1,720,962 research outputs found
Parallel Lattice Boltzmann code for simulating single phase flows in porous domains
No full textThis dataset contains a parallelized Lattice Boltzmann code, along with an example input domain and input file containing the necessary parameters for a test run. A MATLAB script to visualize and process the simulation results is also provided.
Among the uploaded files, Lb7mpi_281124.f90 is a computational code implementing a single phase Lattice Boltzmann (LB) model originally proposed by Guo et al. (2002). The code was developed by Prof. Andreas Yiotis (TUC) and Dr. Michael Kainourgiakis (NCSR Demokritos) based on the Fortran 95 computing language during 2005-2014. It is a highly parallel, scalable and computationally efficient code that relies on the MPI 2.0 (Message Passing Interface) protocol in order to take advantage of the computational capabilities of distributed memory supercomputers. As such, it has been thoroughly tested in terms of its efficiency and scalability in several large-scale supercomputers, including MareNostrum (BSC, Spain), IDRIS (France) and ARIS (Greece), exhibiting excellent scalability up to 2048+ cpu cores.
Lb7mpi is optimized for numerical simulations of single phase flows in 3D digital porous media in order to study the pore scale characteristics on the permeability of the digital porous domain. Flow is driven using a standard body force scheme and it is assumed to be periodic in all three directions in space. The digital domain is an ascii file that represents the 3D pore space as a sequence of 2D matrices. Each matrix corresponds to a fixed z value and contains the x-y conductivity of the medium. The hydraulic conductivity is denoted as zero (0) for solid lattice voxels where no flow is possible, and as one (1) for pore (void) voxels where flow takes place.
All computational parameters, including the name of the digital domain, the value of the body force, the LB relaxation parameters, as well as the load balancing scheme for parallel computation are declared by the user in a single input file named input.txt. The source code should be compiled using the standard mpif90 compiler wrapper that produces an executable linked to the installed mpi libraries available on your computational system.
The code is distributed as open-source and can be used explicitly for academic, educational and research purposes, as long as an appropriate reference to the original authors (see above) is provided. It should not be used as part of a commercial product. Furthermore, the code is distributed as is for the academic and research community without any warranty regarding the accuracy of the produced results. Very limited support can be provided by the authors. Such inquiries should be addressed to [email protected] (Prof. Andreas Yiotis)
Numerical investigation results of 3D porous structures using stochastic reconstruction algorithm
No full textThis dataset contains the outcomes of conducted numerical simulations, rooted in designs generated using a stochastic algorithm devised by Quiblie (1984), Adler et al. (1990), and Hyman et al. (2014).
Moreover, the investigation employed Lattice Boltzmann simulation, as used in previous study by Psihogios et al. (2007), where the simulations were focused on determining the permeability of the formulated domains. These domains encompassed a diverse array of porosities (0.15, 0.25, 0.35, and 0.45) and a range of correlation lengths (lambda : 15, 25, 35, and 45) that define pore size distributions. Additionally, to evaluate the influence of domain size, numerical simulations were carried out across a spectrum of domain sizes ranging from 100 to 700.
Furthermore, the numerical results derived from micro X-ray computed tomography scans of four micromodels (porosity : 0.45; lambda : 15, 25, 35, and 45) manufactured by additive manufacturing have also been incorporated within this dataset, for details cf. the realated dataset Ruf et al. (2023) and publication Lee et al. (2023)
Pore network modeling of convective drying
No full textDrying of porous media is a process of significant scientific and applied interest.
It involves several mechanisms at the pore scale that affect the macroscopic behavior
of the drying process. These include phase change at the liquid-gas interface, mass
and heat transfer by diffusion and convection, capillarity-induced flow through
wetting liquid films and the receding of the liquid gas interfaces under combined
viscous, capillary and buoyancy forces.
In most typical applications, porous materials are subjected to a flow of a purge gas
along the external porous surface, which can significantly enhance the recovery
process and reduce drying times. The local mass transfer coefficient depends on the
mass transfer conditions within the convective layer over the surface as well as on
the liquid saturation at the surface. For a realistic solution of the drying problem,
mass transfer in the convective layer needs to be solved in conjunction with mass
transfer within the porous medium.
This paper presents a coupled pore-network model that accomplishes such a solution.
The model accounts for isothermal evaporation at the liquid-gas interface, mass
transfer by diffusion and flow through liquid films within the porous medium and
convective mass transfer through the convective layer over the surface. We study the
effect of velocity profiles in the convective layer, the Peclet number of the purge
gas and the thickness of the convective layer on the drying curves. Our results show
that the drying rate remains practically constant as long as the liquid films span
along the pore network and their density at the surface is sufficiently high. Our
results explain previously reported experimental findings and provide a rigorous
explanation of the constant-rate period.Presenters:
name: Yiotis, Andreas
affiliation: NCSR 'Demokritos
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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