Volume 97, №6


PHYSICS OF ISOTOPE SEPARATION IN SUPERSTRONG CENTRIFUGAL FIELDS: ACHIEVEMENTS AND UNRESOLVED PROBLEMS

A review of the results obtained by a group of researchers from National Research Nuclear University MEPhI in the course of computer simulation of the gas dynamics and separation of isotopic mixtures in gas centrifuges with ultrafast rotor rotation is presented. The physics of the obtained regularities, as well as unsolved problems are discussed
Author:  S. V. Bogovalov, I. V. Tronin
Keywords:  : gas centrifuge, isotope separation, gas dynamics, computer simulation
Page:  1423

COMBINED PROCESSES OF SEPARATION OF ISOTOPES OF LIGHT ELEMENTS: HISTORY AND NEAR-TERM OUTLOOK

Variants of combined technologies for separating isotopes of light chemical elements, using both thermodynamically reversible and irreversible separation methods, are considered from a historical point of view. The main criteria for assessing the effi ciency of combining diff erent isotope separation processes are indicated. Based on the specifi ed criteria, a number of problems of obtaining highly enriched carbon-13 and boron-10 isotopes are analyzed.
Author:  A. V. Khoroshilov
Keywords:  isotopes of light chemical elements, separation of isotopes, rectifi cation, chemical isotope exchange, laser method, gas centrifugal method, combined technologies
Page:  1433

EFFICIENCIES OF A NONMIXING (IDEAL) CASCADE AND A MIXING CASCADE WITH SEPARATION COEFFICIENTS DEPENDENT ON THE PARAMETERS OF A CASCADE STAGE

A comparison of the effi ciencies of the optimum mixing and nonmixing (ideal) cascades comprising stages, the coeffi cients of separation of a mixture at which are dependent on their parameters, has been performed. It was established that an optimized mixing cascade can have a smaller number of centrifuges, as compared to that of a nonmixing cascade, the separation capacity of whose stages deviate from the optimum one by 1–10%. For an optimum mixing cascade, this deviation is smaller, which can be explained by that the requirement for the fulfi llment of the nonmixing condition at the joints of fl ows in such a cascade narrows the area of search for the parameters of the cascade and thus excludes more eff ective variants of solving the separation problem.
Author:  A. R. Mustafi n, A. Yu. Smirnov, G. A. Sulaberidze
Keywords:  isotope separation, binary mixture, uranium enrichment, gas centrifuge, separation cascade
Page:  1441

BARODIFFUSION MECHANISM OF SEPARATION OF AN ISOTOPIC GAS MIXTURE IN SUPERSTRONG CENTRIFUGAL FIELDS UNDER THE IMPACT OF AN ACOUSTIC WAVE

In the rotating gas in a superstrong centrifugal fi eld, new mechanisms of separation of a binary isotopic gas mixture that are absent from a quiescent gas appear under the impact of waves. In the present work, an analysis of these mechanisms has been made. The mechanism of separation associated with the gas barodiff usion due to the diff erences between the radial distributions of the perturbation of pressure in the wave and pressure in an unperturbed fi eld has been considered in detail. Dependences of the separation, by the barodiff usion mechanism, on the frequency and amplitude of the wave have been obtained.
Author:  S. V. Bogovalov, D. N. Dzhulya, I. V. Tronin
Keywords:  gas centrifuge, separation of isotopes, gas dynamics, computer simulation
Page:  1450

TREATMENT OF LARGE VOLUMES OF TRITIATED WATER BY PHYSICOCHEMICAL METHODS OF SEPARATION OF HYDROGEN ISOTOPES

An analysis is made of today′ status of the problem of management of tritiated water formed on various objects of the nuclear industry. The approach to cleaning fl ows of such water of tritium depends on its concentration in the water and on the content of another hydrogen isotope, i.e., deuterium, in it. Consideration is given to the use of diff erent physicochemical methods of separation of hydrogen isotopes for cleaning tritiated water with a high concentration of deuterium and its natural content. Since the detritiation of heavy-water fl ows at the present time has been implemented on a fairly large scale, and the problem of cleaning of light water of tritium is at the stage of discussion, a comparative computational assessment of the dimensions of separation facilities of light-water detritiation based on the technologies of distillation of water and chemical isotope exchange of hydrogen with water is carried out.
Author:  M. B. Rozenkevich,I. L. Rastunova
Keywords:  radioactive hydrogen isotope, detritiation of water, physicochemical methods, separation of isotopes, multistage facilities
Page:  1461

ANALYSIS OF CASCADES COMPOSED OF TWO TYPES OF SEPARATORS BASED ON THE SEGMENTED Q-CASCADE

It is possible that an isotope separation cascade uses two types of separators having diff erent separation factors. Arrangement of the separators in the cascade may aff ect its separation performance and, therefore, fi nding the appropriate arrangement is of interest in practice. Six arrangements are considered, four of which have the schemes of a single cascade with four segments, and two have the schemes of a double cascade with two segments on each cascade. Based on the segmented Q-cascade, diff erent separators are installed in diff erent segments. Taking the cascade relative total fl ow as the objective of optimization, analyses are performed on the relations of the relative total fl ow with separation factors and the ratio of the two separators. The results show that diff erent arrangements result in diff erent performances, which can be signifi cant. The double cascade scheme is the best.
Author:  Shi Zeng,Hangyu Dong
Keywords:  isotope separation, cascade, segmented Q-cascade, heterogeneous separator
Page:  1471

SUBSTANTIATION OF THE POSSIBILITY TO OBTAIN 177Lu ON THE AVERAGE FLUX RESEARCH REACTOR IRT-T

Consideration is given to the possibility of obtaining 177Lu radionuclide on the average fl ux research IRT-T nuclear reactor. The paper presents the results of simulating the neutron spectrum of the central channel CEC-1 of the IRT-T research reactor in the MCU program, calculations of the production of 177Lu from 176Yb2O3 in the CEC-1 neutron fi eld and the dose rate from diff erent radionuclides at a distance of 1 m and experiments on the production of 177Lu and its separation. The results of calculations and experiments are in agreement within an error of no more than 10% for 177Lu. The performed calculations and experiments have made it possible to carry out a preliminary assessment of the activity of 177Lu radionuclide, which can be obtained on the IRT-T research nuclear reactor, and also determine radiation protection required for working with radioactive ytterbium and lutetium.
Author:  I. A. Ushakov, V. V. Zukau, E. A. Nesterov, N. V. Smol′nikov, E. A. Shelikhova, E. S. Donyaeva
Keywords:  chromatography, lutetium, ytterbium, separation, nuclear reactor
Page:  1478

3D NUMERICAL SIMULATION OF THE DRIVER EFFECT OF A CURVED SCOOP ON THE FLOW FIELD IN A GAS CENTRIFUGE

In order to fi gure out the driver eff ect of a curved scoop on three-dimensional fl ow fi eld in a gas centrifuge (GC), a double-chamber GC was used as the research object. 3D Navier–Stokes equations were solved by the semidiscrete fi nite volume method with high precision. Numerical results show that there are a bow-shaped shock wave and a detached-body shock wave being generated around the scoop. After the shock wave enters the separation chamber, it moves along a spiral trajectory, which leads to the disturbance of physical variables. Compared with other positions in the rotor, the gas pressure close to the side wall undergoes a more obvious change. The signifi cant axial velocity disturbance is distributed close to the artifi cial inner boundary, but the main mass transfer of gas occurs near the side wall. The variation of angular integration of axial mass fl ux in radial direction indicates that there are 3 axial circulations in the separation chamber
Author:  Dongyang Huang, Dongjun Jiang
Keywords:  gas centrifuge, 3D fl ow fi eld, scoop, shock wave, spiral wave, disturbance
Page:  1488

EFFECTS OF THE EXPERIMENTAL CONDITIONS ON THE RECOVERY OF THE FUNCTION OF SIZE DISTRIBUTION OF PORES

The knowledge of information on the structure of nanoporous materials is key for understanding heat and mass transfer and catalysis processes and also for predicting the behavior of nanoporous materials for various applications. Assessing the infl uence of various factors on the process of fi lling a nanoporous material with a nonwetting liquid is an important moment for the development of domestic porometry and techniques for processing experimental results in recovering the function of size distribution of pores. This paper presents the results of investigations into the eff ects of various conditions of the experiment on the fi lling of hydrophobized (water-repellent) Fluka 100 C8 silica gel with a nonwetting liquid (distilled water, glycerin, and ethylene glycol). Based on experimental data, functions of size distribution of pores have been determined. It is shown that functions of distribution coincide within the error for all experiments in the case of using distilled water as a nonwetting liquid.
Author:  V. D. Asafova, S. A. Kulakov, S. A. Bortnikova, A. A. Belogorlov
Keywords:  nanoporous material, nonwetting liquid, liquid porometry (mercury porosimetry), function of size distribution of pores
Page:  1503

EFFECTS OF THE COMPOSITION OF A NONWETTING LIQUID ON THE KINETICS OF OUTFLOW FROM A NANOPOROUS MATERIAL

The paper presents the results of investigation into the eff ects of the composition of a nonwetting liquid (distilled water, physiological solution, and doxorubicin solution) on the kinetics of outfl ow from hydrophobized Fluka 100 C18 silica gel. A series of measurements was taken regarding the fi lling of and discharge from the investigated systems in the temperature range of 5 to 40o C with the waiting time between cycles 10–1000 s. Values were obtained for the fraction of the liquid that failed to fl ow out of a porous material as a function of time and temperature, and also the functions of pore size distribution were recovered for the retained liquid. A reduction was found in the fraction of the retained liquid with increase in temperature and the waiting time. It follows from the obtained results that the determination of the outfl ow kinetics for a doxorubicin solution with a concentration of up to 1 μM can be carried out without using a medicinal drug.
Author:  V. D. Asafova, S. A. Kulakov, S. A. Bortnikova, A. A. Belogorlov
Keywords:  nanoporous material, nonwetting liquid, mercury porosimetry, nonwetting liquid relaxation
Page:  1508

INFLUENCE OF THE CHARACTERISTICS OF A NANOPOROUS MATERIAL ON NONWETTING-LIQUID FLOW UNDER AN IMPULSE ACTION

The infl uence of the parameters of a nanoporous material (mass, pore size, surface modifi cation) on the character of response of the system "nanoporous material–nonwetting liquid" to an impulse (shock) action has been investigated. Series of experiments with Fluka 100 C18 (#60756-50G), Fluka 90 C18 (#60757-50G), and Fluka 100 C8 (#60755-50G) nanoporous materials and distilled water have been conducted at diff erent masses of the samples in the system and diff erent energies of the shock action. Energies expended in fi lling the samples under study with distilled water and in it fl owing out of them subsequently have been obtained and the maximum velocity of fl ow of distilled water in the samples′ nanopores have been computed. Based on the obtained dependences, the conclusions have been drawn on the infl uence of the parameters of the materials under study and the shock energy on the response of the system "nanoporous material–nonwetting liquid" to the external impulse action.
Author:  I. A. Khlistunova, A. A. Belogorlov
Keywords:  nonwetting liquid, nanoporous material, fl ow, impulse action
Page:  1514

RELAXATION OF A NONWETTING LIQUID DISPERSED IN A PARTIALLY FILLED NANOPOROUS MATERIAL

The authors have given results of experimental study of metastable states of a nonwetting liquid (distilled water) dispersed in the pore space of hydrophobizated silica gel Fluka 100 C18 under the conditions of partial fi lling. The results were obtained for 10 and 22o C with a varying degree of fi lling (11 to 100%) at expectation times from 1 to 1000 s. According to the obtained data, the dependence of the fraction of fast states on the initial degree of fi lling has been obtained at diff erent temperatures. It has been shown that the increase in temperature and the increase in the initially fi lled fraction of the volume of nanoporous material lead to a growth in the fraction of fast states with a characteristic time of outfl ow of the order of several seconds.
Author:  S. A. Bortnikova, A. A. Belogorlov
Keywords:  nanoporous material, nonwetting liquid, metastable states, relaxation of a nonwetting liquid
Page:  1521

GRADIENT CARBON COMPOSITE MATERIALS FOR HYDROAGEN PROCESSING TECHNOLOGIES

Consideration is given to the state of the art in the production of materials of carbon felt-based gas diff usion layers. It is shown that the nature of a hydrophobic polymer (polyvinylidene-fl uoride, PVDF, and polytetrafl uorethylene, PTFE) has no crucial eff ect on the water contact angle (limiting wetting angle), however, it is of fundamental signifi cance in terms of regulation of the macroporous structure and surface electrical resistance of the obtained materials. Thus, polytetrafl uorethylene concentrates predominantly in the near-surface layers while polyvinylidenefl uoride spreads uniformly through the thickness of the carbon support. Furthermore, the concentration of an impregnating solution of PTFE (fl uorine plastic) suspension makes it possible to regulate effi ciently the surface properties of felts, which can be directly used in the development of gas diff usion layers of fuel cells. On the whole, the use of viscose fi ber-based carbon felts allows the production of gas diff usion materials with a level of surface electrical resistance below 1 Ω/m2 .
Author:  E. A. Danilov, A. B. Shakhnazarova, O. N. Volkova, D. S. Krisova, V. M. Samoilov, A. R. Gareev
Keywords:  gas diff usion layer, carbon felt cloth, hydrophobization, porosity, electrical conductivity, fuel cell
Page:  1526

OBTAINING HIGHLY-PERMEABLE POROUS SUBSTRATES FROM POLYACRYLONITRILE

A highly-permeable porous membrane with a selective layer from polyacrylonitrile on a nonwoven substrate from polyethylene terephthalate with a pore size of 56 nm, which possesses a water permeability of 310 L/(m2 ∙h∙atm), has been obtained. This makes it promising for use as the substrate in creating gas-distribution and nanofi ltration membranes.
Author:  A. P. Nebesskaya, A. V. Balynin, A. A. Yushkin, A. V. Volkov
Keywords:  composite membrane, ultrafi ltration, polyacrylonitrile, substrate
Page:  1535

MEMBRANE MATERIALS FOR SEPARATION OF HYDROGEN FROM PROCESS GAS MIXTURES

Consideration is given to modern industrial materials for manufacture of membranes oriented toward hydrogen separation from process gas mixtures. Mechanisms for separation of gases on membranes of various materials are given. Fundamental advantages and disadvantages of polymer and metal membranes and also areas for their development are shown
Author:  A. V. Varezhkin
Keywords:  : hydrogen, membrane, polymer, polyimide, palladium, permeability, selectivity
Page:  1541

NONWOVEN CALENDERED COPOLY(URETHANE-IMIDE) MATERIALS FOR ULTRAFILTRATION OF SOLUTIONS CONTAINING AGGRESSIVE AMIDE SOLVENTS

Copoly(urethane imides) were synthesized based on dianhydrides of aromatic tetracarboxylic acids (pyromellite acid, diphenyloxide tetracarboxylic acid), diaminodiphenyl ether, toluene diisocyanate and polycaprolactone. The resulting copolymers are thermoplastics in their mechanical properties. Prepolymers of copolymers were electrodeposited from their solutions in amide solvents. As a result, polymer mats with a structure of interwoven cylindrical microfi bers were obtained. Using the method of high-temperature calendering, the structural compaction of the mats was carried out and their deformation-strength properties and porosity were determined. Based on the results of an analysis of the properties of the obtained calendered mats, a conclusion was made about the prospects of their use in creating membranes for ultrafi ltration of acidic aqueous solutions and solutions of amide solvents used in pharmaceutics.
Author:  A. S. Nesterova, E. M. Ivan′kova, G. V. Vaganov, A. L. Didenko, A. M. Kamalov, E. N. Popova, T. S. Anokhina, I. L. Borisov, V. E. Kraft, V. E. Yudin, A. O. Malakhov, V. V. Kudryavtsev
Keywords:  polyimides, copoly(urethane-imides), electrospinning, calendered mats, morphology, mechanical properties, fi ltration materials
Page:  1552

CREATION OF ULTRAFILTRATION HOLLOW FIBER MEMBRANES BASED ON POLYPHENYLENE SULFONE WITH DIFFERENT CHEMICAL STRUCTURE OF END GROUPS

To obtain high-performance ultrafi ltration hollow fi ber membranes, polyphenylene sulfones (PPSF) with diff erent chemical structure of end groups were synthesized. The synthesis of PPSF was carried out in dimethylacetamide at diff erent ratios of 4,4′-dihydroxydiphenyl and 4,4-dichlorodiphenylsulfone monomers. Samples with a predominant content of hydroxyl and chlorine end groups were studied using NMR and GPC methods. For the synthesized polymers, the hydrophilicity of the materials was studied, and phase diagrams were constructed where N-methyl-2-pyrrolidone (NMP) was used as a solvent and polyethylene glycol with an average molecular weight of 400 g/mol (PEG-400) as a porogen. Using the dry-wet spinning method, hollow fi ber membranes with an average pore diameter of 11–13 nm and fi nger-shaped macrovoids in the substrate layer were obtained from PPSF/NMP/PEG-400 (20/60/20 wt.%) spinning solutions. An increase in the share of –OH end groups increases the hydrophilicity of the polymer. This, in turn, made it possible to obtain hollow fi ber membranes based on PPSF–OH with water permeability of 42 L/(m2 ·h), which is 1.8 times greater than the permeability of the PPSF–Cl membrane. Both membranes demonstrate a retention coeffi cient of 94.7–97.3% according to Blue Dextran calibrant (Mw = 70,000 g∙mole–1).
Author:  D. N. Matveev, A. Yu. Raeva, T. S. Anokhina, I. L. Borisov
Keywords:  hollow fi ber membranes, polyphenylene sulfone, ultrafi ltration, synthesis, chemical structure
Page:  1560

MEMBRANE-BASED DEOXYGENATION OF AN ALKANOLAMINE ABSORBENT OF CO2: FORMATION OF COMPOSITE MEMBRANES AND INFLUENCE OF THE TURBULATORS OF THE LIQUID PHASE IN THEM ON THEIR CHARACTERISTICS

The process of removal of the oxygen dissolved in a monoethanolamine-based absorbent from it in gas–liquid membrane contactors for the prevention of the oxidation destruction of this absorbent in the case of its use for the absorption removal of carbon dioxide from the combustion gases was investigated. The infl uence of the parameters of formation of composite membranes on the basis of porous tubular ceramic substrates with a thin selective nonporous polymer layer of a mixture of poly[1-(trimethylsilyl)-1-propyne] and poly(vinyl trimethylsilane) on their gas-transfer properties was determined. With the use of the membranes obtained, the process of removal of the oxygen dissolved in the aqueous solutions of monoethanolamine from them was realized. The possibility of intensifi cation of this process with the use of a fl ow turbulator installed in the liquid part of a membrane contactor was demonstrated.
Author:  D. O. Kalmykov, P. G. Lagutin, A. V. Tsoi, A. V. Volkov, S. D. Bazhenov
Keywords:  membrane contactor, fl ow turbulator, composite membranes, deoxygenation, carbon dioxide
Page:  1567

SOME TASKS OF MODERN LASER TECHNOLOGIES

The effi ciency of drilling and cutting of metals by laser radiation under the infl uence of two lasers, during processing in water and drilling of small holes in ceramics and metal with a high aspect ratio has been determined. The conditions for clearing the channel of laser radiation propagation through the fl ame of burning hydrocarbons, as well as high-quality welding of two identical tapes made of polymer composite materials for several types of tapes have been found. Diamond coatings on a cutting tool made of VK8 hard alloy in the plasma of a laser plasmatron have been obtained, and diagnostics of the plasma and coatings has been carried out. A two-wave pyrometer based on a spectrometer with a diff raction grating for measuring the temperature of a heated surface has been developed.
Author:  A. F. Glova
Keywords:  laser, radiation, remote processing, absorption, scattering, diamond coating, temperature
Page:  1575

REVIEW OF THE LATEST ACHIEVEMENTS ON ATOMIC VAPOR LASER ISOTOPE SEPARATION

A review of the recent literature on the atomic vapor laser isotope separation has been made, and it has revealed the ongoing activity and the focus of eff orts within the community. The most popular elements were those that produce isotopes for the nuclear medicine. It is shown that the atomic vapor laser separation of isotopes is a good choice for this purpose. The optimization of the separation process parameters through their modeling was demonstrated in many works for diff erent isotopes, and it has given a good estimate of the degree of enrichment of diff erent chemical elements with isotopes and of their production rate for a variety of laser and atomic vapor conditions. A fi nal highlight goes to the use of broadband excitation lasers which are capable of increasing the rate of production of isotopes and decreasing the overall costs of the separation process.
Author:  J. Jakutis, P. Bueno, R. W. M. dos Santos, J. W. Neri
Keywords:  atomic vapor laser isotope separation, excitation and ionization lasers, isotopes for nuclear medicine
Page:  1584

SEPARATION OF CARBON ISOTOPES BY HIGH-POWER IR LASER RADIATION

Results of the development of an industrial technology for the enrichment of the 13C isotope on the basis of the multiphoton dissociation of the molecules of a substance under the action of the radiation of a pulsed CO2 laser are presented. The world′s fi rst industrial plant for the 13C enrichment "Uglerod" is described. The physical bases for the eff ective production of 13C with a concentration higher than 99% are considered.
Author:  V. A. Kuz′menko,a V. B. Laptev, V. S. Mezhevov, S. V. Pigul′skii, E. A. Ryabov
Keywords:  laser isotope separation, multiphoton dissociation of molecules, pulsed CO2 laser.
Page:  1590

REASONING ON THE TOPIC "COAL-BASED ENERGY VERSUS THERMONUCLEAR FUSION?"

The paper focuses on the main sources of energy for humankind in the future. The conclusion has been drawn that thermonuclear fusion will be most ecologically friendly. Issues on the development of thermonuclear fusion based on the reaction between heavy hydrogen isotopes (tritium and deuterium) and a potential method of their resolution are reviewed. 
Author:  M. B. Rozenkevich and A. N. Perevezentsev
Keywords:  sources of energy, natural resources, thermonuclear fusion
Page:  1596

THERMAL CONDUCTIVITY AND HEAT CAPACITY OF ABLATIVE THERMAL PROTECTIVE CARBON FIBER

The results of a study of the thermophysical properties of ablative heat-shielding carbon fi ber with a matrix based on phenol-formaldehyde resin randomly reinforced with short carbon fi bers obtained from carbon fabric based on viscose of the "Ural" type are presented. These studies were carried out using diff erential scanning calorimetry, thermogravimetry, and the laser fl ash method. To describe the obtained data, a model is proposed that allows one to estimate the thermal conductivity of the manufactured carbon fi ber
Author:  D. A. Budnik, K. A. Tarasov, V. M. Samoilov, N. N. Goncharova, E. A. Danilov, A. A. Belogorlov, V. A. Vorontsov, A. R. Gareev
Keywords:  thermal-protective composite material, thermal conductivity, heat capacity, laser fl ash method, thermogravimetric analysis (TGA), diff erential scanning calorimetry (DSC), ablation
Page:  1599

OBTAINING AND THERMOPHYSICAL PROPERTIES OF THERMAL LINERS BASED ON SILICONE ELASTOMER FILLED WITH HEXAGONAL BORON NITRIDE

Basic thermophysical and electric-insulation properties of composite fi lm materials based on silicone and hexagonal boron nitride with a content of the heat-conductive fi ller as high as 46 vol.% have been described. The maximum thermal conductivity was 6 W/(m·K) at a thermal-conductivity anisotropy of about 2.0. The obtained materials possessed a high bulk electrical resistance at a constant current of >109 Ω·cm. It has been shown that in the target interval of operating conditions, the thermal diff usivity of a material at diff erent contents of the fi ller depends weakly on temperature, and the thermal decomposition of the binder begins at a temperature no lower than 400o C. It has been established that the cross-linking of silicone under pressure may noticeably (up to 20%) increase the composite′s thermal conductivity and its anisotropy.
Author:  N. S. Romanov, E. A. Danilov, E. M. Gurova, E. A. Grishukhina
Keywords:  thermal interface, thermal conductivity, thermal liner, silicone, hexagonal boron nitride, dielectric properties, thermal diff usivity
Page:  1605

HEAT CAPACITY AND THERMAL CONDUCTIVITY OF A COMPOSITE MATERIAL FROM THERMOPLASTIC PREPREG

A comparative analysis has been made of the thermophysical properties of consolidated plates fabricated from a thermoplastic composite material based on a unidirectional carbon tape and polyphenyl sulfi de by the method of hot pressing and automated tape laying by layer-by-layer laser deposition welding using a robot manipulator. The obtained experimental values of thermal conductivity and heat capacity of these plates agree with a high degree of accuracy with the values of these parameters obtained according to the proposed computational model. The expediency of fabricating high-precision elements by the method of layer-by-layer laser deposition welding has been substantiated. Investigations were carried out with laser-fl ash and diff erential-scanning-calorimetry methods.
Author:  G. S. Sokolov, G. K. Smirnov, A. R. Gareev, A. A. Belogorlov
Keywords:  heat capacity, thermal conductivity, thermoplastic prepreg, automated laying, laser deposition welding
Page:  1613

HEAT CAPACITY AND THERMAL CONDUCTIVITY OF A COMPOSITE MATERIAL FROM THERMOPLASTIC PREPREG

A comparative analysis has been made of the thermophysical properties of consolidated plates fabricated from a thermoplastic composite material based on a unidirectional carbon tape and polyphenyl sulfi de by the method of hot pressing and automated tape laying by layer-by-layer laser deposition welding using a robot manipulator. The obtained experimental values of thermal conductivity and heat capacity of these plates agree with a high degree of accuracy with the values of these parameters obtained according to the proposed computational model. The expediency of fabricating high-precision elements by the method of layer-by-layer laser deposition welding has been substantiated. Investigations were carried out with laser-fl ash and diff erential-scanning-calorimetry methods.
Author:  G. S. Sokolov, G. K. Smirnov, A. R. Gareev, A. A. Belogorlov
Keywords:  heat capacity, thermal conductivity, thermoplastic prepreg, automated laying, laser deposition welding
Page:  1613

DETERMINATION OF THE SORPTION CAPACITY AND SWELLING OF POLY(n-DECYL METHYL SILOXANE) IN THE ATMOSPHERE OF HYDROCARBONS BY THE ELLIPSOMETRY METHOD

The spectroscopic ellipsometry method was used for the fi rst time for investigating the thin layers (l < 300 nm) of the poly(n-decyl methyl siloxane) in the atmosphere of the gaseous n-alkanes CH4, C2H6, and C4H10. The ellipsometric measurements have shown that the thickness of a layer of this polymer and the index of refraction of light by it change in the atmosphere of hydrocarbons. Data on the change in the thickness of a poly(n-decyl methyl siloxane) layer made it possible to calculate the isotherms of its swelling and of the sorption of hydrocarbons in it as well as the Flory–Huggins interaction parameter of this polymer. By the change in the index of refraction of light by specimens of the indicated polymer, the densities of the hydrocarbons C2H6 and C4H10, sorbed in it, and the coeffi cients of their solubility in this polymer at p → 0 were estimated.
Author:  S. E. Sokolov, S. Smirnova, T. S. Rokhmanka, E. A. Grushevenko
Keywords:  polysiloxanes, hydrocarbons, ellipsometry, swelling, sorption, poly(n-decyl methyl siloxane)
Page:  1618

PLASMACHEMICAL PROCESSES OF IRON CORROSION IN A MOIST AIR MEDIUM EXPOSED TO IONIZING RADIATION OF RADIOACTIVE DECAY

Results are presented of experimental and theoretical computation investigations into the iron corrosion rate in a moist air plasma activated by a stationary high-velocity electron beam as a high-energy ionizing β-radiation simulator. Results are provided for numerical calculations of the spatial distribution of the rate of gas ionization by a high-velocity electron beam in a plasmachemical reactor. Experimental data are presented on the corrosion rate as a function of the high-velocity electron beam current (ionizing radiation intensity) and the duration of plasma treatment of iron samples (level of the absorbed radioactive energy dose). It is shown that in the general case the rate of the radiation plasmachemical iron corrosion depends on both the intensity and the level of the absorbed radioactive energy dose. Results are presented of the analysis of the elemental composition and chemical state of the resultant corrosion products located on the surface and in the depth of the oxidized iron layer of the treated samples.
Author:  V. N. Babichev, D. V. Vysotskii, K. É. Galeeva, A. N. Kirichenko, A. A. Nekrasov, A. V. Ugodchikova, N. I. Trushkin, A. V. Filippov, Yu. V. Cherepanova, V. E. Cherkovets
Keywords:  plasma, electron beam, corrosion, radiation, moisture, iron
Page:  1628

THEORETICAL ANALYSIS AND CASE STUDIES OF ONE-DIMENSIONAL ION EXTRACTION PROCESSES

The ion extraction process is one of the most important procedures in laser-induced isotope separation. In our previous study, based on the analysis of sheath evolution and ion rarefaction wave propagation, a theoretical model has been developed for describing the one-dimensional ion extraction process. In this paper, two case studies are conducted by employing this analytical model. Firstly, a barium plasma is selected, since previous experimental studies are focused mainly on barium plasma. A comparison between the analytical and experimental results is made to validate this theoretical model. For a more practical scenario, uranium plasmas are considered, and a systematic analysis of the impact of initial plasma parameters on the ion extraction characteristics is made. The results provide a brief and clear physical description of the one-dimensional ion extraction process, and also provide a guidance for improving the ion extraction effi ciency in actual applications. 
Author:  Yao-Ting Wang, Lan-Yue Luo, He-Ping Li, Dong-Jun Jiang, and Ming-Sheng Zhou
Keywords:  ion extraction process, analytical model, theoretical analysis
Page:  1641

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