Annulus (botany)

Abstract: An annuloplasty ring for correcting maladies of the mitral annulus that not only reshapes the annulus but also reconfigures the adjacent left ventricular muscle wall The ring may be continuous and is made of a relatively rigid material, such as Stellite The ring has a generally oval shape that is three-dimensional at least on the posterior side A posterior portion of the ring rises or bows upward from adjacent sides to pull the posterior aspect of the native annulus farther up than its original, healthy shape In doing so, the ring also pulls the ventricular wall upward which helps mitigate some of the effects of congestive heart failure Further, one or both of the posterior and anterior portions of the ring may also bow inward

Abstract: A method and apparatus for fracturing a formation or gravel packing a borehole extending through an unconsolidated subterranean zone in a formation includes a screen assembly having a length adapted for disposal adjacent the unconsolidated subterranean zone and includes a plurality of screens mounted on a base member with adjacent base members being connected by a sub having an aperture in the wall thereof A flow-control service assembly is disposed within the bore of the screen assembly and includes an outer tubular member and an inner tubular member The outer tubular member includes a plurality of ports that communicate with the apertures in the screen assembly The apertures in the screen assembly are disposed along the length of screen assembly at predetermined intervals The inner tubular member and outer tubular member form an inner annulus, the outer tubular member and screen assembly form a medial annulus, and the screen assembly forms an outer annulus with the wall of the borehole Barriers are placed around the ports on the outer tubular member to prevent the formation of gravel bridges across the inner annulus The inner annulus provides alternative flow paths around the ports upon the ports becoming closed to fluid flow such as by bridges In operation, fluids, such as fracing fluids or a gravel slurry, is pumped down the inner annulus, through the ports in the outer tubular member and apertures in the screen assembly and into the outer annulus prior to passing through the perforations into the formation Return fluid may pass through the screens, through the medial annulus and into the flowbore of the inner tubular member to flow to the surface The fluid flowing through the inner annulus passes through the ports and apertures into the outer annulus substantially uniformly along the length of the screen assembly thereby creating fractures uniformly along the unconsolidated subterranean zone from top to bottom

Abstract: The current study uses the multi-physics COMSOL software and the Darcy–Brinkman–Forchheimer model with a porosity of ε = 0.4 to conduct a numerical study on heat transfer by Cu-TiO2/EG hybrid nano-fluid inside a porous annulus between a zigzagged triangle and different cylinders and under the influence of an inclined magnetic field. The effect of numerous factors is detailed, including Rayleigh number (103 ≤ Ra ≤ 106), Hartmann number (0 ≤ Ha ≤ 100), volume percent of the nano-fluid (0.02 ≤ ϕ ≤ 0.08), and the rotating speed of the cylinder (−4000 ≤ w ≤ 4000). Except for the Hartmann number, which decelerates the flow rate, each of these parameters has a positive impact on the thermal transmission rate.