Ramesh A.,University of Illinois at Urbana - Champaign |
Akram W.,University of Illinois at Urbana - Champaign |
Mishra S.P.,University of Illinois at Urbana - Champaign |
Cannon A.H.,Hoowaki LLC |
And 2 more authors.
Tribology International | Year: 2013
We report experimental and numerical investigations of the friction characteristics of microtextured surfaces. The textures are of size 28-257 μm on stainless steel surfaces, fabricated using micro-casting. Friction characteristics of these surfaces were tested under submerged conditions using a pin-on-disk configuration. Numerical simulations solved the Navier-Stokes equations to predict the texture-induced lift. During hydrodynamic lubricated sliding, the textured surfaces exhibit friction as much as 80% lower than the untextured surfaces. We study the effect of operating conditions on the friction performance of the surfaces for different textures. The trends obtained in the experiments match well with the simulations, and indicate design rules for the implementation of this technology. © 2012 Elsevier Ltd.
Hoowaki LLC | Date: 2010-06-11
Described herein are casting and molding methods useful for making microstructured objects. By including a plurality of microfeatures on the surface of an object, other characteristics may be imparted to the object, such as increased hydrophobicity. Some of the casting and molding methods described herein further allow for manufacture of objects having both microfeatures and macro features, for example microfeatures on or within macro features or selected macro feature regions.
Hoowaki LLC | Date: 2015-04-21
This invention is a fracturing component and method having a fluid and a plurality of three dimensional structures mixed in the fluid wherein each structure has a longitudinal axis, center of mass and center of pressure wherein the center of mass and the center of pressure do not align in a stable manner causing the structure to flutter in the fluid to reduce the structure from settling out of the fluid when injected into a fissure. Each three dimensional structure can include a first end of the structure having a first plane having an angle of incident
Hoowaki Llc | Date: 2015-06-22
This invention is directed to an improved contact surface for manipulating fabrics wherein the microstructure included on the contact surface having a plurality of pillars spaced apart in the range of 200 m and 600 m, having a height in the range of 50 m and 1200 m, a width of in the range of 70 m and 300 m, a wall draft angle between 0 and 15, a density of in the range of 5,000 to 20,000 pillars per square inch, and a friction rating greater than 7. The contact surface can be included on a sewing machine feed dog, a glove, sporting equipment, firearm grip, hand rail, tools, and a strap such as for a satchel or backpack.
Hoowaki Llc | Date: 2015-06-30
A manufacturing apparatus for manufacturing extruded parts having microstructures comprising: a support structure; a hopper carried by the support structure for receiving feedstock; an extrusion chamber operatively associated with the hopper for receiving the feedstock from the hopper and melting the feedstock above a feedstock melting temperature; a die carried by the support structure having die microstructures disposed on an inner surface of the die, the die microstructures having a plurality of microfeatures each having an upper surface and a lower surface, the melted feedstock being forced through the die to produce an extrudate having extrudate microstructures; and, a cooling assembly wherein the extrudate microstructures of the pre-cooled extrudate have larger physical dimensions than that of the extrudate microstructures of the cooled extrudate.