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Brazing

Proposed for publication in Encyclopedia of Material: Science & Technology.

Cadden, Charles H.

The use of a lower-melting-point molten metal to join metallic components is perhaps the earliest example of processing which employs metallurgical bonding principles, having roots as far back as 4200 BC (Peaslee 2003). More than 6000 years later, brazing occupies a prominent position in our suite of joining processes where it offers cost and/or performance advantages in the fabrication of many structures. More precisely, brazing can be described as the use of a molten filler metal to wet the closely fitting faying surfaces of a joint, leading to formation of metallurgical bonds between the filler metal and substrates. Historically, brazing processes employ filler metals whose solidus temperature exceeds 723 K, as opposed to soldering processes which use lower-melting-point temperature filler materials. In the past several decades, technological advances have facilitated a broadening of applications for brazing while simultaneously contradicting some of the traditional perceptions of the process. However, many of those tenets remain appropriate for the majority of brazing processes and products. Accordingly, this article provides a brief description of traditional brazing and some important factors to be considered when designing and producing brazed structures. An additional section describes the technical advances in the field.

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Effect of critical dimension variation on SAW correlator energy

Proposed for publication in IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control.

Skinner, J.L.

The effect of critical dimension (CD) variation and metallization ratio on the efficiency of energy conversion of a surface acoustic wave (SAW) correlator is examined. We find that a 10% variation in the width of finger electrodes predicts only a 1% decrease in the efficiency of energy conversion. Furthermore, our model predicts that a metallization ratio of 0.74 represents an optimum value for energy extraction from the SAW by the interdigitated transducer (IDT).

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The US/Global Achilles heel : economic terrorism

Backus, George A.

While loss of life is the operating concern of Department of Homeland Security (DHS), the security of the economy ultimately decides the success of the war on terrorism. This project focuses on mitigation, containment, response, and impact of terrorist events on the economy. Conventional economic methods are inadequate, but agent-based methods (Discrete Simulation) appears to uniquely capture the dynamics and emergent (human) behaviors.

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Early experience with red storm

Kelly, Suzanne M.; Ballance, Robert A.

Red Storm is a massively parallel processor. The Red Storm design goals are: (1) Balanced system performance - CPU, memory, interconnect, and I/O; (2) Usability - functionality of hardware and software meets needs of users for Massively Parallel Computing; (3)S calability - system hardware and software scale, single cabinet system to {approx} 30,000 processor system; (4) reliability - machines tays up long enough between interrupts to make real progress on completing application run (at least 50 hours MTBI), requires full system RAS capability; (5) Upgradability - system can be upgraded with a processor swap and additional cabinets to 100T or greater; (6) red/black switching - capability to switch major portions of the machine between classified and unclassified computing environments; (7) space, power, cooling - high density, low power system; and (8) price/performance - excellent performance per dollar, use high volume commodity parts where feasible.

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On the need and use of models to explore the role of economic confidence:a survey

Sprigg, James A.

Empirical studies suggest that consumption is more sensitive to current income than suggested under the permanent income hypothesis, which raises questions regarding expectations for future income, risk aversion, and the role of economic confidence measures. This report surveys a body of fundamental economic literature as well as burgeoning computational modeling methods to support efforts to better anticipate cascading economic responses to terrorist threats and attacks. This is a three part survey to support the incorporation of models of economic confidence into agent-based microeconomic simulations. We first review broad underlying economic principles related to this topic. We then review the economic principle of confidence and related empirical studies. Finally, we provide a brief survey of efforts and publications related to agent-based economic simulation.

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Results 86726–86750 of 99,299
Results 86726–86750 of 99,299