1,720,990 research outputs found
Lattice Boltzmann modelling of bacterial colony patterns
Full text linkThe formation of branches in bacterial colonies is influenced by both chemical interactions (reactions) and the movement of substances through space (diffusion). These colonies can exhibit a variety of fascinating branching patterns due to the interplay of nutrient transport, bacterial growth, and chemotaxis. To understand this complex process, researchers have developed several mathematical models based on solving reaction-diffusion equations. In this letter, we introduce an innovative application of the lattice Boltzmann method to investigate the diverse morphological patterns observed in bacterial colonies. This method is concise, compact, and easy to implement. Our study demonstrates its effectiveness in accurately predicting various types of bacterial colony patterns, offering a new tool to obtain insights into the dynamics of bacterial growth andpattern formation
UMAT routines for Abaqus CAE
No full textYoutube link to video: https://www.youtube.com/watch?v=-uZH1F4QX2M
Abstract of the lecture
Dr. Jha will present a methodology for the development of UMAT in Abaqus CAE. In this regard, the lecture will focus on modeling of the damage in hyperelastic materials. In addition, the lecture will also demonstrate the development of UMAT as well. Over the course of the lecture, he will present theoretical formulations followed by code review. The intended audience of this lecture is Master / Ph.D. / Industry participants who are beginning to use UEL routines in Abaqus CAE
Pointwise contact numerical models and applications
No full textYoutube link to the video: https://www.youtube.com/watch?v=3VpkVH2osxk
Abstract of the lecture
In this lecture, an overview of computational modeling of pointwise contact will be given. Beam-to-beam contact will be addressed, such as contact involving rigid/flexible bodies, modeled by beams/shells. An overview of the master-master contact strategy will be provided, presenting its pros/cons, such as numerous examples.
Related publications
Gay Neto, A.; Wriggers, P.; Master-master frictional contact and applications for beam-shell interaction. Computational Mechanics, Published Online, 2020.
Gay Neto, A.; Wriggers, P.; Numerical method for solution of pointwise contact between surfaces. Computer Methods in Applied Mechanics and Engineering, v. 365,112971, 2020.
Gay Neto, A.; Wriggers, P.; Computing pointwise contact between bodies: a class of formulations based on master-master approach. Computational Mechanics, Published Online, 2019.
Campos, P.R.R.; Gay Neto, A.; Rigid body formulation in a finite element context with contact interaction. Computational Mechanics, 62:1369, 2018.
Gay Neto, A.; Pimenta, P. M.; Wriggers, P.; Contact between spheres and general surfaces. Computer Methods in Applied Mechanics and Engineering, v. 328, p. 686-716, 2018.
Gay Neto, A.; Campello, E. M. B.; Granular materials interacting with thin flexible rods. Computational Particle Mechanics, v. 4, p. 229-247, 2017.
Gay Neto, A.; Pimento, P. M.; Wriggers, P.; A master-surface to master-surface formulation for beam to beam contact. Part II: Frictional interaction. Computer 8. Methods in Applied Mechanics and Engineering, v. 319, p. 146-174, 2017.
Gay Neto, A.; Simulation of mechanisms modeled by geometrically-exact beams using Rodrigues rotation parameters. Computational Mechanics, v. 59, p. 459-481, 2017.
Gay Neto, A.; Pimento, P. M.; Wriggers, P.; A master-surface to master-surface formulation for beam to beam contact. Part I: Frictionless interaction. Computer Methods in Applied Mechanics and Engineering, v. 303, p. 400–429, 2016
Machine intelligence in mechanical and aerospace sciences: Today & beyond
No full textIn this lecture, the application of AI / ML and the upcoming trends are discussed, particularly in reference to mechanical and aerospace industries. AI and ML have been topics of huge interest in recent times. Machine learning techniques are being applied vastly to understand the uncertainties in the models - both solid and fluid mechanics. During the lecture, we will discuss on how artificial intelligence is being used in the aerospace industry
Chaotic footprints of a flapping wing: A computational perspective
No full textThe lecture will discuss the investigations made on the complex vortex interactions in a flapping wing. The flow-field transitions from periodic to chaotic through a quasi-periodic route as the plunge amplitude is gradually increased. This study unravels the role of the complex interactions that take place among the main vortex structures in making the unsteady flow-field transition from periodicity to chaos.
The lecture is available for viewing through youtube at: https://www.youtube.com/watch?v=aQZxxe8YUR
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
Dynamics Of The Spatio-Temporal Wave-Front As Unique Precursor Of Flow Transition
No full textYoutube link to the video: https://www.youtube.com/watch?v=3qw_VucKTZI
Abstract of the lecture
Regardless of numerous theoretical, numerical and experimental efforts, several aspects of laminar to turbulent transition in fluid flows still remain ambiguous. One way of studying the flow transition is by treating it as a dynamical system where transition is caused by amplification of instability waves, which are mathematically, posed as the eigen-solution of the linearized governing equations describing evolution of small disturbances over the base flow. Instability waves are triggered inside the boundary layer by natural or imposed external perturbations through a process known as receptivity, a term receptivity first coined by Morkovin (Springer, 1993). Conventionally flow instability is studied by treating it either as temporal or spatial problem disregarding the spatio-temporal evolution of physical disturbances. Linearized spatio-temporal analysis of incompressible boundary layer by Bromwich contour integral method predicted the existence of the spatio-temporal wave-packet (STWP) (Sengupta et al. Phys. Rev. Lett., 96, 2006), which exhibits growth even for flows, which are stable following linearized stability analysis. Subsequently, the STWP has been established as the prime-mover for flow transition by high-accuracy direct numerical simulation (DNS) of the receptivity of the low-speed incompressible flows [1-6] to monochromatic definitive wall-excitation (started impulsively or gradually). These showed how STWP triggers flow transition and generation of turbulent spots, which later merge together to create fully developed turbulent flow. 3D receptivity results reported in [5,6] showed that both K- and H- route of flow transition can be induces by the growth of STWP due to single monochromatic excitation frequency.
Related publications
T. K. Sengupta, S. Bhaumik, Onset of turbulence from the receptivity stage of fluid flows, Physical Review Letters 107(15) (2011) 154501.
T. K. Sengupta, S. Bhaumik, Y. G. Bhumkar, Direct numerical simulation of two-dimensional wall-bounded turbulent flows from receptivity stage, Physical Review E 85(2) (2012) 026308.
S. Bhaumik, T. K. Sengupta, Precursor of transition to turbulence: Spatiotemporal wave front, Physical Review E 89(4) (2014) 043018.
S. Bhaumik, T. K. Sengupta, A new velocity-vorticity formulation for direct numerical simulation of 3D transitional and turbulent flows, Journal of Computational Physics 284 (2015) 230–260.
P. Sharma, T. K. Sengupta, S. Bhaumik, Three-dimensional transition of zero-pressure-gradient boundary layer by impulsively and nonimpulsively started harmonic wall excitation, Physical Review E 98 (2018) 053106.
S. Bhaumik, T. K. Sengupta, Z. A. Shabab, Receptivity to harmonic excitation following nonimpulsive start for boundary-layer flows, AIAA Journal (2017) 3233–3238
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
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