Wormhole dynamics, competition for the flow and changes in transport behavior: an intermediate-scale experiment

2021 ◽  
Author(s):  
Michela Trabucchi ◽  
Daniel Fernàndez-Garcia ◽  
Jesús Carrera
Keyword(s):  
Tracer Tests ◽  
Dissolution Experiment ◽  
Intermediate Scale ◽  
Geochemical Conditions ◽  
Flow Parameters ◽  
Salt Flats ◽  
Dissolved Species ◽  
Formation And Evolution ◽  
Scale Experiment ◽  
The One

<p>Salt flats (Salares) are complex evaporitic systems of economic interest and environmental value. On the one hand, these aquifers are usually exploited for variety of minerals, including dissolved species (e.g. Lithium and Potassium) extracted from the brines. On the other hand, the genesys of salares favors that they are surrounded by uncommon ecosystems, which must be protected. In this context, it is fear that brine pumping might favor the development of dissolution channels (Wormholes) that could connect the Salar nucleus with the environmental sensitive surroundings. Thus, a full understanding of the conditions and processes involved in wormhole formation and evolution has to be achieved. The hydraulic and geochemical conditions for conduits growth have been widely discussed in carbonate environments, while little has been done in halitic and gypsum environments. But we unknowledge experimental works aimed at understanding wormhole dynamics and the mechanism of competition for the flow that influence dissolution pattern evolution.</p><p>In this study, we want to improve the understanding of multiple wormholes growth in the context of wormhole competition and consequent changes in transport behaviors. For that purpose, we designed and performed a laboratory intermediate-scale tank experiment under controlled conditions. Halite in the form of granular medium is used to reproduce the aquifer. Hydrodynamics and geochemical conditions are set as to reproduce a dominant wormhole dissolution regime. Several coloured tracer tests are carried out to characterize the medium before, during and after the dissolution experiment.  Tracer concentration, hydrogeochemical and flow parameters, as well as tank images are continuously recorded. In particular, the use of fluorescent tracer jointly with image processing analysis highlights wormholes growth, shape and propagation through the medium at different times. Experimental results allow visualizing and analyzing several features related to wormhole competition, e.g. wormhole growth rate and density evolution, as well the redistribution of the flow towards areas where dominant wormholes are developing. Results are compared to available numerical and analytical solutions. Lastly, the interpretation of BTCs allows to understand changes in flow and trasport behavior and related processes, given the developing dissolution pattern.</p>

Numerical assessment on the performance of variable area single- and two-stage ejectors: A comparative study

2021 ◽  
pp. 095440892110331
Author(s):  
Anil Kumar ◽  
Virendra Kumar ◽  
PMV Subbarao ◽  
Surendra K Yadav ◽  
Gaurav Singhal
Keyword(s):  
Change Theory ◽  
Single Stage ◽  
Two Stage ◽  
Entrainment Ratio ◽  
Ansys Fluent ◽  
One Dimensional ◽  
Flow Parameters ◽  
Constant Rate ◽  
Numerical Assessment ◽  
The One

The two-stage ejector has been suggested to replace the single-stage ejector geometrical configuration better to utilize the discharge flow’s redundant momentum to induce secondary flow. In this study, the one-dimensional gas dynamic constant rate of momentum change theory has been utilized to model a two-stage ejector along with a single-stage ejector. The proposed theory has been utilized in the computation of geometry and flow parameters of both the ejectors. The commercial computational fluid dynamics tool ANSYS-Fluent 14.0 has been utilized to predict performance and visualize the flow. The performance in terms of entrainment ratio has been compared under on- design and off-design conditions. The result shows that the two-stage ejector configuration has improved (≈57%) entrainment capacity than the single-stage ejector under the on-design condition.

scholarly journals Full exploration of the giant planet population around β Pictoris

2018 ◽  
Vol 612 ◽  
pp. A108 ◽  
Author(s):  
A.-M. Lagrange ◽  
M. Keppler ◽  
N. Meunier ◽  
J. Lannier ◽  
H. Beust ◽  
...  
Keyword(s):  
Extrasolar Planets ◽  
Giant Planet ◽  
Young Stars ◽  
Giant Planets ◽  
Close Orbit ◽  
Wide Range ◽  
Detection Probabilities ◽  
Solar Type ◽  
Formation And Evolution ◽  
The One

Context. The search for extrasolar planets has been limited so far to close orbit (typ. ≤5 au) planets around mature solar-type stars on the one hand, and to planets on wide orbits (≥10 au) around young stars on the other hand. To get a better view of the full giant planet population, we have started a survey to search for giant planets around a sample of carefully selected young stars. Aims. This paper aims at exploring the giant planet population around one of our targets, β Pictoris, over a wide range of separations. With a disk and a planet already known, the β Pictoris system is indeed a very precious system for studies of planetary formation and evolution, as well as of planet–disk interactions. Methods. We analyse more than 2000 HARPS high-resolution spectra taken over 13 years as well as NaCo images recorded between 2003 and 2016. We combine these data to compute the detection probabilities of planets throughout the disk, from a fraction of au to a few dozen au. Results. We exclude the presence of planets more massive than 3 MJup closer than 1 au and further than 10 au, with a 90% probability. 15+ MJup companions are excluded throughout the disk except between 3 and 5 au with a 90% probability. In this region, we exclude companions with masses larger than 18 (resp. 30) MJup with probabilities of 60 (resp. 90) %.

FORMATION OF THE GENRE OF THE STORY IN THE CHERKESS LITERATURE: IDELOGICAL GUIDES AND THEMATIC REFERENCES

Kavkazologiya ◽  
2021 ◽  
pp. 219-288
Author(s):  
M.A. KHAKUASHEVA ◽  
◽  
L.B. KHAVZHOKOVA ◽  
Keyword(s):  
The Other ◽  
North Caucasus ◽  
Research Attention ◽  
The North ◽  
Initial Stage ◽  
Great Patriotic War ◽  
History Of ◽  
Formation And Evolution ◽  
The One ◽  
Artistic Analysis

The article examines some of the issues of the formation and evolution of the genre of the story in Circassian literature. The relevance of the study is due, on the one hand, to the insufficient development of the stated topic, on the other hand, to the need to identify trends in the development of national prose, starting from the problems of its genesis. In the center of research attention is the ideological and thematic orientation of the Circassian story mainly of the initial stage of evolution, i.e. Soviet era. In particular, the author examines the stories of S. Temirov, I. Amirokov, M. Adamokov, H. Gashokov and others, who laid the foundations of the genre in Circassian literature. During the indicated period, the Circassian tale was the first attempt to comprehend the problems of collective farms, youth brigades, the Soviet attitude to work, the range of urgent problems of young people, their aspirations, the formation of the criteria of Soviet morality. It also reflects various aspects of the Great Patriotic War, mainly as a war for independence. The research uses the method of artistic analysis. The results obtained can be used in compiling special courses on Adyghe (Kabardino-Circassian) prose, writing the history of the literature of the peoples of the North Caucasus.

A New Approach to The Design of Fan Volute Profiles

1996 ◽  
Vol 210 (3) ◽  
pp. 287-294 ◽  
Author(s):  
D T Qi ◽  
M J Pomfret ◽  
K Lam
Keyword(s):  
Design Method ◽  
Operating Conditions ◽  
Flow Angle ◽  
New Approach ◽  
One Dimensional ◽  
Distribution Form ◽  
Flow Parameters ◽  
Centrifugal Fans ◽  
Ultimate Objective ◽  
The One

In traditional volute design methods, the flow at the volute inlet is assumed to be uniform according to one-dimensional theory. However, many experimental results have shown that under the design operating conditions, the actual distributions of the flow parameters at the volute inlet are different from those predicted by the ideal assumption. This is because of the influence of the non-axisymmetrical volute geometry, especially due to the presence of the volute tongue. Based on this fact, a new method was considered whereby different volute profiles can be generated by varying the distributions of flow parameters at the volute inlet. The ultimate objective is to achieve the optimal volute profile design so that the performance of a centrifugal machine can be improved. In this paper, a two-dimensional inverse method has been used to redesign the original volute profiles of two centrifugal fans. The results show that the method presented provides effective improvement to the one-dimensional volute design method. The controlled distribution form of volute inlet flow angle α4 in the redesign is qualitatively discussed and can be used for reference in the volute design and further research.

scholarly journals Direct Drive Wave Energy Buoy ? Intermediate scale experiment

2013 ◽  
Author(s):  
Kenneth E. Rhinefrank ◽  
Pukha Lenee-Bluhm ◽  
Joseph H. Prudell ◽  
Alphonse A. Schacher ◽  
Erik J. Hammagren ◽  
...  
Keyword(s):  
Wave Energy ◽  
Direct Drive ◽  
Intermediate Scale ◽  
Scale Experiment

scholarly journals The effect of warm gas on the buckling instability in galactic bars

2020 ◽  
Vol 634 ◽  
pp. A122
Author(s):  
Ewa L. Łokas
Keyword(s):  
Dark Matter ◽  
Milky Way ◽  
Gas Content ◽  
Dark Matter Halo ◽  
Buckling Instability ◽  
Radial Profiles ◽  
Formation And Evolution ◽  
The One ◽  
Gas Fractions ◽  
Gas Component

By using N-body and hydro simulations, we study the formation and evolution of bars in galaxies with significant gas content focusing on the phenomenon of the buckling instability. The galaxies are initially composed of a spherical dark matter halo and only stellar, or stellar and gaseous, disks with parameters that are similar to the Milky Way and are evolved for 10 Gyr. We consider different values of the gas fraction f = 0−0.3 and in order to isolate the effect of the gas, we kept the fraction constant during the evolution by not allowing the gas to cool and form stars. The stellar bars that form in simulations with higher gas fractions are weaker and shorter, and they do not form at all for gas fractions that are higher than 0.3. The bar with a gas fraction of 0.1 forms sooner due to initial perturbations in the gas, but despite the longer evolution, it does not become stronger than the one in the collisionless case at the end of evolution. The bars in the gas component are weaker; they reach their maximum strength around 4 Gyr and later decline to transform into spheroidal shapes. The distortion of the stellar bar during the buckling instability is weaker for higher gas fractions and weakens the bar less significantly, but it has a similar structure both in terms of radial profiles and in face-on projections. For f = 0.2, the first buckling lasts significantly longer and the bar does not undergo the secondary buckling event, while for f = 0.3, the buckling does not occur. Despite these differences, all bars develop boxy/peanut shapes in the stellar and gas component by the end of the evolution, although their thickness is smaller for higher gas fractions.

The Radial Equilibrium Problem of Flow in Wave Machinery

1993 ◽  
Vol 207 (1) ◽  
pp. 23-30 ◽  
Author(s):  
Gao-Lian Liu
Keyword(s):  
Equilibrium Problem ◽  
Gas Flow ◽  
Design Procedure ◽  
Salient Feature ◽  
Flow Parameters ◽  
Method Of Solution ◽  
Outlet Flow ◽  
And Performance ◽  
The One ◽  
Radial Equilibrium

The present paper deals with the radial equilibrium problem of gas flow at the inlet and outlet of a wave rotor theoretically, presenting a method of solution. The salient feature of this method is that, in contrast to turbomachinery, the outlet flow parameters are related to those at inlet by the state characteristic (compatibility) equations of unsteady rotor flow. The numerical example has shown that the radial equilibrium effect plays a very important role in the design and performance of wave machinery and hence it is suggested that a complete gas dynamic design procedure of a wave machine should include two parts: (a) solution of the one-dimensional unsteady relative flow in rotor at the mean radius; (b) solution of the radial equilibrium problem of gas flow at the rotor inlet and outlet.

Modeling trichloroethene reduction in a hydrogen-based biofilm

2013 ◽  
Vol 68 (5) ◽  
pp. 1158-1163 ◽  
Author(s):  
Youneng Tang ◽  
Rosa Krajmalnik-Brown ◽  
Bruce E. Rittmann
Keyword(s):  
Extracellular Polymeric Substances ◽  
Complete Removal ◽  
Denitrifying Bacteria ◽  
Biofilm Reactor ◽  
Reductive Dehalogenation ◽  
Monod Kinetics ◽  
Membrane Biofilm Reactor ◽  
Scale Experiment ◽  
The One ◽  
Dissolved Components

We constructed a multispecies biofilm model for simultaneous reduction of trichloroethene (TCE) and nitrate (NO3−) in the biofilm of a H2-based membrane biofilm reactor (MBfR). The one-dimensional model includes dual-substrate Monod kinetics for a steady-state biofilm with multiple solid and dissolved components. The model has five solid components: autotrophic denitrifying bacteria (ADB), heterotrophic denitrifying bacteria (HDB), Dehalococcoides (DHC), inert biomass (IB), and extracellular polymeric substances (EPS). The model has eight dissolved components: NO3−, TCE, dichloroethene (DCE), vinyl chloride (VC), ethene, hydrogen (H2), substrate-utilization-associated products (UAP), and biomass-associated products (BAP). We used this model to simulate a bench-scale experiment in a H2-based MBfR. The model simulated the trends well: almost complete removal of nitrate, incomplete reduction of TCE, and almost no accumulation of DCE and VC. To gain insight into reductive dehalogenation in a H2-based MBfR, we also simulated the concentrations of nitrate, TCE, DCE, VC, and ethene in the reactor effluent while varying the influent nitrate concentration. Simultaneous low concentrations of nitrate and the three chlorinated ethenes can occur as long as the influent ratio of NO3− to TCE is not too large, so that DHC are a significant fraction of the biofilm.

scholarly journals Las salinas en la Cartografía. Construcción del territorio y del paisaje Salt flats on mapping = Building territories and landscapes

2020 ◽  
pp. 24
Author(s):  
Pilar Chías Navarro ◽  
Tomás Abad Balboa
Keyword(s):  
Information System ◽  
Historical Memory ◽  
Point Of View ◽  
The Other ◽  
Salt Flats ◽  
Main Target ◽  
Dual Perspective ◽  
Double Approach ◽  
The One ◽  
Sistemas De Informacion

RESUMEN:Las salinas conforman territorios de características singulares y paisajes de especial encanto. Su estudio implica efectuar una doble aproximación: desde un punto de vista objetivo, que considera los elementos y fenómenos que tienen lugar en un determinado ámbito geográfico; y también subjetivo, que valora las cualidades que percibe o experimenta ante él un observador. Nuestro objetivo es recuperar la memoria de los territorios y los paisajes sobre la base de esta doble perspectiva, y elaborar series cartográficas que sirvan de base a sistemas de información geográfica patrimonial. Para ello resulta esencial combinar una exhaustiva búsqueda en archivo con un intenso trabajo de campo. El resultado permite conocer la existencia pretérita de elementos naturales y construidos, así como de usos y costumbres perdidos que durante una época existieron sobre un territorio concreto y conformaron unos paisajes singulares. Entre el material de archivo, las imágenes, los mapas y los planos realizados antes y después del desarrollo de la cartografía científica resultan de particular interés como fuentes de datos, aunque su interpretación requiere contar con conocimientos especializados. Asimismo, las manifestaciones artísticas tienen gran valor para conocer cómo se han experimentado unos paisajes que son el resultado de las culturas sucesivas que los conformaron. El artículo se centra en esta parte esencial de la metodología.ABSTRACT:Salt flats use to shape territories characterized by particular features, and particularly charming landscapes. Their study implies a double approach. On the one hand, an objective point of view considers every element and phenomenon that take place on a given area. On the other hand, a subjective perspective allows to assess all the spatial qualities that are perceived or experienced by the observer. Our main target aims to recover the historical memory of territories and landscapes, on the grounds of such a dual perspective. But also, to produce the corresponding cartographic series that will provide the digital basis for a geographic information system focused on the cultural heritage. For this purpose, it becomes essential to develop an exhaustive archival search, as well as an intensive fieldwork. They will permit to get a deep knowledge of every natural or built element in the area, together with the old uses and habits that shaped the current territories and landscapes. Among the historic sources, old pictures, and ancient or scientific maps should be stressed, due to their interest as essential sources of geographic data. However, they must be carefully read, what requires a specialised knowledge. Similarly, the artistic expressions are of great interest because of their ability to show the experience of a landscape as a result of an overlapping of cultures. The article focuses in such aspects of a global methodology.

scholarly journals Galaxy morphology prediction using Capsule Networks

2019 ◽  
Vol 486 (2) ◽  
pp. 1539-1547 ◽  
Author(s):  
Reza Katebi ◽  
Yadi Zhou ◽  
Ryan Chornock ◽  
Razvan Bunescu
Keyword(s):  
Network Architecture ◽  
Critical Role ◽  
Neural Network Architecture ◽  
Sky Surveys ◽  
The Galaxy ◽  
Formation And Evolution ◽  
The One ◽  
Rotationally Invariant ◽  
Key Parameter ◽  
Galaxy Morphology

Abstract Understanding morphological types of galaxies is a key parameter for studying their formation and evolution. Neural networks that have been used previously for galaxy morphology classification have some disadvantages, such as not being inherently invariant under rotation. In this work, we studied the performance of Capsule Network (CapsNet), a recently introduced neural network architecture that is rotationally invariant and spatially aware, on the task of galaxy morphology classification. We designed two evaluation scenarios based on the answers from the question tree in the Galaxy Zoo project. In the first scenario, we used CapsNet for regression and predicted probabilities for all of the questions. In the second scenario, we chose the answer to the first morphology question that had the highest user agreement as the class of the object and trained a CapsNet classifier, where we also reconstructed galaxy images. We achieved promising results in both of these scenarios. Automated approaches such as the one introduced here will play a critical role in the upcoming large sky surveys.

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