2,072 research outputs found
Electroplating on titanium alloy
Activation process forms adherent electrodeposits of copper, nickel, and chromium on titanium alloy. Good adhesion of electroplated deposits is obtained by using acetic-hydrofluoric acid anodic activation process
Solar energy absorption characteristics and the effects of heat on the optical properties of several coatings
The solar energy absorption characteristics of several high temperature coatings were determined and effects of heat on these coatings were evaluated. Included in the investigation were an electroplated alloy of black chrome and vanadium, electroplated black chrome, and chemically colored 316 stainless steel. Each of the coatings possessed good selective solar energy absorption properties at laboratory ambient temperature. Measured at a temperature of 700 K (800 F), the emittances of black chrome, black chrome vanadium, and colored stainless steel were 0.11, 0.61, and 0.15, respectively. Black chrome and black chrome vanadium did not degrade optically in the presence of high heat (811 K (1000 F)). Chemically colored stainless steel showed slight optical degradation when exposed to moderately high heat (616 K (650 F)0, but showed more severe degradation at exposure temperatures beyond this level. Each of the coatings showed good corrosion resistance to a salt spray environment
Investigation of the Technical Micronics Control /TMC/ Process for Electropolishing Various Metals
Technical micronics control process for electropolishing metals and alloy
Solar absorption characteristics of several coatings and surface finishes
Solar absorption characteristics are established for several films potentially favorable for use as receiving surfaces in solar energy collectors. Included in the investigation were chemically produced black films, black electrodeposits, and anodized coatings. It was found that black nickel exhibited the best combination of selective optical properties of any of the coatings studied. A serious drawback to black nickel was its high susceptibility to degradation in the presence of high moisture environments. Electroplated black chrome generally exhibited high solar absorptivities, but the emissivity varied considerably and was also relatively high under some conditions. The black chrome had the greatest moisture resistance of any of the coatings tested. Black oxide coatings on copper and steel substrates showed the best combination of selective optical properties of any of the chemical conversion films studied
Environmental durability of electroplated black chromium
A study was undertaken to determine the durability of nickel-black chromium plated aluminum in an outdoor rural industrial, and seacoast environment. Test panels were exposed to these environments for 60, 36, and 13 months, respectively. The results of this study showed that no significant optical degradation occurred from exposure to either of these environments, although a considerable amount of corrosion occurred on the panels exposed to the seacoast environment. The rural and industrial atmosphere produced only a slight amount of corrosion on test panels
Financial Expertise as an Arms Race
We propose a model in which firms involved in trading securities overinvest in financial expertise. Intermediaries or traders in the model meet and bargain over a financial asset. As in the bargaining model in Dang (2008), counterparties endogenously decide whether to acquire information, and improve their bargaining positions, even though the information creates adverse selection. We add to this setting the concept of "financial expertise" as resources invested to lower the cost of later acquiring information about the value of the asset being traded. These investments are made before the parties know about their role in the bargaining game, as proposer or responder, buyer or seller. A prisoner's dilemma arises because investments to lower information acquisition costs improve bargaining outcomes given the other party's information costs, even though the information has no social benefit. These investments lead to breakdowns in trade, or liquidity crises, in response to random but infrequent increases in asset volatilityFinancial services;over-the-counter markets;financial crisis
A theoretical and flight test study of pressure fluctuations under a turbulent boundary layer. Part 2: Flight test study
The study of pressure fluctuations under a turbulent boundary layer was undertaken with the objective of extending previous work to lower frequencies. Wind tunnel and flight test measurements are invalid at low frequencies because of extraneous acoustic noises and free stream turbulence. A glider was instrumented and used as a test bed to carry microphones into a smooth flow free of acoustic noise. Hodgson had previously measured the spectrum of boundary layer noise on a glider wing. These tests showed a drop off at low frequencies that could not be reproduced in any other facility. The measurements were made on the forward fuselage of a glider where the boundary layer could develop naturally and have some length in a zero pressure gradient before the measurements were made. Two different sets of measurements were made
In Trepidis Rebus: The Constitutional Basis of the Executive War Power
Traditional approaches to questions of executive war power emphasize presidential-congressional relations, and focus on the meaning and implications of specific constitutional clauses. This dissertation offers an alternative approach by examining executive war power through the higher, more normative purposes to which the Constitution aims. It views executive war power from the perspective of Constitution's basic but essential goal of self-preservation, and argues that the Presidency has a unique duty to preserve, protect, and defend the Constitution. Presidential power, therefore, should be viewed in light of its duties to preserving the constitutional order. Presidential power, however, should not be viewed as "anything goes" for, true to republican principles, the people ultimately are sovereign and have multiple constitutional means by which to hold their leaders accountable. The dissertation focuses its analysis on the Constitution's text, examining Publius and other writings of the Founding era, to help uncover the explicit purpose and implicit principles for understanding the Constitution. Understanding "to what end" the Constitution aims provides the lens through which we should view the actions of its institutions and officers. The dissertation then offers an interpretative analysis of President Washington's words and deeds during the Whiskey Rebellion, demonstrating that his construction of the executive war power offers an important contribution to U.S. constitutionalism. It also focuses on Lincoln's construction of the executive war power during the Civil War, arguing that although Lincoln exercised extraordinary power in meeting the necessity of the situation, he did so while remaining true to both the spirit and the letter of the Constitution. This counters conventional opinions that Lincoln's conduct was un- or extraconstitutional, or that he had to act outside of the Constitution in order to save it. The dissertation suggests that the constitutionalism and statesmanship of Washington and Lincoln offer much perspective for understanding issues surrounding the executive war power today
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