Slow‐Wave Structures Utilizing Superconducting Thin‐Film Transmission Lines

Slow‐wave propagation of electromagnetic waves in transmission lines formed of thin‐film superconductors has been studied theoretically and experimentally. Previous theoretical analyses have been extended to include nonlocal theories. Strong dependence of phase velocity is found on film thickness and interfilm spacing when these become less than a few penetration depths. Velocity is also modified by coherence length, mean free path, nature of reflection of electrons at the film surfaces, and by temperature and magnetic field. Experimental measurements were made to verify the dependence on thickness, spacing, and temperature by means of a resonance technique. Agreement with theory was excellent in the case of temperature. Data taken for varying thickness and spacing verified the general trend of theoretical predictions. They indicate a nonlocal behavior with some specular reflection, but scatter of the data taken for different films prevents precise comparison of theory and experiment. Estimates of bulk penetration depths were made for indium, λ_In = 648±130 Å. For tantalum a rough estimate could be made of λTa = 580 Å. Data were consistent with the estimate of coherence length for indium of ξ_0 ≈ 3000 Å. Velocity was found to be independent of frequency in the range 50–500 MHz, while losses increased as the square. Pulse measurements indicated that delays of several microseconds and storage of several thousand pulses on a single line are feasible

Causes of U.S. Bank Distress During the Depression

This paper provides the first comprehensive econometric analysis of the causes of bank distress during the Depression. We assemble bank-level data for virtually all Fed member banks, and combine those data with county-level, state-level, and national-level economic characteristics to capture cross-sectional and inter-temporal variation in the determinants of bank failure. We construct a model of bank survival duration using these fundamental determinants of bank failure as predictors, and investigate the adequacy of fundamentals for explaining bank failures during alleged episodes of nationwide or regional banking panics. We find that fundamentals explain most of the incidence of bank failure, and argue that contagion' or liquidity crises' were a relatively unimportant influence on bank failure risk prior to 1933. We construct upper-bound measures of the importance of contagion or liquidity crises. At the national level, we find that the first two banking crises identified by Friedman and Schwartz in 1930 and 1931 are not associated with positive unexplained residual failure risk, or with changes in the importance of liquidity measures for forecasting bank failures. The third banking crisis they identify is a more ambiguous case, but even if one views it as a bona fide national liquidity crisis, the size of the contagion effect could not have been very large. The last banking crisis they identify at the beginning of 1933 is associated with important, unexplained increases in bank failure risk. We also investigate the potential role of regional or local contagion and illiquidity crises for promoting bank failure and find some evidence in support of such effects, but these are of small importance in the aggregate. We also investigate the causes of bank distress measured as deposit contraction, using county-level measures of deposits of all commercial banks, and reach similar conclusions about the importance of fundamentals in determining deposit contraction.

Contagion and Bank Failures During the Great Depression: The June 1932 Chicago Banking Panic

Studies of pre-Depression banking argue that banking panics resulted from depositor confusion about the incidence of shocks, and that interbank cooperation avoided unwarranted failures. This paper uses individual bank data to address the question of whether solvent Chicago banks failed during the panic asthe result of confusion by depositors. Chicago banks are divided" into three groups: panic failures, failures outside the panic window, and survivors. The characteristics of these three groups are compared to determine whether the banks that failed during the panic were similar ex ante" to those that survived the panic or whether they shared characteristics with other banks that failed. Each category of comparison -- the market-to-book value of equity, the estimated probability or failure or duration of survival the composition of debt, the rates of withdrawal of debt during 1931, and the interest rates paid on debt -- leads to the same conclusion: banks that failed during the panic were similar to others that failed and different from survivors. The special attributes of failing banks were distinguishable at least six months before the panic and were reflected in stock prices, failure probabilities, debt composition, and interest rates at least that far in advance. We conclude that failures during the panic reflected relative weakness in the face of common asset value shock rather than contagion. Other evidence points to cooperation among solvent Chicago banks a key factor in avoiding unwarranted bank failures during the panic.

Resolving the puzzle of the underissuance of national bank notes

The puzzle of underissuance of national bank notes disappears when one disaggregates data, takes account of regulatory limits, and considers differences in opportunity costs. Banks with poor lending opportunities maximized their issuance. Other banks chose to limit issuance. Redemption costs do not explain cross-sectional variation in issuance, and the observed relationship between note issuance and excess reserves is inconsistent with the redemption risk hypothesis of underissuance. National banks did not enter primarily to issue national bank notes, and a “pure arbitrage” strategy of chartering a national bank only to issue national bank notes would not have been profitable. Indeed, new entrants issued less while banks exiting were often maximum issuers. Economies of scope between note issuing and deposit banking included shared overhead costs and the ability to reduce costs of mandatory minimum reserve and capital requirements.Bank notes ; National banks (United States)

Credit card securitization and regulatory arbitrage

This paper explores the motivations and desirability of off-balance-sheet financing of credit card receivables by banks. We explore three related issues: the degree to which securitizations result in the transfer of risk out of the originating bank, the extent to which securitization permits banks to economize on capital by avoiding regulatory minimum capital requirements, and whether banks' avoidance of minimum capital regulation through securitization with implicit recourse has been undesirable from a regulatory standpoint. We show that this intermediation structure could be motivated either by desirable efficient contracting in the presence of asymmetric information or by undesirable safety net abuse. We find that securitization results in some transfer of risk out of the originating bank but that risk remains in the securitizing bank as a result of implicit recourse. Clearly, then, securitization with implicit recourse provides an important means of avoiding minimum capital requirements. We also find, however, that securitizing banks set their capital relative to managed assets according to market perceptions of their risk and seem not to be motivated by maximizing implicit subsidies relating to the government safety net when managing their risk. Thus, the evidence is more consistent with the efficient contracting view of securitization with implicit recourse than with the safety net abuse view. Concerns expressed by policymakers about this form of capital requirement avoidance appear to be overstated. ; Also issued as Payment Cards Center Discussion Paper No. 03-05Credit cards

Resolving the Puzzle of the Underissuance of National Bank Notes

The puzzle of underissuance of national bank notes disappears when one disaggregates data, takes account of regulatory limits, and considers differences in opportunity costs. Banks with poor lending opportunities maximized their issuance. Other banks chose to limit issuance. Redemption costs do not explain cross-sectional variation in issuance and the observed relationship between note issuance and excess reserves is inconsistent with the redemption risk hypothesis of underissuance. National banks did not enter primarily to issue national bank notes, and a "pure arbitrage" strategy of chartering a national bank only to issue national bank notes would not have been profitable. Indeed, new entrants issued less while banks exiting were often maximum issuers. Economies of scope between note issuing and deposit banking included shared overhead costs and the ability to reduce costs of mandatory minimum reserve and capital requirements.

Extended frequency turbofan model

The fan model was developed using two dimensional modeling techniques to add dynamic radial coupling between the core stream and the bypass stream of the fan. When incorporated into a complete TF-30 engine simulation, the fan model greatly improved compression system frequency response to planar inlet pressure disturbances up to 100 Hz. The improved simulation also matched engine stability limits at 15 Hz, whereas the one dimensional fan model required twice the inlet pressure amplitude to stall the simulation. With verification of the two dimensional fan model, this program formulated a high frequency F-100(3) engine simulation using row by row compression system characteristics. In addition to the F-100(3) remote splitter fan, the program modified the model fan characteristics to simulate a proximate splitter version of the F-100(3) engine

Did doubling reserve requirements cause the recession of 1937-1938? a microeconomic approach

In 1936-37, the Federal Reserve doubled the reserve requirements imposed on member banks. Ever since, the question of whether the doubling of reserve requirements increased reserve demand and produced a contraction of money and credit, and thereby helped to cause the recession of 1937-1938, has been a matter of controversy. Using microeconomic data to gauge the fundamental reserve demands of Fed member banks, we find that despite being doubled, reserve requirements were not binding on bank reserve demand in 1936 and 1937, and therefore could not have produced a significant contraction in the money multiplier. To the extent that increases in reserve demand occurred from 1935 to 1937, they reflected fundamental changes in the determinants of reserve demand and not changes in reserve requirements.Money supply ; Bank reserves ; Recessions

A New Genus of Exodont lchneutinae (Hymenoptera: Braconidae)

Two new species of Muesebeckiini, Ichneutinae, are described as a new genus characterized by exodont mandibles and by alternate pairs of abdominal spiracles missing. Most specimens have been found in northern Florida and a few in eastern Texas

A New Genus of Exodont lchneutinae (Hymenoptera: Braconidae)

Two new species of Muesebeckiini, Ichneutinae, are described as a new genus characterized by exodont mandibles and by alternate pairs of abdominal spiracles missing. Most specimens have been found in northern Florida and a few in eastern Texas