Nutation Damper System

The Nutation Damper System is a three function mechanism designed for the Galileo Spacecraft, a spin stabilized deep-space probe to Jupiter. By damping the movement of a large deployable science boom acting as an outboard pendulum, the nutation damper rapidly stabilizes the spacecraft from dynamic irregularities. The system includes the boom deployment device and the ultra-low friction boom hinge. This paper describes the mechanism, the degree to which friction, stiction and lost motion have been eliminated, and the unique test methods that allow its performance to be measured

"Explaining the September 1992 ERM Crisis: The Maastricht Bargain and Domestic Politics in Germany, France and Great Britain"

At the time of the September 1992 crisis, the conventional wisdom held in the ERM was due to an unfortunate contuence of exceptional circumstances -- the shock of German reunification, a debt-driven recession in Britain, and the uncertainties caused by the Danish and French referenda on Maastricht. This paper points to systemic factors at both the EC and domestic levels in explaining the September crisis. At the Community level, it is argued that the ERM was the victim of an underlying structural flaw in the Maastricht 3-stage plan for EMU. Intergovemmental bargaining, reflecting the differing national preferences of Germany and France in particular, produced an untenable compromise with potentially chaotic consequences: the matching of demanding economic convergence criteria with a strict timetable for their fulfillment, upon commencement of Stage II of the EMU process set for January 1994. Far from being epiphenomenal, this bargain was only the latest manifestation of an ongoing debate between "economist" and monetarist" approaches to monetary integration, tracing back to the early 1970s. and I argue that the "framing effects" of the Stage II criteria fundamentally altered the nature of economic discourse at Stage I, beginning in 1990. Specific reference numbers for debt ratios and relative and interest rate targets emphasized economic divergence in countries with clearly overvalued currencies, and invited markets to test the strength of govemments' political commitments to their exchange rate pegs. The second component of my explanation of the September crisis lies at the domestic level. Even though strict convergence criteria and timetables provided a severe test of the credibility of members' European commitments, it was not a foregone conclusion that the Maastricht bargain would result in turbulence on the currency markets. A margin of maneuver was left to the member governments, through the demonstration of a willingness to take painful measures, such as fiscal and wage restraint or timely interest rate hikes, to defend the ERM commitment

Age structure and productivity growth

Among the most central questions at the intersection of demography and economics is the impact of large scale demographic processes on long-run economic performance. The classical version of this inquiry, occupying thinkers from Malthus towards those from the mid-to-late 20th century, had to do with whether rapid population growth threatened economic growth. This classical inquiry has been superseded by more sophisticated questioning in which the focus on growth rate of the aggregate population has been replaced by focus on the growth rates of age-specific population sub-groups. Disaggregating the effects of population growth by age-group is generally accepted to be a fundamental improvement over classical inquiry because people’s economic roles and contributions vary by age: the young are net consumers and beneficiaries of human capital investments, adults are net producers and savers, and the old are (at least in theory or to a greater degree than adults) net consumers. Thus the economic consequences of rapid growth in the population size of the young and the elderly could potentially have a depressing impact on growth, while rapid growth in the population size of adults could stimulate growth. The demographic transition brings with it a three stage process in which a baby boom cohort moves through the population’s age pyramid. The life cycle of this cohort creates a first stage in which there is rapid growth in youth population, then a second stage in which there is rapid growth in the adult population, and finally a third stage in which there is rapid growth in the elderly population. The first and third stages can be thought of as the challenging stages since economies must confront the challenge of providing for large dependent populations. However, the second stage can be thought of as a demographic gift or dividend stage since growth in the productive adult population can potentially boost economic growth. The traditional mechanisms for the demographic dividend include the impact of the boom cohort on labor supply, savings, and human capital. However, it seems to us that there has been no research on the potential impact of age structure on technological progress, which is unusual since all standard accounts of economic growth hold that in the long run, it is technological progress that is the sole source of improvement in living standards. Demographic impacts on technology could well dwarf the importance of everything else. There are two competing hypotheses regarding demographic processes and technological progress. One holds that a rapidly growing adult population stimulates technological progress, while the other holds that it retards it. Analyzing cross-country macro data from developing countries for the period 1970 to 2000, we find that entry of the baby boom cohort into the adult stage is correlated with higher labor productivity, even after controlling for capital accumulation and past productivity. Our evidence supports the view that the demographic dividend includes positive impacts on technological progress, which may in the long-run prove more consequential than any other demographic dividend consequences.age structure; productivity growth; demographic transition