550 research outputs found
Sovereign debt restructuring : the judge, the vultures and creditor rights
What role did the US courts play in the Argentine debt swap of 2005? What implications does this have for the future of creditor rights in sovereign bond markets?
The judge in the Argentine case has, it appears, deftly exploited creditor heterogeneity â between holdouts seeking capital gains and institutional investors wanting a settlement â to promote a swap with a supermajority of creditors. Our analysis of Argentine debt litigation reveals a âjudge-mediatedâ sovereign debt restructuring, which resolves the key issues of Transition and Aggregation - two of the tasks envisaged for the IMFâs still-born Sovereign Debt Restructuring Mechanism.
For the future, we discuss how judge-mediated sovereign debt restructuring (together with creditor committees) could complement the alternative promoted by the US Treasury, namely collective action clauses in sovereign bond contracts
Characterization of Chromate Conversion Coating Formation and Breakdown Using Electrode Arrays
Chromate conversion coating (CCC) formation and breakdown was examined using 25 element Al wire electrode arrays. Arrays were interrogated using a multichannel analyzer capable of separately recording currents from each electrode. During CCC formation, electrodes exhibited a 30 s period of intense electrochemical activity characterized by large net currents. On any given element, net current polarity was found to be predominantly anodic, predominately cathodic, or mixed. After 30 s, net currents decayed to small values, which remained small out to 300 s of exposure. Raman spectroscopy showed that Cr^6+ concentrations in the coating continued to increase during this electrochemically quiescent period, suggesting continued CCC evolution. Conversion-coated arrays were subject to anodic potentiodynamic polarization in 0.5 M NaCl until all elements on the array exhibited coating breakdown and substrate pitting. Breakdown potentials were found to increase with coating time up to 120 s, indicating anodic inhibition in CCC corrosion protection. Breakdown was found to be more difficult on electrodes that were net cathodes during coating formation. Results also showed that the NaF and K_3Fe(CN)_6 in commercial CCC bath formulations strongly contributed to coating corrosion resistance. Without Fv, the Al surface passivated quickly during coating formation, and a nonprotective film formed. Without Fe(CN)_3^6-, CCCs exhibited lower breakdown potentials
Raman Spectroscopy Characterization of Aqueous Vanadate Species Interaction with Aluminum Alloy 2024-T3 Surfaces
Raman spectroscopy and electrochemical techniques were used to characterize the interactions of aqueous NaVO_3/NaCl and NH_4VO_3/oxalic acid with AA 2024-T3. The interaction of aqueous NaVO_3 with Cu^0 and Cu_2O was characterized. At potential values similar to the OCP of AA 2024-T3 in dilute NaCl, aqueous NaVO_3 formed a polyvanadate film on Cu_2O and formed little or no vanadate film on Cu^0. Treatment of AA 2024-T3 with basic, aqueous NaVO_3/NaCl resulted in a polyvanadate film on copper-rich intermetallic particles and the formation of monovanadates on the matrix. Treatment of AA 2024-T3 with acidic, aqueous NH_4VO_3/oxalic resulted in the formation of monovanadates on the matrix and provided no evidence of vanadate species on copper-rich particles. AA 2024-T3 samples pretreated with either aqueous vanadate salt solution displayed modest cathodic inhibition soon after treatment but inhibition degraded with aging. The formation of polymerized vanadates species on copper-rich particles supports the cathodic inhibition mechanism. The presence of vanadate species on copper-rich particles pretreated with aqueous NaVO_3/NaCl containing predominantly tetrahedral vanadates versus the lack of evidence for similar species on particles treated with aqueous NH_4VO_3/oxalic acid containing predominantly octahedral vanadates supports the importance of tetrahedrally coordinated vanadate species for corrosion inhibition
Low-cycle fatigue of Type 347 stainless steel and Hastelloy alloy X in hydrogen gas and in air at elevated temperatures
An investigation was conducted to assess the low-cycle fatigue resistance of two alloys, Type 347 stainless steel and Hastelloy Alloy X, that were under consideration for use in nuclear-powered rocket vehicles. Constant-amplitude, strain-controlled fatigue tests were conducted under compressive strain cycling at a constant strain rate of 0.001/sec and at total axial strain ranges of 1.5, 3.0, and 5.0 %, in both laboratory-air and low-pressure hydrogen-gas environments at temperatures from 538 to 871 C. Specimens were obtained from three heats of Type 347 stainless steel bar and two heats of Hastelloy Alloy X. The tensile properties of each heat were determined at 21, 538, 649, and 760 C. The continuous cycling fatigue resistance was determined for each heat at temperatures of 538, 760, and 871 C. The Type 347 stainless steel exhibited equal or superior fatigue resistance to the Hastelloy Alloy X at all conditions of this study
Electrochemical Evaluation of Constituent Intermetallics in Aluminum Alloy 2024-T3 Exposed to Aqueous Vanadate Inhibitors
Experiments were conducted to determine how inhibiting forms of vanadate interact with complex Al alloy microconstituent intermetallics to impart corrosion protection. Cathodic polarization experiments on Al 2024-T3 indicate a strong correlation between inhibition and the presence of tetrahedrally coordinated vanadate. Anodic and cathodic polarization curves were measured on bulk synthesized Al_2Cu, Al_2CuMg, Al_7Cu_2Fe, and Al_20Cu_2Mn_3 in alkaline 0.5 M NaCl solutions with and without 10 mM NaVO_3. Vanadate additions generally decreased E_corr, increased E_pit, and decreased the cathodic kinetics of all tested materials. Because of decreased cathodic kinetics, open-circuit potentials (OCPs) were shifted in the active direction in aerated solutions when vanadate was present. This shift pins the OCP just below the observed pitting potential for Al_2CuMg in vanadate solution, effectively preventing breakdown and subsequent support of rapid oxygen reduction by Cu-enriched clusters. E_corr, E_pit, E_rp, i_corr, i_pass, and i at â1.3 V_SCE data from polarization experiments were summarized in cumulative distribution plots, and averages are presented in tabulated format. Scanning electron microscopy images of Al 2024-T3 used for 4 h of OCP measurement show that vanadate greatly decreased circumferential trenching around intermetallic particles in both aerated and deaerated solutions. Potentiostatic hold experiments were used to show suppression of Al_2CuMg dissolution in vanadate solutions
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