Advanced supersonic technology fuel tank sealants

Status of the fuel tank simulation and YF-12A flight tests utilizing a fluorosilicone sealant is described. New elastomer sealant development is detailed, and comparisons of high and low temperature characteristics are made to baseline fluorosilicone sealants

Polyimide fiber-glass composite resists high temperatures

Composites synthesized from bismaleimide have superior strength and oxidation resistance at elevated temperatures when compared with similar composites prepared with epoxy or silicon polymers of similar cost. Polyimide synthesis technique and processing method yield essentially void-free fiber-glass reinforced composites

The NASTRAN Error Correction Information System (ECIS)

A data management procedure, called Error Correction Information System (ECIS), is described. The purpose of this system is to implement the rapid transmittal of error information between the NASTRAN Systems Management Office (NSMO) and the NASTRAN user community. The features of ECIS and its operational status are summarized. The mode of operation for ECIS is compared to the previous error correction procedures. It is shown how the user community can have access to error information much more rapidly when using ECIS. Flow charts and time tables characterize the convenience and time saving features of ECIS

Nonlinear bubbles in Chinese Stock Markets in the 1990s

A time series of the Shanghai stock index in China for the 1990s is studied for the possible existence of nonlinear speculative bubbles. Three alternative specifications of fundamentals are estimated using VAR models of domestic and international variables. These are subjected to regime switching tests and rescaled range analysis tests. Nulls of no persistence were mostly rejected, suggesting the strong possibility of bubbles. Nonlinearities beyond ARCH effects using the BDS test could not be rejected. The paper also discusses the special circumstances of the stock market in an emerging transition economy.

Fiber-modified polyurethane foam for ballistic protection

Closed-cell, semirigid, fiber-loaded, self-extinguishing polyurethane foam material fills voids around fuel cells in aircraft. Material prevents leakage of fuel and spreading of fire in case of ballistic incendiary impact. It also protects fuel cell in case of exterior fire

The Complexity Era in Economics

This article argues that the neoclassical era in economics has ended and is being replaced by a new era. What best characterizes the new era is its acceptance that the economy is complex, and thus that it might be called the complexity era. The complexity era has not arrived through a revolution. Instead, it has evolved out of the many strains of neoclassical work, along with work done by less orthodox mainstream and heterodox economists. It is only in its beginning stages. The article discusses the work that is forming the foundation of the complexity era, and how that work will likely change the way in which we understand economic phenomena and the economics profession.

Complex Dynamics of Macroeconomic Collapse and Its Aftermath in Transition Economies

The economic transition from planned command socialism to market capitalism has been unpredictable and complicated with a variety of divergent paths and outcomes emerging from the breakup and collapse of the former Soviet-led Council for Mutual Economic Assistance (CMEA) bloc. Although social, political, and cultural factors played important roles in the actual collapse, an underlying factor was increasing economic stagnation, especially in the USSR. This led to reform efforts that led to actual economic decline, the breakup of the bloc, and systemic collapse [Rosser and Rosser, 199Va]. The unexpected and dramatically sudden nature of this collapse led Sargent [1993] to doubt the rational expectations hypothesis. In this paper we seek to partially explicate the varieties of these episodes of discontinuity and turbulence by considering some forms of complex nonlinear dynamics as applied to the stages of the systemic transition process.Macroeconomics; Transitional Economies

Nine-point difference solutions for Poisson's equation

AbstractIt is shown that “stencils” exist for the sixth order solution of Poisson's equation by use of a nine-point difference approximation