Abstract:
Resistance heating, preferably with applied pressure, is used to consolidate incremental volumes of material to produce a desired object in accordance with a description thereof. The joining of the material increments may occur in the solid state, liquid state, or ‘mushy’ state in conjunction an atomically clean faying surface between the increments without melting the material in bulk. Residual stresses are minimized, particularly in metal objects, by imposing a compressive residual stress on the surface of each deposited layer or increment, which offsets all or a portion of the tensile stress created as the next layer deposited above it cools. In terms of apparatus, a moving cathode is used to ensure uniform electrical current flow in an object with constantly changing geometry. The contact resistance of the interface between the workpieces is preferably continuously measured, and the sensor data is used to update a look-up table, or as input to an adaptive closed loop control system to ensure consistent welding conditions as object geometry changes continually. Also disclosed are embodiments associated with the fabrication of functionally gradient materials.
Abstract:
An electro-hydrodynamic system that extracts energy from a gas stream, which includes an injector that injects a first species of particles having the same polarity into the gas stream, wherein particle movement with the gas stream is opposed by a first electric field; an electric field generator that generates a second electric field opposing the first, such that the net electric field at a predetermined distance downstream from the injector is approximately zero; an upstream collector that collects a second species of particles having a polarity opposite the first particle species; a downstream collector that collects the charged particle; and a load coupled between the downstream collector and the upstream collector, wherein the load converts the kinetic energy of the gas stream into electric power.
Abstract:
Anti-tamper enclosures for electronic devices incorporate a variety of passive and active anti-tampering techniques in a novel way, using highly specialized manufacturing techniques that uniquely and innovatively allow such enclosures to be fabricated. Different embodiments include, alone or in combination, enclosures that prevent x-ray and field-ion-beam characterization of the device; detect attempts to mechanically open the enclosure via prying, cutting, machining, etc.; support wireless communication out of the enclosure so that attempts to tamper with the device can be reported to a user; allow insertion of “decoy” devices; and provide a method of destroying the device as a response to a tampering attempt.
Abstract:
Methods of fabricating a metal-matrix composite materials comprise the steps of providing a plurality of fibers, providing a plurality of metal wires, positioning the wires and fibers in alternating fashion on a substrate, covering the wires and fibers with a layer of metal to create a multi-layer composite, and ultrasonically consolidating the composite. Titanium, aluminum and alloys and other metals are applicable to the process. The fibers may be boron, silicon carbide, glass, alumina and other common reinforcements or, alternatively, optical fibers, shape-memory fibers, piezo-ceramic fibers may be used. The fibers or the wires may be of uniform or varying composition, and may b are applied to a working surface separately or simultaneously, in which case they may be collimated and delivered to a working surface in aligned fashion.
Abstract:
A system for energy and particle extraction from an exhaust stream containing entrained particles, the system including an ionizer, a downstream collector, and an electrical couple. The ionizer is configured to charge the particles within the exhaust stream to a first charge polarity. The downstream collector is disposed downstream from the ionizer within the exhaust stream, and is configured to collect the charged particles. The electrical couple is configured to electrically couple a load between the ionizer and the downstream collector, wherein the load converts energy of the exhaust stream into electric power.
Abstract:
A system for electro-hydrodynamically extracting energy from wind includes an upstream collector that is biased at an electric potential and induces an electric field. An injector introduces a particle into the electric field. The wind drag on the particle is at least partially opposed by a force of the electric field on the particle. A sensor monitors an ambient atmospheric condition, and a controller changes a parameter of the injector in response to a change in the atmospheric condition.
Abstract:
Provided are electro-hydrodynamic (EHD) system for extracting energy from wind. Also provided are injectors for producing particles in an EHD system. Additionally, methods for producing particles in an EHD system is also provided. Further provided are displays comprising an EHD wind energy system. Also, an electro-hydrodynamic wind energy system integrated with a display is provided. A method of generating electricity is also provided. Additionally, a method of displaying a message is provided.
Abstract:
A continuous, single-step, low-temperature process combines metal coating with the splicing of fibers, producing a single, continuous low-cost process for embedding fibers in metal, and/or the splicing of fibers with a joint featuring uniform composition and high strength requiring no additional adhesives. The method can be used to create terminations for cables, or it can be used as a method of splicing or joining optical fibers by positioning the ends of the two fibers under the foils, so that they abut prior to creating the bond. The consolidation material may be provided in sheets, with or without fiber-locating grooves or, alternatively, droplets may be used. In the preferred embodiment, ultrasonic vibrations are used as the source of consolidation energy. A range of metals are suited to the process, including aluminum, copper, titanium, nickel, iron and their alloys as well a numerous other metals of more limited structural utility.
Abstract:
A system and a method of fabricating a three-dimensional object on a substrate includes adding material layers incrementally and consolidating the layers by using ultrasonic vibrations and pressure. The layers are placed in position to shape the object by a material feeding unit, and they come in various forms, including flat sheets, segments of tape, strands of filament or single dots of material. The material may be plastic or metallic, and composition may vary discontinuously or gradually from one layer to the next, creating a region of functionally gradient material. The invention permits the construction and repair of dense objects, including fiber-reinforced composites and aerospace structures. Excess material may be removed one or more layers are bonded, including following end of the process after the final object is fabricated. The layers are fed sequentially and additively according to a layer-by-layer computer-model description of the object, which is generated by a computer-aided design/manufacturing (CAD/CAM) system. Ultrasonic welding equipment applicable to the invention preferably includes an ultrasonic generator, a transducer, a booster and a head unit or sonotrode.
Abstract:
Machine tools combine material addition via ultrasonic object consolidation and subtractive techniques for imparting high-dimensional accuracy to a finished object. A material supply and feeder, ultrasonic horn, and feedstock cutting device are integrated with a material removal subsystem preferably including a cutting tool and an excess material removal system. Any metal, plastic or composite material suitable for ultrasonic joining may be employed as a feedstock, and these material may assume the form of tapes, sheets, wires, filaments, dots or droplets, with the feeding and material cutting components being designed for the specific feedstock employed. The cutting tool for excess material removal, may be a knife, drill/mill, grinding tool, or other tool capable of accurately cutting the external contour of a cross section of the part being built, and for removing excess feedstock remaining following the application process. The material removal could consist of a vacuum or blower system, chip auger, or other suitable apparatus. A machine disclosed as part of the preferred embodiment is able to deposit material in one step, and optionally and selectively remove it in another. Through the expeditious combination of deposition and removal, the fabrication of objects of arbitrary shape may be realized.