5,918 research outputs found
Propellant combustion phenomena during rapid depressurization Final report
Idealized combustion model in which exothermic or endothermic reactions are permitted at or very near solid-gas interface
A theoretical and experimental study of propellant combustion phenomena during rapid depressurization Final report
Modified solid propellant combustion model for steady state analyses of burning rate and flame temperatur
An analytical study of solid propellant combustion during rapid depressurization Final report
Solid propellant combustion model modification to contain two heat release zones in gas phas
Meteorological application of Apollo photography Final report
Development of meteorological information and parameters based on cloud photographs taken during Apollo 9 fligh
Misallocation, Access to Finance, and Public Credit: Firm-Level Evidence
Using a database of 23,000 firms in 45 economies, we test the quantitative
importance of access to finance and access to public and private credit for the
determination of misallocation. We first derive measures of factor market and
size distortions, and then use these measures within a regression framework to
test the significance of self-declared access-to-finance obstacles as well as the
effect of access to a credit line issued by either a government-owned or private
bank. We find that access-to-finance obstacles and private credit increase the
dispersion of distortions. Public credit has a very small effect. For firms that do
not face financial obstacles, public credit increases the dispersion of distortions;
for firms that face financial obstacles, it slightly decreases dispersion. Public
credit does not appear to compensate for the distortions that exist in private
credit markets. Quantitatively, however, financial variables explain a very small
part of the dispersion of factor market and size distortions
On the role of monoterpene chemistry in the remote continental boundary layer
The formation of organic nitrates (RONO[subscript 2]) represents an important NO[subscript x] (NO[subscript x] = NO + NO[subscript 2]) sink in the remote and rural continental atmosphere, thus impacting ozone production and secondary organic aerosol (SOA) formation. In these remote and rural environments, the organic nitrates are primarily derived from biogenic volatile organic compounds (BVOCs) such as isoprene and monoterpenes. Although there are numerous studies investigating the formation of SOA from monoterpenes, there are few studies investigating monoterpene gas-phase chemistry. Using a regional chemical transport model with an extended representation of organic nitrate chemistry, we investigate the processes controlling the production and fate of monoterpene nitrates (MTNs) over the boreal forest of Canada. MTNs account for 5–12% of total oxidized nitrogen over the boreal forest, and production via NO[subscript 3] chemistry is more important than production via OH when the NO[subscript x] mixing ratio is greater than 75 pptv. The regional responses are investigated for two oxidation pathways of MTNs: one that returns NO[subscript x] to the atmosphere and one that converts MTNs into a nitrate that behaves like HNO[subscript 3]. The likely situation is in between, and these two assumptions bracket the uncertainty about this chemistry. In the case where the MTNs return NO[subscript x] after oxidation, their formation represents a net chemical NO[subscript x] loss that exceeds the net loss to peroxy nitrate formation. When oxidation of MTNs produces a molecule that behaves like HNO[subscript 3], HNO[subscript 3] and MTNs are nearly equal chemical sinks for NO[subscript x]. This uncertainty in the oxidative fate of MTNs results in changes in NO[subscript x] of 8–14%, in O[subscript 3] of up to 3%, and in OH of 3–6% between the two model simulations.United States. National Aeronautics and Space Administration (Grant NNX08AR13G)United States. National Aeronautics and Space Administration (Earth Systems Science Fellowship
Robust Estimation for Linear Panel Data Models
In different fields of applications including, but not limited to,
behavioral, environmental, medical sciences and econometrics, the use of panel
data regression models has become increasingly popular as a general framework
for making meaningful statistical inferences. However, when the ordinary least
squares (OLS) method is used to estimate the model parameters, presence of
outliers may significantly alter the adequacy of such models by producing
biased and inefficient estimates. In this work we propose a new, weighted
likelihood based robust estimation procedure for linear panel data models with
fixed and random effects. The finite sample performances of the proposed
estimators have been illustrated through an extensive simulation study as well
as with an application to blood pressure data set. Our thorough study
demonstrates that the proposed estimators show significantly better
performances over the traditional methods in the presence of outliers and
produce competitive results to the OLS based estimates when no outliers are
present in the data set
ENVIRONMENTAL SURVEILLANCE IN THE VINCINITY OF HANFORD FOR AUGUST, 1968
This report contains information related to radioactive materials in the Columbia River, the atmosphere, and selected foods for August, 1968, Measurements of the Columbia River flow rate, temperature, and chemical characteristics are also shown. Data for the previous twelve months is included
Domestic Rivalry and Export Performance: Theory and Evidence from International Airline Markets
The much-studied relationship between domestic rivalry and export performance consists of those supporting a national-champion rationale, and those supporting a rivalry rationale. While the empirical literature generally supports the positive effects of domestic rivalry, the national-champion rationale actually rests on firmer theoretical ground. We address this inconsistency by providing a theoretical framework that illustrates three paths via which domestic rivalry translates into enhanced international exports. Furthermore, empirical tests on the world airline industry elicit the existence of one particular path - an enhanced firm performance effect - that connects domestic rivalry with improved international exports
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