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Posted in: Blog

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How a Supercomputing Innovation Accelerated a Business

Larry Lukis Founder and CTO Proto Labs, Inc. Maple Plain, MN Proto Labs is a quick-response custom manufacturer that provides design engineers with prototypes of plastic parts faster than anyone in the world. Our Protomold division produces prototypes (and short run production parts) by injection molding, and our First Cut Prototype division produces prototypes by CNC machining plastic stock.

Posted in: Articles

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Fault-Tolerant Coding for State Machines

State machines can be rendered immune to single-event upsets. Two reliable fault-tolerant coding schemes have been proposed for state machines that are used in field-programmable gate arrays and application-specific integrated circuits to implement sequential logic functions. The schemes apply to strings of bits in state registers, which are typically implemented in practice as assemblies of flip-flop circuits. If a single-event upset (SEU, a radiation- induced change in the bit in one flip-flop) occurs in a state register, the state machine that contains the register could go into an erroneous state or could “hang,” by which is meant that the machine could remain in undefined states indefinitely. The proposed fault-tolerant coding schemes are intended to prevent the state machine from going into an erroneous or hang state when an SEU occurs.

Posted in: Briefs, TSP

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Vacuum Packaging of MEMS With Multiple Internal Seal Rings

Each internal seal ring would be part of an electrical feed-through. A proposed method of design and fabrication of vacuum-packaged microelectromechanical systems (MEMS) and of individual microelectromechanical devices involves the use of multiple internal seal rings (MISRs) in conjunction with vias (through holes plated with metal for electrical contacts). The proposed method is compatible with mass production in a wafer-level fabrication process, in which the dozens of MEMS or individual microelectromechanical devices on a typical wafer are simultaneously vacuum packaged by bonding a capping wafer before the devices are singulated (cut apart by use of a dicing saw). In addition to being compatible with mass production, the proposed method would eliminate the need for some complex and expensive production steps and would yield more reliable vacuum seals.

Posted in: Briefs, TSP

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Nanophase Nickel-Zirconium Alloys for Fuel Cells

Corrosion resistance can be achieved at lower cost. Nanophase nickel- zirconium alloys have been investigated for use as electrically conductive coatings and catalyst supports in fuel cells. Heretofore, noble metals have been used because they resist corrosion in the harsh, acidic fuel-cell interior environments. However, the high cost of noble metals has prompted a search for less-costly substitutes.

Posted in: Materials, Briefs, TSP

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Atomized BaF2-CaF2 for Better-Flowing Plasma-Spray Feedstock

Water atomization is better suited to high-volume production of metal fluoride than conventional methods. Atomization of a molten mixture of BaF2 and CaF2 has been found to be superior to crushing of bulk solid BaF2- CaF2 as a means of producing eutectic BaF2-CaF2 powder for use as an ingredient of the powder feedstock of a hightemperature solid lubricant material known as PS304. Developed to reduce friction and wear in turbomachines that incorporate foil air bearings, PS304 is applied to metal substrates by plasma spraying. The constituents of PS304 are:

Posted in: Materials, Briefs, TSP

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Low-Pt-Content Anode Catalyst for Direct Methanol Fuel Cells

The costs of fuel-cell anodes could be reduced substantially. Combinatorial experiments have led to the discovery that a nanophase alloy of Pt, Ru, Ni, and Zr is effective as an anode catalyst material for direct methanol fuel cells. This discovery has practical significance in that the electronic current densities achievable by use of this alloy are comparable or larger than those obtained by use of prior Pt/Ru catalyst alloys containing greater amounts of Pt. Heretofore, the high cost of Pt has impeded the commercialization of direct methanol fuel cells. By making it possible to obtain a given level of performance at reduced Pt content (and, hence, lower cost), the discovery may lead to reduction of the economic impediment to commercialization.

Posted in: Briefs, TSP

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