The paper considers thermodynamics as a measurement of extensive variables, such as energy, volume and mass. In this sense, thermodynamic states are Legendrian or Lagrangian surfaces in the ...corresponding contact or symplectic space. The Beattie–Bridgeman model was chosen to describe phase transitions and their features for the equation of state of a real gas. This model describes the state of a substance in two phases: liquid and vapor. Real gas can be either single gase or a mixture. Formulas for calculating model constants for any mixture of gases are obtained. The caloric equation of state and various potentials are derived. The phase transition for a mixture of alkanes from oil production is constructed. Three critical phenomena for the phase transition of such a mixture are found. The Lagrangian manifold is constructed.
A comprehensive study of nitrogen doped carbon nanotubes (N–CNTs) with nitrogen content varying from 0 at.% to 7.3 at.% is reported. A correlation is revealed between the content of pyridine-like ...nitrogen and the defectivity of the N–CNT bamboo-like structure. A model of graphene layer with defects containing ordered carbon vacancies and pyridine nitrogen is proposed. The model is based on a combination of experimental data obtained by powder X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy, scanning electron microscopy and simulation of the N–CNT structure by the use of g-C
3
N
4
structural elements. It is shown that more than a two-fold increase of the N–CNT specific capacity in acidic and alkaline electrolytes compared to that of undoped carbon nanotubes is due to the fact that N–CNTs posses significantly better hydrophilic properties due to the defects based on pyridine-like nitrogen centers. The N–CNT efficiency as a catalyst and a palladium catalyst support in the reaction of oxidative desulfurization of dibenzothiophene is demonstrated.
A brief analysis of the existing technical solutions for the purification of gases from hydrogen sulfide is carried out. The huge volume of such emissions and the lack of ready-made solutions for ...mini-gas processing plants and mini-refineries determine the relevance of the development of environmentally reliable, efficient and compact technologies to solve this problem. The main results of tests of technologies and installations developed at the Institute of Catalysis of the Siberian Branch of the Russian Academy of Sciences (Novosibirsk) based on the direct catalytic oxidation of hydrogen sulfide are presented.
In test research, the technology of the blades growing on the disk part of the titanium compressor wheel by heterophase laser powder metallurgy was applied. The experiments were carried out to select ...the optimal modes of the process, ensuring the absence of defects in the form of pores, non-melting, cracks. The influence of granulometric composition on mechanical characteristics was also investigated. The optimal modes of the additive technological process, providing the formation of a defect-free structure and optimal mechanical properties of the blanks are found as a result of the experiments. The samples of titanium powder alloy Ti6Al4V and hybrid samples consisting of cast and powder materials were produced with the help of technology mention above. Tests of the grown and hybrid samples were carried out to determine the mechanical properties. Studies of micro and macrostructure of the samples were produced. Calculations of the stress-strain state and dynamic characteristics for the initial and hybrid glare using the found mechanical properties were carried out. Preparing testing hybrid titanium wheel carries out now. This technology also can be used for repairs of blisks blades.
This paper considers how modeling conditions affect the accuracy of the on-chip spiral inductor. Various approximation methods, such as Kriging model for interpolation by exponential correlation and ...single exponential correlation functions, radial basis function, and inverse distance weighting, are considered. Several types of response are investigated, including
S
-parameters,
Y
-parameters,
Y
11
response, inductance, and
Q
-factor. Surrogate modeling combines the Kriging model for interpolation and adapting space mapping. Electromagnetic simulation results are used as the fine model, while the compact model is used as the crude model. The surrogate model is created to design the parameter space, which provides the inductance of 0.9 to 31.9 nH at a 1 GHz step. As a result, the best conditions are identified for surrogate modeling of the on-chip spiral inductor providing
S
-parameter and phase relative errors of 3.29 and 3.03%, respectively.
An algorithm for studying the change in the technical condition of pipelines made of fiberglass with a diameter of 75 and 130 mm during operation and the accumulation of damage in the pipe wall by ...the vibroacoustic method is considered. The effect of dynamic loading and damage accumulation (microcracks and their development) were evaluated on the basis of the change in the magnitude of the amplitude–frequency shift before and after a certain test cycle. The boundaries of the change in performance in the amplitude–frequency region for pipes made of polymer-composite materials have been established.
This article presents the results of deep seismic studies over the Sikhote-Alin fragment of the 8-DV reference geophysical profile running across the large fold structures of the Pacific tectonic ...belt, that is, the Sikhote-Alin Orogenic Belt with the superimposed Middle Amur sedimentary basin and the East Sikhote-Alin volcanoplutonic belt. A deep seismic section of the Earth’s crust and upper mantle with the distribution of longitudinal wave velocities is constructed. In the upper part of the section, P-wave velocities vary from 4.0–5.0 km/s within the Middle Amur sedimentary basin and the eastern part of the Eastern Sikhote-Alin volcanoplutonic belt to 5.5–5.6 km/s in the central part of the Sikhote-Alin Orogenic Belt. It was established that the thick Paleozoic sedimentary complex within the Middle Amur sedimentary basin is faulted and folded in a complex manner. Crystalline rocks with a compressional wave velocity of 6.0–6.2 km/s occur at depths from 8 to13 km in different parts of the Middle Amur sedimentary basin and at depths of 4–6 km within the Sikhote-Alin orogenic complex. Compressional wave velocities of the crust in the Sikhote-Alin fragment of the 8-DV profile are between 6.3 and 6.35 km/s. The crust varies in thickness from 32–34 km in the northern part of the fragment to 36–37 km in its central and eastern parts. Along the Moho, P-wave velocities are 8.1–8.3 km/s; a number of areas with reduced
V
p
of 7.8 to 8.0 km/s were identified in the junction zones of large crustal blocks.
P
-wave data were used to identify anomalies which were correlated with structural-tectonic zones, deep fault zones, and seismicity. The thick Middle Amur sedimentary basin was distinguished along the Central Sikhote-Alin deep fault. This basin is filled by Paleozoic low-velocity deposits and is displaced along the fault plane by 4–5 km at its junction with the Sikhote-Alin Orogenic Belt. Zones of increased heterogeneity in the upper crust projected onto the area within the contours of the Middle Amur sedimentary basin are characterized by increased seismicity.
Abstract
This article describes in detail the process of creating panels from a composite material by the method of vacuum infusion with various types of defects pre-installed in them. The most ...common types of defects that can arise in parts made of composite materials as a result of a violation of the technological process, the presence of defects in the original material, in particular, reinforcing fabric, as well as defects associated with the low qualification of the master are considered. The creation of such prototypes is necessary for the development of quality control methods for products made of composite materials. A vibroacoustic diagnostic method based on the passage of acoustic waves through a composite product is considered. It is shown that it is possible to estimate the size of a defect and the depth of its occurrence in a composite material by changing the intrinsic frequency characteristics of the wave field. Experimental data on diagnosing panels with defects is presented.
Peripheral arterial blood flow during the exposure to head-to-legs g-loads (+Gz) on a short-arm centrifuge (SAC) has been investigated. The purpose was to use some objective monitoring instruments ...for testing the hypothesis that the hemodynamic reaction to +Gz would be analogous to the reactions observed in the tilt test and/or the lower body negative pressure (LBNP) test. Six normal male subjects participated in 6 SAC runs with alternating interval g-loads of +1.27 and +2.7 Gz. Blood flow in the femoral (FA) and middle cerebral (MCA) arteries was recorded continuously before, during and after the runs by Doppler flowmetry (CARDIOMED device). It was found that +Gz centrifugation produced typical anti-gravity changes in hemodynamics, i.e., an increase in FA resistance and a decrease in MCR resistance. In comparison to the records at rest, the FA blood flow decreased by 60%; the MCA blood flow changed insignificantly: by no more than –10%. It was confirmed that +Gz centrifugation has the same effects as the Earth’s gravity in standing humans, produces orthostatic blood pressure in the lower part of the body, and initiates the totality of anti-gravity hemodynamic reactions. Doppler recording was a quite useful source of data about the blood flow reaction to +Gz centrifugation.
The basics of load tests for a computer cluster with a large number of GPUs (graphics processing units) distributed over the cluster’s nodes are presented and implemented as a program code. ...Information about the time delays in the transfer of data of different sizes among all GPUs in the system is collected as a result. Two modes of tests, ‘‘all to all’’ and ‘‘one to one,’’ are developed. In the first mode, all GPUs transfer data to all GPUs simultaneously. In the second mode, only the transfer between two GPUs proceeds at a single moment in time. Using test results obtained on the K60 computer cluster at the Keldysh Institute of Applied Mathematics, Russian Academy of Sciences, it is shown that the interconnector medium of the supercomputer is inhomogeneous in data transfer among the GPUs not only for transfer through the network, but also for the GPUs in a common node of the computer cluster.
PDF
