Abstract:
New fluid separation devices and absorption materials are disclosed. Hollow fibers with an axial capillary slit act as very high efficiency absorption materials, as well as high-surface-area fluid separation devices. The hollow fibers with an axial capillary slit are constructed to preferentially absorb or repel different fluids and arranged to maximize that action over a plurality of fibers to separate different fluids. These separation devices can also function as injection devices and very effective micro-reactors.
Abstract:
A liquid to solid material surface contact angle measurement system operating by way of detecting a transition in the behavior of a liquid sample with the solid material in a changing angular confinement environment along with use of a mathematical algorithm to then determine contact angle. Measurement of the angle at which the tested liquid transitions between apparent wetting and apparent non-wetting behavior, regardless of whether the liquid and solid material are truly classified as wetting or non-wetting, provides a measurement from which disclosed mathematical algorithms can predict the surface wetting characteristics of the liquid on the solid material. Automated performance of the confinement environment measurement and examples are included.
Abstract:
There are provided methods for fabricating baby bottle nipples which mimic the function of the human breast nipple. In the human breast nipple, milk is delivered to the baby through 15-25 fluid-delivery capillaries called lactiferous ducts. These ducts are 2-4 centimeters in length and 500-900 microns in diameter. Baby bottle nipples fabricated in accordance with the methods of this invention have the common feature of at least one hydrophilic fluid delivery passage. In one embodiment, the fluid delivery passage is a microtube. In another embodiment, the fluid delivery passage is a microchannel. In yet another embodiment, the fluid delivery passage comprises a porous reticulated foam with interconnected pores. In each of these embodiments, the fluid delivery passage has at least one dimension in the range of 1-2000 microns.
Abstract:
In the present invention, a technique is described for manufacturing microtube devices which have peripheral geometries that are not uniform along the tube or device axis. These geometries may exist in only one location on the periphery of the microtube device or geometries may be repeated either uniformly or non-uniformly with micron or sub-micron precision along the tube or device axis. The preferred manufacturing process involves forming a complex mandrel, ie., (one, for example, that can not be formed by extrusion or pultrusion under constant processing conditions) and giving it at least one metallic and/or nonmetallic coating by any of a variety of techniques. The complex mandrel can then be removed by appropriate chemical or physical means that do not adversely affect the coating(s) desired for the wall. The result is a microtube structure having an axial profile duplicating that on the mandrel from which it was formed.
Abstract:
This invention is a rapid low-cost technique for manufacturing thick high-performance carbon and ceramic composites in the form of uniformly densified near-net shaped structures. This is accomplished by impregnating composite preforms with low-viscosity wetting monomers which undergo polymerization followed by pyrolysis reactions in the preform ultimately creating ceramic and/or carbon matrices. Since the monomers possess low-molecular-weight they have low viscosities. Thus, if they wet the fiber and partially-densified preform they can easily impregnate even the smallest pores. Once inside the preforms, polymerization of the monomers is then initiated, resulting in a liquid matrix-precursor of the high molecular weight needed to produce a superior matrix (upon pyrolysis) with high efficiency.
Abstract:
The present invention is a technique for manufacturing microtube devices which have circumferential geometries repeated either uniformly or nonuniformly along the tube or device axis with sub-micron precision. The preferred manufacturing process involves forming a complex mandrel and giving it a metallic and/or nonmetallic coating or coatings by any of a variety of techniques. The mandrel can then be removed by appropriate chemical or physical means, leaving a microtube structure having an axial profile consisting of repeat units duplicating those on the mandrel. One technique for forming the complex mandrel consists of drawing a single core fiber (or bundle of core fibers) through a confining orifice. The fiber is held with minimal constraint (typically by friction), so that no breakage takes place as it is drawn through the orifice. However, enough constraint exists so that torque applied tangentially by another overwrapping fiber (or fibers) as it is being wound around the core fiber does not cause the core fiber to slip in the direction of applied torque. Moreover, the overwrapping fiber must be wound sufficiently close to the constraining orifice that twisting of the core fiber in the direction of torque is minimized to such an extent that unwinding, or "backlash" does not occur when constraining forces are removed at the end of winding.
Abstract:
In the present invention, various sizes of non-wetting droplets are inserted into microtube devices of various shapes having therein a gas or wetting fluid which causes the droplets to movement in response to fluid pressure. The droplets may translate within a void of the microtube device which is filled with the gas or wetting fluid or rotate in a fixed position. The nonwetting fluid may also be formed into rings within ring shaped channels. The microtube devices may operate to stop fluid flow, act as a check-valve, act as a flow restrictor, act as a flow regulator, act as a support for a turning axle, and act as a logic device, for example.
Abstract:
Provided are methods for fabricating fluid separation devices with precisely-sized, shaped microscopic capillaries that can separate one immiscible fluid from another on the basis of different separation characteristics. In particular, the method comprises the steps of fabricating a first set of capillaries having a first separation characteristic and a second set of capillaries having a second separation characteristic, incorporating one end of all of the capillaries into an inlet face, incorporating the second end of the first set of capillaries into a first outlet face, and incorporating the second end of the second set of capillaries into a second outlet face. Preferably, the first set of capillaries is hydrophillic and the second set of capillaries is hydrophobic.
Abstract:
Baby bottle nipples which mimic the function of the human breast nipple are provided. In the human breast nipple, milk is delivered to the baby through 15-25 fluid-delivery capillaries called lactiferous ducts. These ducts are 2-4 centimeters in length and 500-900 microns in diameter. Baby bottle nipples fabricated in accordance with the methods of this invention have the common feature of at least one hydrophilic fluid delivery passage. In one embodiment, the fluid delivery passage is a microtube. In another embodiment, the fluid delivery passage is a microchannel. In yet another embodiment, the fluid delivery passage comprises a porous reticulated foam with interconnected pores. In each of these embodiments, the fluid delivery passage has at least one dimension in the range of 1-2000 microns.
Abstract:
Microdevices based on surface tension and wettability are useful as sensors, detectors, actuators, pumps, among other applications. As sensors and detectors they can respond to numerous stimuli such as pressure, temperature, gravity, rotation, acceleration, oscillation, chemical environments, magnetic fields, electric fields, radiation, and particle beams with a great choice of output options. Because of their design, they can be used in a broad range of temperatures and environments. Additionally, unlike other microsensors and detectors, these devices can be exposed to forces and pressures orders of magnitudes greater than their design limit and still return to their original accuracy and precision. These microdevices are also useful as actuators, pumps, valves and shutters. It is possible by joining these devices together to form complex devices that are able to control macroscopic flows for example. They are also able to perform complex electrical switching operations.