Fuel stagnation temperature effects on mixing with supersonic combustion flows

An experimental study of the effect of fuel stagnation temperature on mixing in a supersonic hydrogen-air flame is described, The combustor consisted of a constant-area rectangular duct with a centrally located fuel-injection strut that spanned the width. A high-enthalpy stream of air was supplied by a free-piston shock tunnel, and heated hydrogen fuel, supplied by a gun-tunnel, was injected into the freestream as a coflowing planar jet. The freestream total enthalpies were 5.6, 6.5, and 9 MJ/kg, and fuel stagnation temperatures were 300, 450, and 700 K, Raising the fuel stagnation temperature increased the fuel velocity to be near that of the airstream and resulted in a decrease in the mixing rate, Even as the fuel and air velocities became equal, significant mixing still occurred because of a large difference in density, Increasing the freestream enthalpy reduced the difference between the initial air temperature and the adiabatic flame temperature, which in turn reduced the heat addition, and subsequently, the amount of pressure rise in the duct.

Can eccentric arterial plaques alone cause flow stagnation points and favour thrombus incorporation?

We have used an experimental model of aorta stenosis, with a Plexiglas plug, simulating a stable atheromatous plaque that promotes local turbulence and thrombosis. With animal survival of more than 24 h, we followed the partial fibrinolysis of the thrombus as well as its posterior organization and incorporation to the arterial wall as a neointima for up to 30 days. The mushroom plug form permitted the development of recirculation and stasis areas around it, favouring this evolution. Despite noted limitations, this study demonstrates that thrombus incorporation can contribute to plaque extension, as it can promote recirculation and stasis areas.

Essay on secular stagnation

In this paper we show that a closed economy, with a balanced budget and unable to increase public spending, can avoid or leave a persistent slump through adequate and timely combination of monetary and fiscal policy based on distortionary taxation. We use a three generations OLG New Keynesian model in which a permanent slump is possible without any self-correcting force to full-employment. Complementing recent work on Secular Stagnation using lump-sum taxation and government spending as fiscal instruments, our contribution is to use distortionary taxes over labor, consumption and capital, in a balanced budget environment with constant (or decreasing) government spending.

Portuguese stagnation in the 2001-2012 period

The 2001-2012 period has been one of very low growth for Portugal. This work project tries to find reasons for this slowdown. Growth in real GDP will be explained by several variables ranging from education, capital, government and world markets. Compensation of employees, capital per worker and the exports of competitors seem to explain a significant part of the slowdown. The ratio of non-tradables to tradables is also included but not significant, maybe due to a poor sample size. Stagnation then seems to be caused both by low growth in input accumulation and productivity as predicted by Amador and Coimbra in 2007.

A historical approach to the new secular stagnation hypothesis

In this paper, we analyze the behavior of real interest rates over the long-run using historical data for nine developed economies, to assess the extent to which the recent decline observed in most advanced countries is at odds with the past data, as suggested by the Secular Stagnation hypothesis. By using data from 1703 and performing stationarity and structural breaks tests, we find that the recent decline in interest rates is not explained by a structural break in the time series. Our results also show that considering long-run data leads to different conclusions than using short-run data.

The Stagnation Regime of the New Keynesian Model and Current US Policy

In Evans, Guse, and Honkapohja (2008) the intended steady state is locally but not globally stable under adaptive learning, and unstable deflationary paths can arise after large pessimistic shocks to expectations. In the current paper a modified model is presented that includes a locally stable stagnation regime as a possible outcome arising from large expectation shocks. Policy implications are examined. Sufficiently large temporary increases in government spending can dislodge the economy from the stagnation regime and restore the natural stabilizing dynamics. More specific policy proposals are presented and discussed.

Globalization, Divergence and Stagnation

In a world where poor countries provide weak protection for intellectual property rights, market integration shifts technical change in favor of rich nations. Through this channel, free trade may amplify international income differences. At the same time, integration with countries where intellectual property rights are weakly protected can slow down the world growth rate. A crucial implication of these results is that protection of intellectual property is most beneficial in open countries. This prediction, which is novel in the literature, finds support in the data on a panel of 53 countries observed in the years 1965-1990.

From semi-stagnation to growth in a sino-centric market

According to recent available information, the Brazilian economy may be entering a cycle of sustained growth. The dominant current interpretation points to the progresses made in terms of monetary stability, Balance of Payments and structural reforms. Indeed, without monetary stability and the commercial opening of the economy, investments would not be increasing and credit growth would not be helping the emergence of millions of new consumers. But these achievements should be taken as generally conditioning, rather than actually shaping the new picture. Some unexpected (not rarely positive) consequences of overcoming the long enduring semi-stagnation, the emergence of China as a major player, and its consequences on the necessary re-structuring of the Brazilian industry, seem to be decisive in the present day redefinition of the Brazilian GDP growth potential.

Economic stagnation in the United States: underlying causes and global consequences

This paper analyzes the causes of the slow recovery of the US economy since the financial crisis and Great Recession of 2008-9. Fallen house values and excessive household debts continue to depress consumer spending, while corporations are failing to invest in spite of record profits. The increasingly unequal distribution of income limits demand, while long-term structural transformations continue to erode employment creation. An expansionary monetary policy has been incapable of sparking a more robust recovery and fiscal policy has been shifted to an austerity stance. In this context, Brazil and other emerging market nations cannot count on the United States to continue to be the leading source of global demand as it was in previous decades.

Exploration du phénomène de la stagnation des performances chez le nageur de haut niveau

La stagnation est un phénomène fréquent dans le domaine de la natation, bien qu’inexpliqué et incompris, pour lequel peu de solutions sont proposées. Malgré quelques recherches sur ce phénomène, notamment au baseball, la littérature sur le sujet demeure incomplète et ne permet pas de bien cerner le problème de la stagnation. Ainsi, cette étude a pour but premier d’identifier et de comprendre les causes possibles de la stagnation, les changements émotionnels, physiques et sociaux engendrés par un tel phénomène et les stratégies utilisées par les athlètes pour gérer la stagnation. Le deuxième objectif de cette étude est de jeter un regard sur l’impact de l’optimisme sur la résolution de la stagnation. Pour ce faire, des entrevues semi-structurées ont été menées auprès de onze nageurs ayant compétitionné au niveau national canadien. Les nageurs étaient divisés en trois groupes: les nageurs ayant résolu leur stagnation et qui continuent de nager, les nageurs ayant cessé la compétition de natation suite à une stagnation non résolue et ceux qui nagent encore malgré une stagnation non résolue. Les candidats sélectionnés ont complété deux questionnaires sur l’optimisme, le LOT-R et l’ASQ. L’analyse des résultats, réalisée grâce à la théorisation ancrée, a permis de déterminer un ensemble d’émotions vécues par les athlètes et d’identifier des stratégies afin de résoudre la stagnation. Les résultats de cette étude indiquent qu’une balance entre l’optimisme et le pessimisme, une motivation intrinsèque ainsi qu’une auto-détermination chez l'athlète sont des éléments importants afin de surmonter une stagnation.

Brazil’s 35 years-old quasi-stagnation: facts and theory

Brazil is growing around 1% per capita a year from 1981; this means for a country that is supposed to catch up, quasi-stagnation. Four historical new facts explain why growth was so low after the Real Plan: the reduction of public savings, and three facts that reduce private investments: the end of the unlimited supply of labor, a very high interest rate, and the 1990 dismantling of the mechanism that neutralized the Dutch disease, which represented a major competitive disadvantage for the manufacturing industry. New-developmental theory offers an explanation and two solutions for the problem, but does not underestimate the political economy problems involved

Economic stagnation and alternative development strategies

The focus of my paper is the presentation of some thoughts on overcoming economic stagnation, with reference to the case of Mexico. In Section 2, I will describe the reasons why the policies of financial opening based on the Washington Consensus create endogenous tendencies toward economic stagnation and overvaluation of currencies. Section 3 offers a concise outline of a possible alternative development project for Mexico. Section 4 presents some proposals regarding monetary, foreign exchange, and fiscal policy oriented toward reviving economic growth. Finally, in Section 5, I present some conclusions.