procedure, interpretation

We developed and embedded in research and clinical practice of the method of quantitative evaluation of adherence to treatment in clinical medicine. Assessment of adherence is investigated by completion of the questionnaire. Analysis of the answers allows us to quantitatively calculate the indicators of adherence to drug therapy, medical support, modification of lifestyle and integral adherence to treatment. In accordance with the obtained results, an adherence can be «high,» «satisfactory» or «unsatisfactory», serving as a basis for making research or treatment decisions. Dynamic quantitative assessment of adherence allows to assess the current efficacy of interventions and to forecast their trends. The questionnaire is recommended for use in clinical practice when treating patients with chronic diseases, as well as at the stages of organization and execution of clinical studies and clinical trials

A Miniature Non-Uniform Conformal Antenna Array Using Fast Synthesis for Wide-Scan UAV Application

To overcome the limited payload of lightweight vehicles such as unmanned aerial vehicle (UAV) and the aerodynamic constraints on the onboard radar, a compact nonuniform conformal array is proposed in order to achieve a wide beamscanning range and to reduce the sidelobes of the planar array. The non-uniform array consists of 7x4 elements where the inner two rows follow a geometric sequence while the outer two rows follow an arithmetic sequence along the x axis. The element spacing along the y axis is gradient from the center as well. This geometry not only provides more degrees of freedom to optimize the array radiation, but also reduces the computation cost when synthesizing the excitation and the configuration of the array for a specific beam pattern. As field cancellation may happen due to the convex and concave features of the non-canonical UAV surface, a fast and low-cost in-house code to calculate the radiation pattern of a large scale conformal array for an arbitrary surface and element pattern is employed to optimize the array structure. As a proof of concept, the proposed array with a total volume of 142x93x40 mm3 is implemented at ISM band (5.8 GHz) using a miniature widebeam single-layer patch antenna with a dimension of 0.12lambdax0.12lambdax0.025lambda. By using the beamforming technique, an active onboard system is measured, which achieves the maximum gain of 21.8 dBi and a scanning range of >50deg and -28deg~28deg with a small scan loss of 2.2 and 0.5 dB in elevation and azimuth, respectively. Therefore, our design has high potential for wireless communication and sensing on UAV.Comment: 11 pages,14 figure