scholarly journals The use of underground thermal gradients as technique for soil radon mitigation

2021 ◽  
Author(s):  
Francisco J. Arias ◽  
Salvador De Las Heras
Keyword(s):  
Diffusion Coefficient ◽  
Diffusion Coefficients ◽  
Thermal Gradient ◽  
Short Note ◽  
Point Of View ◽  
Thermal Gradients ◽  
Theoretical Point ◽  
Cold Regions ◽  
Standard Temperature ◽  
Soil Radon

Diffusion coefficients of radon through minerals and rocks are characterised by Arrhenius linear plots, i.e., increasing with temperature. It has been observed, for example, that rocks with a mild heating (<100°C) translate into a radon release that can be enhanced 100–1,000 times than the normal release at STP (Standard Temperature Pressure (STP). Therefore, it is reasonable to think that if the soil is deliberately heated creating a thermal gradient, it could be possible, at least from a theoretical point of view, to thermally pump radon from soil because the radon atoms will escape preferentially from cold regions (low diffusion coefficient) towards hot regions (high diffusion coefficients) if a radon sink is located. In this short note, this approach for soil radon removal is investigated.

Thermal Soil Radon Mitigation

2021 ◽  
Author(s):  
Francisco Arias ◽  
Salvador De Las Heras
Keyword(s):  
Diffusion Coefficient ◽  
Thermal Energy ◽  
Diffusion Coefficients ◽  
Solar Thermal ◽  
Dimensional Model ◽  
Solar Thermal Energy ◽  
Cold Regions ◽  
One Dimensional ◽  
Soil Radon ◽  
Mitigation Technique

Abstract In this work consideration is given to the possibility for thermal soil radon mitigation. It is known that the diffusion coefficient of radon through minerals and rocks have are characterized by Arrhenius linear plots increasing inasmuch that temperature increases. For the case of rocks, for example, it was observed that a mild heating -less than 100$^o$C, translates into a radon release which can be enhanced by 100 to 1000 times than the normal release at STP. Therefore, it is reasonable to think that if soil is deliberately heated -for example, harnessing solar thermal energy, it is reasonable to think that it could be possible to pump radon from soil because the radon atoms will escape preferentially from cold regions (low diffusion coefficient) toward hot regions (high diffusion coefficients) where a radon sink is located. Utilizing a simplified two-group thermal one-dimensional model an expression was derived which allows a first assessment on this new mitigation technique

scholarly journals Study on the Separation of H2 from CO2 Using a ZIF-8 Membrane by Molecular Simulation and Maxwell-Stefan Model

Molecules ◽  
2019 ◽  
Vol 24 (23) ◽  
pp. 4350 ◽  
Author(s):  
Behrouz Bayati ◽  
Asma Ghorbani ◽  
Kamran Ghasemzadeh ◽  
Adolfo Iulianelli ◽  
Angelo Basile
Keyword(s):  
Molecular Simulation ◽  
Diffusion Coefficients ◽  
Diffusion Processes ◽  
Langmuir Model ◽  
Separation Process ◽  
Point Of View ◽  
Theoretical Point ◽  
Zeolitic Imidazolate Framework ◽  
Adsorption Of Co2 ◽  
And Diffusion

The purification of H2-rich streams using membranes represents an important separation process, particularly important in the viewpoint of pre-combustion CO2 capture. In this study, the separation of H2 from a mixture containing H2 and CO2 using a zeolitic imidazolate framework (ZIF)-8 membrane is proposed from a theoretical point of view. For this purpose, the adsorption and diffusion coefficients of H2 and CO2 were considered by molecular simulation. The adsorption of these gases followed the Langmuir model, and the diffusion coefficient of H2 was much higher than that of CO2. Then, using the Maxwell–Stefan model, the H2 and CO2 permeances and H2/CO2 permselectivities in the H2–CO2 mixtures were evaluated. Despite the fact that adsorption of CO2 was higher than H2, owing to the simultaneous interference of adsorption and diffusion processes in the membrane, H2 permeation was more pronounced than CO2. The modeling results showed that, for a ZIF-8 membrane, the H2/CO2 permselectivity for the H2–CO2 binary mixture 80/20 ranges between 28 and 32 at ambient temperature.

Fission Gas Bubbles in Fractured UO2

1968 ◽  
Vol 26 ◽  
pp. 286-287
Author(s):  
O. M. Katz
Keyword(s):  
Electron Microscopy ◽  
Thermal Gradient ◽  
Gas Bubbles ◽  
Inert Gas ◽  
Thermal Gradients ◽  
Fission Gas ◽  
Beam Heating ◽  
Limited Application ◽  
Bubble Characteristics ◽  
Electron Beam Heating

The swelling of irradiated UO2 has been attributed to the migration and agglomeration of fission gas bubbles in a thermal gradient. High temperatures and thermal gradients obtained by electron beam heating simulate reactor behavior and lead to the postulation of swelling mechanisms. Although electron microscopy studies have been reported on UO2, two experimental procedures have limited application of the results: irradiation was achieved either with a stream of inert gas ions without fission or at depletions less than 2 x 1020 fissions/cm3 (∼3/4 at % burnup). This study was not limited either of these conditions and reports on the bubble characteristics observed by transmission and fractographic electron microscopy in high density (96% theoretical) UO2 irradiated between 3.5 and 31.3 x 1020 fissions/cm3 at temperatures below l600°F. Preliminary results from replicas of the as-polished and etched surfaces of these samples were published.

Timber Auctions in the Context of the Modern Auction Theory

2007 ◽  
pp. 86-94
Author(s):  
A. Manakov
Keyword(s):  
Theoretical Analysis ◽  
Auction Theory ◽  
Point Of View ◽  
Theoretical Point ◽  
English Auction ◽  
Analysis And Evaluation

The article provides theoretical analysis and evaluation of the timber auctions reforms in Russia. The author shows that the mechanism of the "combined auctions", which functioned until recently, is more appropriate from the theoretical point of view (and from the point of view of the Russian practice) as compared to the officially approved format of the English auction.

A novel cryptosystem based on abstract automata and Latin cubes

2015 ◽  
Vol 52 (2) ◽  
pp. 221-232
Author(s):  
Pál Dömösi ◽  
Géza Horváth
Keyword(s):  
Block Cipher ◽  
Finite Automata ◽  
Theoretical Background ◽  
Point Of View ◽  
Theoretical Point ◽  
Transition Matrices ◽  
Encryption And Decryption ◽  
Secret Keys ◽  
Automata Network ◽  
Fully Functioning

In this paper we introduce a novel block cipher based on the composition of abstract finite automata and Latin cubes. For information encryption and decryption the apparatus uses the same secret keys, which consist of key-automata based on composition of abstract finite automata such that the transition matrices of the component automata form Latin cubes. The aim of the paper is to show the essence of our algorithms not only for specialists working in compositions of abstract automata but also for all researchers interested in cryptosystems. Therefore, automata theoretical background of our results is not emphasized. The introduced cryptosystem is important also from a theoretical point of view, because it is the first fully functioning block cipher based on automata network.

Graffiti als Version und Subversion–Praxen kultureller Re-Regulierung und die Möglichkeit von Gratiforschung

2010 ◽  
Vol 55 (2) ◽  
pp. 11-25 ◽  
Author(s):  
Bernd Dollinger
Keyword(s):  
Social Life ◽  
Point Of View ◽  
Theoretical Point ◽  
Research Practice ◽  
Wird Eine ◽  
Multiple Perspectives

Der Beitrag geht von Versuchen aus, integrative Perspektiven einer überaus heterogenen Graffitiforschung zu bestimmen. In Auseinandersetzung insbesondere mit Bruno Latours Ansatz des »Iconoclash« wird eine kulturtheoretische Referenz bestimmt, die Graffiti als Version identifiziert, d. h. als semiotisch orientierte Veränderung räumlich situierter Ordnungs- und Regulierungspraxen. Ihnen kann, wenn auch nicht zwingend, eine subversive Qualität zukommen. Durch die Ausrichtung am Konzept einer Version wird beansprucht, Forderungen einer normativ weitgehend abstinenten, nicht-essentialistischen und für komplexe Fragen der Identitäts- und Raumpolitik offenen Forschungspraxis einzulösen.<br><br>The contribution attempts to integrate multiple perspectives of current largely heterogeneous graffiti scholarship. Referring to Bruno Latour’s concept »iconoclash«, we discuss graffiti from a cultural-theoretical point of view as a »version«. It appears as a semiotically oriented modification of spatially situated practices that regulate social life. Often, but not necessarily, these practices involve subversive qualities. The concept of »version« facilitates a non-normative and non-essentialist strategy of research. This enables an explorative research practice in which the complex matters of identity and space politics that are associated with graffiti can be addressed.

Toward living nanomachines

2018 ◽  
Author(s):  
Christof Mast ◽  
Friederike Möller ◽  
Moritz Kreysing ◽  
Severin Schink ◽  
Benedikt Obermayer ◽  
...  
Keyword(s):  
Molecular Evolution ◽  
Thermal Gradient ◽  
Molecular Level ◽  
Minimal System ◽  
Thermal Gradients ◽  
Temperature Oscillations ◽  
Fluid Convection ◽  
Inanimate Matter ◽  
High Concentrations ◽  
Periodic Temperature

How does inanimate matter become transformed into animate matter? Living systems evolve by replication and selection at the molecular level and this chapter considers how to establish a synthetic, minimal system that can support molecular evolution and thus life. Molecular evolution cannot be explained by starting with high concentrations of activated chemicals that react toward their chemical equilibrium; persistent non-equilibria are required to maintain continuous reactivity and we especially consider thermal gradients as an early driving force for Darwinian molecular evolution. The temperature difference across water-filled compartments implements a laminar fluid convection with periodic temperature oscillations that allow for the melting and replication of DNA. Simultaneously, dissolved molecules are moved along the thermal gradient by an effect called thermophoresis. The combined result is an efficient molecule trap that exponentially favors long over short DNA and thus maintains complexity. Future experiments will reveal how thermal gradients could actively drive the Darwinian process of replication and selection.

scholarly journals How Digital Inclusion Increase Opportunities for Young People: Case of NEETs from Bulgaria, Romania and Turkey

2021 ◽  
Vol 13 (14) ◽  
pp. 7894
Author(s):  
Gabriela Neagu ◽  
Muhammet Berigel ◽  
Vladislava Lendzhova
Keyword(s):  
Data Analysis ◽  
Rural Areas ◽  
Secondary Data ◽  
Point Of View ◽  
Multidimensional Analysis ◽  
Theoretical Point ◽  
Digital Inclusion ◽  
Virtual Mobility ◽  
Alternative Research ◽  
High Share

This paper examines the perspectives of rural NEETs in the information society. Our analysis focuses on the situation of three European countries—Bulgaria, Romania, and Turkey—characterized by a high share of rural areas and a population of NEETs. From a methodological point of view, we use alternative research methods (secondary data analysis) with statistical methods (simple linear regression). From a theoretical point of view, we will opt for a multidimensional analysis perspective: the theory of digital divide, digital inclusion, virtual mobility, etc. Through data analysis, we expect to obtain a more complete and detailed picture of the ICT situation in rural areas (level of digital skills, level of digital inclusion) to demonstrate the importance of ICT in optimizing virtual mobility for the living conditions of the population, especially the NEET population.

scholarly journals Verbena officinalis Verbenaceae (Lamiales): a new plant model system for phyllotaxis research

2021 ◽  
Author(s):  
Beata Zagórska-Marek ◽  
Magdalena Turzańska ◽  
Klaudia Chmiel
Keyword(s):  
Vascular System ◽  
Cumulative Effect ◽  
Point Of View ◽  
Theoretical Point ◽  
Inflorescence Axis ◽  
Organ Identity ◽  
Lateral Organ ◽  
Complex Relationships ◽  
Secondary Transitions

AbstractPhyllotactic diversity and developmental transitions between phyllotactic patterns are not fully understood. The plants studied so far, such as Magnolia, Torreya or Abies, are not suitable for experimental work, and the most popular model plant, Arabidopsis thaliana, does not show sufficient phyllotactic variability. It has been found that in common verbena (Verbena officinalis L.), a perennial, cosmopolitan plant, phyllotaxis differs not only between growth phases in primary transitions but also along the indeterminate inflorescence axis in a series of multiple secondary transitions. The latter are no longer associated with the change in lateral organ identity, and the sequence of phyllotactic patterns is puzzling from a theoretical point of view. Data from the experiments in silico, confronted with empirical observations, suggest that secondary transitions might be triggered by the cumulative effect of fluctuations in the continuously decreasing bract primordia size. The most important finding is that the changes in the primary vascular system, associated with phyllotactic transitions, precede those taking place at the apical meristem. This raises the question of the role of the vascular system in determining primordia initiation sites, and possibly challenges the autonomy of the apex. The results of this study highlight the complex relationships between various systems that have to coordinate their growth and differentiation in the developing plant shoot. Common verbena emerges from this research as a plant that may become a new model suitable for further studies on the causes of phyllotactic transitions.

scholarly journals Modeling and theoretical description of magnetic hybrid materials—bridging from meso- to macro-scales

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Andreas M. Menzel ◽  
Hartmut Löwen
Keyword(s):  
Colloidal Particles ◽  
Colloidal Particle ◽  
Theoretical Description ◽  
Point Of View ◽  
Material Behavior ◽  
Theoretical Point ◽  
Mechanical Stiffness ◽  
Theoretical Approaches ◽  
Theoretical Predictions ◽  
Particle Level

Abstract Magnetic gels and elastomers consist of magnetic or magnetizable colloidal particles embedded in an elastic polymeric matrix. Outstanding properties of these materials comprise reversible changes in their mechanical stiffness or magnetostrictive distortions under the influence of external magnetic fields. To understand such types of overall material behavior from a theoretical point of view, it is essential to characterize the substances starting from the discrete colloidal particle level. It turns out that the macroscopic material response depends sensitively on the mesoscopic particle arrangement. We have utilized and developed several theoretical approaches to this end, allowing us both to reproduce experimental observations and to make theoretical predictions. Our hope is that both these paths help to further stimulate the interest in these fascinating materials.

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