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Rull cave is a karstic cave located in Vall d’Ebo (Alicante, Southeast of Spain) developed in massive Miocene conglomerates and Cretaceous limestones. Processes in soil above Rull cave and outdoor atmosphere directly influence the underground environment of the cave. Continuous and discrete monitoring of cave atmosphere and soil (from 2012 to 2022) allows to characterise the spatial distribution and temporal variations of the gaseous concentration (222Rn and CO2) and understand the relationship between the processes which occurred in the 3-component system (soil-cave-atmosphere). Besides the presence of visitors, Rull cave maintains stable values of mean temperature (16.2 °C) and relative humidity (97.6%). In an annual cycle the cave presents two different gaseous stages (stagnation and ventilation). Maximum average values of CO2 and 222Rn concentration are reached within the stagnation stage, in the warmest period of the year. On the contrary, in the ventilation stage (in the coldest months) the cave reaches the lowest concentrations in its inner atmosphere. For the study period, daily average CO2 and 222Rn concentrations are 2008 ppm and 1745 Bq/m3, respectively. Results show that the dynamics of 222Rn and CO2 in the cave air follow different patterns defined by the complex relationships between external and internal factors. Findings from this study provide substantial information about the environmental situation of the cave atmosphere in terms of air quality for visitors and workers.

Rull cave is a karstic cave located in Vall d’Ebo (Alicante, Southeast of Spain) developed in massive Miocene conglomerates and Cretaceous limestones. Processes in soil above Rull cave and outdoor atmosphere directly influence the underground environment of the cave. Continuous and discrete monitoring of cave atmosphere and soil (from 2012 to 2022) allows to characterise the spatial distribution and temporal variations of the gaseous concentration (222Rn and CO2) and understand the relationship between the processes which occurred in the 3-component system (soil-cave-atmosphere). Besides the presence of visitors, Rull cave maintains stable values of mean temperature (16.2 °C) and relative humidity (97.6%). In an annual cycle the cave presents two different gaseous stages (stagnation and ventilation). Maximum average values of CO2 and 222Rn concentration are reached within the stagnation stage, in the warmest period of the year. On the contrary, in the ventilation stage (in the coldest months) the cave reaches the lowest concentrations in its inner atmosphere. For the study period, daily average CO2 and 222Rn concentrations are 2008 ppm and 1745 Bq/m3, respectively. Results show that the dynamics of 222Rn and CO2 in the cave air follow different patterns defined by the complex relationships between external and internal factors. Findings from this study provide substantial information about the environmental situation of the cave atmosphere in terms of air quality for visitors and workers.

6H polytype silicon carbide (SiC) samples of n-type have been implanted with 50-keV H(+) ions and subsequently annealed at temperatures between 200 and 1150 C. Using depth profiling by secondary ion mass spectrometry, the motion of hydrogen is observed in the implanted region for temperatures above 700 C. A diffusion coefficient of about 10 exp -14 sq cm/s is extracted at 800 C with an approximate activation energy of about 3.5 eV. Hydrogen displays strong interaction with the implantation-induced defects, and stable hydrogen-defect complexes are formed. These complexes anneal out at temperatures in excess of 900 C, and are tentatively identified as carbon-hydrogen centers at a Si vacancy., QC 20100524

In order to predict the first density corrections to the transport properties of gases, it is necessary to consider collision integrals that account for the effects of collisions among three molecules. For a gas of hard spherical molecules such three-particle collision integrals can be decomposed into collision integrals associated with sequences of one, two, three, and four successive collisions among three molecules. In the present technical report the authors calculate these three-particle collision integrals for the coefficients of thermal conductivity, viscosity, and self-diffusion., See also report dated Sep 1972, AD0749514.

Research on slow ions in gases is described. The research dealt with the measurement of ionic mobilities, diffusion coefficients, and reaction rates. Emphasis was placed on studies of clustering of K(+) ions in N2, H2, He, Ne, Ar, 02, NO, CO, and CO2; on tests of the Wannier diffusion equations; on the differences in behavior of K(+) ions in N2 and CO; and on measurements on ions, formed from CO, drifting in carbon monoxide gas. Improvements in the experimental apparatus and analytical techniques are described. (Modified author abstract)

Two additional high vacuum permeability stations suitable for time lag measurements of the diffusion constants have been built and are very briefly described. The permeabilities, diffusivities and solubilities of helium, neon, argon, oxygen, nitrogen and carbon dioxide have been measured at various temperatures in polyacrylonitrile. The activation energies, heat of solution and the preexponential factors have been calculated. Abnormally low permeability and diffusion constants were found with high activation energies. Some reasons for this behavior are presented. The corresponding transport behavior of helium, neon, argon, krypton and nitrogen in polystyrene has also been measured and the results presented together with the known values for oxygen, and carbon dioxide. (Modified author abstract)

The authors have used a drift tube mass spectrometer to measure the mobilities and longitudinal diffusion coefficients of K(+) ions in argon at 300K. The range of E/N extends from 1 to 610 Td, where E is the electric field intensity and N is the number density of the neutral gas. The zero-field reduced mobility of K(+) in argon was found. The diffusion coefficient data is compared with values obtained from the Wannier theory for motion of ions in strong electric fields. Also included are tabulated transport data for K(+) in Ar, N2, and CO. (Author)

A unified model relating surface variables to the nucleate pool boiling characteristics was developed. A simple vapor trapping mechanism was postulated and a geometrical model constructed for idealized conical cavities relating the effective radius for nucleation to cavity radius, cone angle and contact angle. This model for individual cavities was extended to the entire surface providing an expression for the cumulative site density in terms of geometrical parameters. A gas diffusion technique was developed to measure the effective radius for natural cavities and was used successfully to verify the nucleation criteria Delta T = 2(sigma)(T sub s)(V sub fg)/h(fg)rho. A transient heat conduction model was esxperimentally verified for water and organics at atmospheric pressure and was incorporated into a unified expression showing explicitly the role of surface geometry and contact angle. (Author)

The purpose of the paper is to show how perturbation methods may be used to obtain asymptotic solutions of the equations describing the combined process of diffusion and multiple-step chemical reactions. As an example, the diffusional kinetics of high altitude chemical releases are analyzed. (Author)

The authors have measured, with a drift tube mass spectrometer, the mobilities and longitudinal diffusion coefficients of K(+) ions in nitrogen and carbon monoxide at 300K. The zero-field reduced mobilities of K(+) ions in N2 and CO were determined. The experimental diffusion coefficients were compared with the predictions of an equation developed by Wannier on the assumption that the ion-molecule interaction consists of only the attractive polarization force. Comparison is also made with a modified version of this equation which contains the ionic drift velocity rather than the mean free time. Also observed was the clustering of single molecules of CO2, NO, CO, N2, O2, Ar, D2, Ne, and He to K(+) ions.

The transport properties of a dilute gas are determined by binary collision integrals. In order to predict the first density corrections to the transport properties, it is necessary to consider collision integrals that account for the effects of collisions among three molecules. In the report, the authors derive and formulate such three-particle collision integrals for the coefficients of thermal conductivity, viscosity, and self-diffusion of a gas of hard spherical molecules.

Research on slow ions in gases with a drift tube mass spectrometer is described. The research dealt with the measurement of ionic mobilities, diffusion coefficients, and reaction rates. Emphasis was placed on studies of clustering of K(+) ions in N2, H2, He, Ne, Ar, O2, NO, CO, and CO2; on tests of the Wannier diffusion equations; on the differences in behavior of K(+) ions in N2 and CO; and on measurement on ions, formed from CO, drifting in carbon monoxide gas. Improvements in the experimental apparatus and analytical techniques are described, and plans for the immediate future are discussed. (Author)

The report examines the following: the basic types of gas fuel and methods of obtaining it; physical and chemical properties both of fuel gases and of the products of their combustion, along with the basic questions connected with the combustion process, such as the mechanism of the interaction of the fuel gas with air, ignition of the gas/air mixture, and carburation in laminar and turbulent flames during combustion of both pure gas and a gas/air mixture. Attention is also given to questions of the movement of gas over pipes and other channels with determination of the pressure losses which occur., Edited machine trans. of mono. Goryuchie Gazy i ikh Svoistva, Leningrad, 1970 p1-128

A variational method has been developed to account for the effect of diffusion on laser induced breakdown. The method is applicable for arbitrary distributions of intensity in the focal volume. It has been specifically applied to the calculation of breakdown for Gaussian spots, and found to yield breakdown intensities differing by nearly a factor of 2 from calculations employing simplified diffusion models. (Author)

Cílem bakalářské práce je shrnout poznatky o možnostech a důvodech obohacování jaderného paliva. Popsat jednotlivé způsoby obohacování se zaměřením na jejich historii, princip funkce, energetické a technologické nároky a účinnosti jednotlivých metod. Poukázat na značnou náročnost procesu a provést ekonomickou rozvahu jednotlivých metod., The aim of this bachelor thesis is to review the current knowledge and possibilities dealing with an enrichment of the nuclear fuel and to describe particular methods of the enrichment. An attention is paid to basic principles, functions, technological and power requirements and efficiency of the discussed methods. In conclusion, a difficulty of the enrichment process is pointed out and a balance sheet of the economic impact is made.

Cílem bakalářské práce je shrnout poznatky o možnostech a důvodech obohacování jaderného paliva. Popsat jednotlivé způsoby obohacování se zaměřením na jejich historii, princip funkce, energetické a technologické nároky a účinnosti jednotlivých metod. Poukázat na značnou náročnost procesu a provést ekonomickou rozvahu jednotlivých metod., The aim of this bachelor thesis is to review the current knowledge and possibilities dealing with an enrichment of the nuclear fuel and to describe particular methods of the enrichment. An attention is paid to basic principles, functions, technological and power requirements and efficiency of the discussed methods. In conclusion, a difficulty of the enrichment process is pointed out and a balance sheet of the economic impact is made.

Cílem bakalářské práce je shrnout poznatky o možnostech a důvodech obohacování jaderného paliva. Popsat jednotlivé způsoby obohacování se zaměřením na jejich historii, princip funkce, energetické a technologické nároky a účinnosti jednotlivých metod. Poukázat na značnou náročnost procesu a provést ekonomickou rozvahu jednotlivých metod., The aim of this bachelor thesis is to review the current knowledge and possibilities dealing with an enrichment of the nuclear fuel and to describe particular methods of the enrichment. An attention is paid to basic principles, functions, technological and power requirements and efficiency of the discussed methods. In conclusion, a difficulty of the enrichment process is pointed out and a balance sheet of the economic impact is made.

Cílem bakalářské práce je shrnout poznatky o možnostech a důvodech obohacování jaderného paliva. Popsat jednotlivé způsoby obohacování se zaměřením na jejich historii, princip funkce, energetické a technologické nároky a účinnosti jednotlivých metod. Poukázat na značnou náročnost procesu a provést ekonomickou rozvahu jednotlivých metod., The aim of this bachelor thesis is to review the current knowledge and possibilities dealing with an enrichment of the nuclear fuel and to describe particular methods of the enrichment. An attention is paid to basic principles, functions, technological and power requirements and efficiency of the discussed methods. In conclusion, a difficulty of the enrichment process is pointed out and a balance sheet of the economic impact is made.

Cílem bakalářské práce je shrnout poznatky o možnostech a důvodech obohacování jaderného paliva. Popsat jednotlivé způsoby obohacování se zaměřením na jejich historii, princip funkce, energetické a technologické nároky a účinnosti jednotlivých metod. Poukázat na značnou náročnost procesu a provést ekonomickou rozvahu jednotlivých metod., The aim of this bachelor thesis is to review the current knowledge and possibilities dealing with an enrichment of the nuclear fuel and to describe particular methods of the enrichment. An attention is paid to basic principles, functions, technological and power requirements and efficiency of the discussed methods. In conclusion, a difficulty of the enrichment process is pointed out and a balance sheet of the economic impact is made.