scholarly journals Scientific search under the pressure of high responsibility: development of the technology of electromagnetic isotope separation in the framework of the USSR Atomic project

2021 ◽  
Vol 3 (1) ◽  
pp. 120-135
Author(s):  
Vasily Borisov
Keyword(s):  
Atomic Bomb ◽  
Isotope Separation ◽  
Gas Diffusion ◽  
Uranium Isotopes ◽  
Electromagnetic Mass ◽  
The Urals ◽  
Separation Plant ◽  
Electromagnetic Separation ◽  
Design Bureau ◽  
Wide Range

One of the ways to obtain nuclear explosives for the manufacture of the first atomic bombs was the separation of uranium isotopes by electromagnetic (mass spectrographic) method. The theoretical justification and experimental separation of uranium isotopes by this method was carried out by L. A. Artsimovich in the Laboratory No. 2 of the USSR Academy of Sciences. By the middle of 1945, L. A. Artsimovich had obtained results at the experimental facility indicating the possibility of stable enrichment of uranium with the U-235 isotope using this method. Having the results of the experiments, the Design Bureau at the “Electrosila” plant (D. V. Efremov), with the participation of the Research Vacuum Institute (S. A. Vekshinsky) and the “A” Institute (M. Ardenne), developed a project of an industrial multi-chamber installation for electromagnetic separation of uranium isotopes SU-20. Such an installation was manufactured and put into operation at the newly created plant in the Urals, which allowed in 1951 to obtain the necessary amount of uranium-235 for the RDS-3 atomic bomb. After 1952, the technology of electromagnetic separation was no more used for the separation of uranium isotopes due to the improvement of more productive equipment for gas-diffusion separation of isotopes. The equipment of the electromagnetic isotope separation plant built in the Urals was used to produce lithium-6, needed to equip the first thermonuclear charge, which was successfully tested in 1953. In the next years, the electromagnetic isotope separation plant was involved in the manufacture of isotope products for scientific, technical and medical applications at wide range of utilization in Russia and abroad.

scholarly journals Gas Damping in Capacitive MEMS Transducers in the Free Molecular Flow Regime

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2566
Author(s):  
Boris A. Boom ◽  
Alessandro Bertolini ◽  
Eric Hennes ◽  
Johannes F. J. van den Brand
Keyword(s):  
Flow Regime ◽  
Gas Diffusion ◽  
Diffusion Time ◽  
Molecular Flow ◽  
Free Molecular Flow ◽  
Simple Analytical Model ◽  
Gas Damping ◽  
Wide Range ◽  
Capacitive Mems ◽  
Insight Into

We present a novel analysis of gas damping in capacitive MEMS transducers that is based on a simple analytical model, assisted by Monte-Carlo simulations performed in Molflow+ to obtain an estimate for the geometry dependent gas diffusion time. This combination provides results with minimal computational expense and through freely available software, as well as insight into how the gas damping depends on the transducer geometry in the molecular flow regime. The results can be used to predict damping for arbitrary gas mixtures. The analysis was verified by experimental results for both air and helium atmospheres and matches these data to within 15% over a wide range of pressures.

scholarly journals Holistic Approach to Design, Test, and Optimize Stand-Alone SOFC-Reformer Systems

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 348
Author(s):  
Michael Höber ◽  
Benjamin Königshofer ◽  
Philipp Wachter ◽  
Gjorgji Nusev ◽  
Pavle Boskoski ◽  
...  
Keyword(s):  
Rural Communities ◽  
High Efficiency ◽  
Diffusion Processes ◽  
Holistic Approach ◽  
Maximum Error ◽  
Gas Diffusion ◽  
Electrochemical Analysis ◽  
Internal Reforming ◽  
Operation Conditions ◽  
Wide Range

Reliable electrical and thermal energy supplies are basic requirements for modern societies and their food supply. Stand-alone stationary power generators based on solid oxide fuel cells (SOFC) represent an attractive solution to the problems of providing the energy required in both rural communities and in rurally-based industries such as those of the agricultural industry. The great advantages of SOFC-based systems are high efficiency and high fuel flexibility. A wide range of commercially available fuels can be used with no or low-effort pre-treatment. In this study, a design process for stand-alone system consisting of a reformer unit and an SOFC-based power generator is presented and tested. An adequate agreement between the measured and simulated values for the gas compositions after a reformer unit is observed with a maximum error of 3 vol% (volume percent). Theoretical degradation free operation conditions determined by employing equilibrium calculations are identified to be steam to carbon ratio (H2O/C) higher 0.6 for auto-thermal reformation and H2O/C higher 1 for internal reforming. The produced gas mixtures are used to fuel large planar electrolyte supported cells (ESC). Current densities up to 500 mA/cm2 at 0.75 V are reached under internal reforming conditions without degradation of the cells anode during the more than 500 h long-term test run. More detailed electrochemical analysis of SOFCs fed with different fuel mixtures showed that major losses are caused by gas diffusion processes.

scholarly journals Uranium Isotopes Separation Technique

2015 ◽  
Vol 56 ◽  
pp. 37-46
Author(s):  
Iman Tarik Al-Alawy ◽  
Raghad Saadoon Mohammed ◽  
Mohammed Zorah Hassan ◽  
Waleed Jabar Mhanah
Keyword(s):  
Simple Model ◽  
Objective Function ◽  
Isotope Separation ◽  
Separation Technique ◽  
Optimization Process ◽  
Uranium Isotopes ◽  
Physical Processes ◽  
Ion Extraction ◽  
Laser Isotope Separation ◽  
Isotopes Separation

This work describes the atomic laser isotope separation (LIS). The (LIS) plant means calculating the values of a large number of parameters in order to optimize some objective function. Here we use simple model to describe the elementary physical processes: evaporation, vapor expansion, interaction between photons and atoms, ion extraction etc...concentrated on theoretical and empirical bases. An optimization process for the separation of Uranium isotopes is described and discussed.

scholarly journals Quantifying phosphoric acid in high-temperature polymer electrolyte fuel cell components by X-ray tomographic microscopy

2014 ◽  
Vol 21 (6) ◽  
pp. 1319-1326 ◽  
Author(s):  
S. H. Eberhardt ◽  
F. Marone ◽  
M. Stampanoni ◽  
F. N. Büchi ◽  
T. J. Schmidt
Keyword(s):  
High Temperature ◽  
Fuel Cell ◽  
Phosphoric Acid ◽  
Polymer Electrolyte ◽  
Diffusion Layer ◽  
Gas Diffusion Layer ◽  
Gas Diffusion ◽  
X Ray ◽  
Wide Range ◽  
Cell Components

Synchrotron-based X-ray tomographic microscopy is investigated for imaging the local distribution and concentration of phosphoric acid in high-temperature polymer electrolyte fuel cells. Phosphoric acid fills the pores of the macro- and microporous fuel cell components. Its concentration in the fuel cell varies over a wide range (40–100 wt% H3PO4). This renders the quantification and concentration determination challenging. The problem is solved by using propagation-based phase contrast imaging and a referencing method. Fuel cell components with known acid concentrations were used to correlate greyscale values and acid concentrations. Thus calibration curves were established for the gas diffusion layer, catalyst layer and membrane in a non-operating fuel cell. The non-destructive imaging methodology was verified by comparing image-based values for acid content and concentration in the gas diffusion layer with those from chemical analysis.

A book review: The History of Ural Literature. 19th century. In 2 vols. Ed. by E. K. Sozina. Moscow, Publishing house JASK, 2021, vol. 1. 664 p.; vol. 2. 778 p.

2021 ◽  
pp. 335-339
Author(s):  
Tatyana I. Rozhkova ◽  
Keyword(s):  
Publishing House ◽  
Self Determination ◽  
Writing Style ◽  
The Urals ◽  
Process Understanding ◽  
Wide Range ◽  
Literary Process ◽  
History Of ◽  
Genre Preferences

The review deals with the second volume of the academic edition “The History of Ural Literature,” prepared by a group of scholars from the Ural-Siberian scientific community. The merit of the issue is presenting the literary process and the Ural writers’ community as a complex sociocultural phenomenon aimed at work professionalization and connected with the history of the region’s self-determination. When presenting specific names, the authors of the project followed the principle description tasks: to show the connection of the writer’s biography and work with the territory, to emphasize how the works are filled with impressions of Ural life, to draw attention to the writer’s involvement in local cultural communities and support from leading literary figures and critics. Since the book covers a wide range of authors, a number of conclusions significant for the regional literary process understanding can be drawn. Biography materials allow speaking of a variety of social segments of people involved in writing: from base estates and plant workers to noble and intellectual people. Not everyone was ready for professional literary activity, but all quite openly demonstrated their reading tastes. By the end of the century, the cultural and aesthetic commonality of the Ural literature is defined. Its specific writing style becomes distinctive, with a tendency toward documentality, autobiography, and ethnography. Genre preferences become apparent. Genre preferences become apparent. Most importantly, the names appear, starting to be identified by critics as “the Urals writer.”

A Chemical Exchange System for Isotopic Feed to a Nitrogen and Oxygen Isotope Separation Plant

1989 ◽  
Vol 24 (5-6) ◽  
pp. 415-428 ◽  
Author(s):  
T. R. Mills ◽  
M. G. Garcia ◽  
R. C. Vandervoort ◽  
B. B. McInteer
Keyword(s):  
Oxygen Isotope ◽  
Chemical Exchange ◽  
Isotope Separation ◽  
Exchange System ◽  
Separation Plant

scholarly journals EUCLIDEAN RESONANCE: APPLICATION TO PHYSICAL AND CHEMICAL EXPERIMENTS

2006 ◽  
Vol 20 (06) ◽  
pp. 627-658 ◽  
Author(s):  
B. IVLEV
Keyword(s):  
Electric Fields ◽  
Isotope Separation ◽  
Nuclear Fission ◽  
Particle Decay ◽  
Semiclassical Methods ◽  
Wide Range ◽  
Tunnel Barriers ◽  
Physical And Chemical ◽  
Nuclear Processes ◽  
Complex Trajectories

The phenomenon of Euclidean resonance (a strong enhancement of quantum tunneling through a nonstationary potential barrier) is applied to disintegration of atoms and molecules through tunnel barriers formed by applied constant and time-dependent electric fields. There are two different channels for such disintegration, electronic and ionic. The electronic mechanism is associated with the ionization of a molecule into an electron and a positive ion. The required frequencies are in a wide range between 100 MHZ and infrared. This mechanism may constitute a method of selective destruction of chemical bonds. The ionic mechanism consists of dissociation of a molecule into two ions. Since an ion is more massive than an electron, the necessary frequency is about 1 MHZ. This provides a theoretical possibility of a different method of isotope separation by radio frequency waves. The small sub-barrier tunneling probability of nuclear processes can be dramatically enhanced by collision with incident charged particles. Semiclassical methods of theory of complex trajectories have been applied to nuclear tunneling, and conditions for the effect have been obtained. The enhancement of α particle decay by incident proton with energy of about 0.25 MeV has been demonstrated. The general features of this process are common for other sub-barrier nuclear processes and can be applied to nuclear fission.

Modeling and Simulation of Flow and Uranium Isotopes Separation in Gas Centrifuges Using Implicit Coupled Density-Based Solver in OpenFOAM

2020 ◽  
Author(s):  
Valiyollah Ghazanfari ◽  
Ali Akbar Salehi ◽  
Ali Reza Keshtkar ◽  
Mohammad Mahdi Shadman ◽  
Mohammad Hossein Askari
Keyword(s):  
Gas Flow ◽  
Isotope Separation ◽  
Splitting Method ◽  
Flow Characteristics ◽  
Uranium Isotopes ◽  
Gas Centrifuge ◽  
Total Reflux ◽  
Axial Mass ◽  
Fluent Software ◽  
Isotopes Separation

The performance of a gas centrifuge that is used for isotopes separation is dependent on the gas flow inside it. In this study, for modeling the UF6 gas flow, an Implicit Coupled Density-Based (ICDB) solver, was developed in OpenFOAM. To validate the ICDB solver, the gas flow within the rotor in total reflux state was compared with the analytical solution obtained by Onsager model and the numerical solution obtained by the Fluent software. The results showed that the ICDB solver had acceptable accuracy and validity. Also the computational efficiency of Roe, AUSM (Advection Upstream Splitting Method) and AUSM+ up schemes were compared. The results showed AUSM+ up scheme is efficient. Then, the uranium isotopes separation in a gas centrifuge was simulated. It was revealed that all gas flow characteristics including velocity, pressure, temperature and axial mass flux, as well as uranium isotope separation parameters including separation power and separation coefficients could well be predicted.

Investigation of Gas Diffusion Layer Properties Using X-Ray Microtomography

2015 ◽  
Author(s):  
Sadegh Hasanpour ◽  
Andre Phillion ◽  
Mina Hoorfar
Keyword(s):  
Diffusion Layer ◽  
Proton Exchange Membrane ◽  
Gas Diffusion Layer ◽  
Gas Diffusion ◽  
Proton Exchange ◽  
New Method ◽  
Surface Topology ◽  
X Ray ◽  
Rolling Ball ◽  
Wide Range

An essential part of proton exchange membrane fuel cells (PEMFCs) is the gas diffusion layer (GDL), which provides pathways for by-products to be removed from PEMFCs. One of the main properties of GDLs is porosity. The two widely used experimental methods for finding the porosity of GDLs are mercury intrusion porosimetry (MIP) and method of standard porosimetry (MSP). In addition to these methods, the porosity of GDLs can be calculated based on the high resolution 3D images that are acquired using X-ray microtomography (μXCT) as shown in recent studies (e.g., [7,12]). Despite the general success of using μXCT to measure GDL porosity, different porosity values have been reported for similar GDLs. These variations are due to different assumptions made for determining the surface of the sample, and hence, its external dimensions. In this research, current methods used for calculating porosity of GDLs from μXCT images are discussed, and a new surface identification method based on a rolling ball algorithm is introduced. The main advantage of this new method is that variations in surface topology or roughness are taken into account when calculating porosity. The new method is not only applicable to GDLs, but can be applied to characterize a wide range of highly porous media.

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