9,660 research outputs found
Global imbalances: the international monetary system and financial stability.
Understanding the link between global macroeconomic imbalances and financial stability is critical not only for understanding the recent financial crisis, but also for what could happen next. The imbalances and financial vulnerabilities that plagued the global economy before the crisis have begun to re-emerge. In a context of deficient global demand and exceptionally low interest rates in many countries, one likely result is excessively risky behaviour in the financial sector. A failure to resolve global disequilibria will ultimately undermine the global recovery and financial stability. Several lines of defence against this outcome are needed, including greater responsibility on the part of households, firms and governments to manage their debts, and enhanced financial sector supervision.
Liquid-vapor interface locations in a spheroidal container under low gravity
As a part of the general study of liquid behavior in low gravity environments, an experimental investigation was conducted to determine if there are equilibrium liquid-vapor interface configurations that can exist at more than one location in oblate spheroidal containers under reduced gravity conditions. Static contact angles of the test liquids on the spheroid surface were restricted to near 0 deg. The experiments were conducted in a low gravity environment. An oblate spheroidal tank was tested with an eccentricity of 0.68 and a semimajor axis of 2.0 cm. Both quantitative and qualitative data were obtained on the liquid-vapor interface configuration and position inside the container. The results of these data, and their impat on previous work in this area, are discussed. Of particular interest are those equilibrium interface configurations that can exist at multiple locations in the container
Evaluation of the communications impact of a low power arcjet thruster
The interaction of a 1 kW arcjet thruster plume with a communications signal is evaluated. A two-parameter, source flow equation has been used to represent the far flow field distribution of the arcjet plume in a realistic spacecraft configuration. Modelling the plume as a plasma slab, the interaction of the plume with a 4 GHz communications signal is then evaluated in terms of signal attenuation and phase shift between transmitting and receiving antennas. Except for propagation paths which pass very near the arcjet source, the impacts to transmission appear to be negligible. The dominant signal loss mechanism is refraction of the beam rather than absorption losses due to collisions. However, significant reflection of the signal at the sharp vacuum-plasma boundary may also occur for propagation paths which pass near the source
Institutional Change and Firm Adaptation
We develop a typology of organizational forms found in Southeast Asia that contains four major archetypes, Colonial Business Groups, Family Business Groups, Government Linked Enterprises, and New Managers. We explain how the institutional environment prevailing at their founding profoundly influence the strategies and capabilities of each form. Consequently, strategic repertoires and competencies that are imperfectly aligned with environmental conditions largely delimit the capacity for organizational adaptation in the face of environmental change. We discuss the consequences of such a pattern of path dependence for each organizational form as well as the social and economic systems in which they are embedded.family business groups;Southeast Asia;colonial business groups;institutional change;organizational adaptation
The effects of arcjet operating condition and constrictor geometry on the plasma plume
Measurements of plasma number density and electron temperature were obtained in the plumes of lab arcjet thrusters using electrostatic probes of both spherical and cylindrical geometry. The two arcjet thrusters used had different constrictor and/or nozzle geometries and operated on mixtures of nitrogen, hydrogen, and ammonia to simulate the decomposition products of hydrazine and ammonia. An increase in the measured electron density was observed for both geometries with increasing arc power at a constant mass flow rate and with increasing mass flow rate at a constant arc current. For a given operating condition, the electron number density decreased exponentially off centerline and followed an inverse distance squared relationship along the thrust axis. Typical measured electron temperatures ranged from 0.1 to 0.2 eV
Investigation of a liquid-fed water resistojet plume
Measurements of mass flux and flow angle were taken throughout the forward flow region of the exhaust of a liquid-fed water resistojet using a quartz crystal microbalance (QCM). The resistojet operated at a mass flow rate of 0.1 g/s with a power input of 330 Watts. Measured values were compared to theoretical predictions obtained by employing a source flow approximation. Excellent agreement between predicted and measured mass flux values was attained; however, this agreement was highly dependent on knowledge of nozzle flow conditions. Measurements of the temperature at which the exhaust condensed on the QCM were obtained as a function of incident mass flux
Experimental evaluation of resistojet thruster plume shields
The exhaust of an engineering model resistojet has been investigated using rotary pitot probes and a rotary quartz crystal microbalance. The resistojet operated on CO2 propellant at a mass flow rate of 0.29 g/sec in both heated and unheated flows. Measurements of local flow angles in the near field of a conical plume shield indicated that the shield was not wholly effective in confining the flow to the region upstream of its exit plane. However, the absolute levels of the measured mass flux into the backflow region were very low, on the order of 7 x 10 to the -7 power g/sqcm/sec or less. The use of a circualr disk at the exit plane of the existing conical shield showed some benefit in decreasing the amount of backflow by a factor of two. Lastly, a detached shield placed upstream of the resistojet exit plane demonstrated a small degree of local shielding for the region directly behind it
NASA Lewis Research Center low-gravity fluid management technology program
A history of the Lewis Research Center in space fluid management technology program is presented. Current programs which include numerical modeling of fluid systems, heat exchanger/radiator concept studies, and the design of the Cryogenic Fluid Management Facility are discussed. Recent analytical and experimental activities performed to support the Shuttle/Centaur development activity are highlighted
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