7 research outputs found
Obstacle-induced lateral dispersion and nontrivial trapping of flexible fibers settling in a viscous fluid
Full text linkThe motion of flexible fibers through structured fluidic environments is
ubiquitous in nature and industrial applications. Most often, their dynamics
results from the complex interplay between internal elastic stresses, contact
forces and hydrodynamic interactions with the walls and obstacles. By means of
numerical simulations, experiments and analytical predictions, we investigate
the dynamics of flexible fibers settling in a viscous fluid embedded with
obstacles of arbitrary shapes. We identify and characterize two types of
events: trapping and gliding, for which we detail the mechanisms at play. We
observe nontrivial trapping conformations on sharp obstacles that result from a
subtle balance between elasticity, gravity and friction. In the gliding case, a
flexible fiber reorients and drifts sideways after sliding along the obstacle.
The subsequent lateral displacement is large compared to the fiber length and
strongly depends on its mechanical and geometrical properties. We show how
these effects can be leveraged to propose a new strategy to sort particles
based on their size and/or elasticity. This approach has the major advantage of
being simple to implement and fully passive, since no energy is needed.Comment: 18 pages, 9 figure
Obstacle-induced lateral dispersion and nontrivial trapping of flexible fibers settling in a viscous fluid
No full text18 pages, 9 figuresThe motion of flexible fibers through structured fluidic environments is ubiquitous in nature and industrial applications. Most often, their dynamics results from the complex interplay between internal elastic stresses, contact forces and hydrodynamic interactions with the walls and obstacles. By means of numerical simulations, experiments and analytical predictions, we investigate the dynamics of flexible fibers settling in a viscous fluid embedded with obstacles of arbitrary shapes. We identify and characterize two types of events: trapping and gliding, for which we detail the mechanisms at play. We observe nontrivial trapping conformations on sharp obstacles that result from a subtle balance between elasticity, gravity and friction. In the gliding case, a flexible fiber reorients and drifts sideways after sliding along the obstacle. The subsequent lateral displacement is large compared to the fiber length and strongly depends on its mechanical and geometrical properties. We show how these effects can be leveraged to propose a new strategy to sort particles based on their size and/or elasticity. This approach has the major advantage of being simple to implement and fully passive, since no energy is needed
Obstacle-induced lateral dispersion and nontrivial trapping of flexible fibers settling in a viscous fluid
No full text18 pages, 9 figuresThe motion of flexible fibers through structured fluidic environments is ubiquitous in nature and industrial applications. Most often, their dynamics results from the complex interplay between internal elastic stresses, contact forces and hydrodynamic interactions with the walls and obstacles. By means of numerical simulations, experiments and analytical predictions, we investigate the dynamics of flexible fibers settling in a viscous fluid embedded with obstacles of arbitrary shapes. We identify and characterize two types of events: trapping and gliding, for which we detail the mechanisms at play. We observe nontrivial trapping conformations on sharp obstacles that result from a subtle balance between elasticity, gravity and friction. In the gliding case, a flexible fiber reorients and drifts sideways after sliding along the obstacle. The subsequent lateral displacement is large compared to the fiber length and strongly depends on its mechanical and geometrical properties. We show how these effects can be leveraged to propose a new strategy to sort particles based on their size and/or elasticity. This approach has the major advantage of being simple to implement and fully passive, since no energy is needed
Isolation, biochemical and molecular identification and investigation of probiotic potential of chicken intestine Bifidobacteria in rural areas of Ardabil province
No full textBackground and Objective: More than a century after discovering probiotic strains, the food and dairy industries are increasingly looking to improve their products with these beneficial bacteria. This study aimed to analyze the potential characteristics of Iranian native probiotics and evaluate the safety of native probiotic Bifidobacterium isolated from the intestines of local chickens to discover the production potential of additives for food and dairy industries and feed.
Materials and Methods: After sampling and preparing serial dilution, the samples were identified using biochemical tests. To confirm probiotics, growth ability was performed at different pHs, dilutions of bile salts and NaCl, isolated antimicrobial activity against common pathogens, and antibiotics susceptibility. Finally, the optimal strains were identified by molecular methods.
Results: Four strains of the 15 gram-positive catalase-negative strains were biochemically similar to Bifidobacterium. Themes grew at PH 3-9 and different concentrations of bile salt and NaCl. These bacteria also had antimicrobial activity against common pathogens and were resistant to many antibiotics. Strains E1 and E4 had better probiotic properties. Finally, the molecular test showed that strains E1 and E4 were 100% similar to Bifidobacterium animalis and Bifidobacterium langum, respectively.
Conclusions: The intestines of local chickens in Ardabil province contain probiotic bacteria such as Bifidobacterium animalis and Bifidobacterium langum. Therefore, these bacteria can be used in the food and dairy industries and improve livestock and poultry fee
