92,701 research outputs found
NASA technology utilization program: The small business market
Technology transfer programs were studied to determine how they might be more useful to the small business community. The status, needs, and technology use patterns of small firms are reported. Small business problems and failures are considered. Innovation, capitalization, R and D, and market share problems are discussed. Pocket, captive, and new markets are summarized. Small manufacturers and technology acquisition are discussed, covering external and internal sources, and NASA technology. Small business and the technology utilization program are discussed, covering publications and industrial applications centers. Observations and recommendations include small business market development and contracting, and NASA management technology
Model for Dissipative Highly Nonlinear Waves in Dry Granular Systems
A model is presented for the characterization of dissipative effects on
highly nonlinear waves in one-dimensional dry granular media. The model
includes three terms: Hertzian, viscoelastic, and a term proportional to the
square of the relative velocity of particles. The model outcomes are confronted
with different experiments where the granular system is subject to several
constraints for different materials. Excellent qualitative and quantitative
agreement between theory and experiments is found.Comment: Link to the Journal: http://prl.aps.org/abstract/PRL/v104/i11/e11800
Rapid optimization of multiple-burn rocket flights, 8 March 1968 - 8 March 1969
Iterative solution of boundary value problem for rapid optimization of multiple-burn rocket flight
Recent developments in the eikonal description of the breakup of exotic nuclei
The study of exotic nuclear structures, such as halo nuclei, is usually
performed through nuclear reactions. An accurate reaction model coupled to a
realistic description of the projectile is needed to correctly interpret
experimental data. In this contribution, we briefly summarise the assumptions
made within the modelling of reactions involving halo nuclei. We describe
briefly the Continuum-Discretised Coupled Channel method (CDCC) and the
Dynamical Eikonal Approximation (DEA) in particular and present a comparison
between them for the breakup of 15C on Pb at 68AMeV. We show the problem faced
by the models based on the eikonal approximation at low energy and detail a
correction that enables their extension down to lower beam energies. A new
reaction observable is also presented. It consists of the ratio between angular
distributions for two different processes, such as elastic scattering and
breakup. This ratio is completely independent of the reaction mechanism and
hence is more sensitive to the projectile structure than usual reaction
observables, which makes it a very powerful tool to study exotic structures far
from stability.Comment: Contribution to the proceedings of the XXI International School on
Nuclear Physics and Applications & the International Symposium on Exotic
Nuclei, dedicated to the 60th Anniversary of the JINR (Dubna) (Varna,
Bulgaria, 6-12 September 2015), 7 pages, 4 figure
Multiplpe Choice Minority Game With Different Publicly Known Histories
In the standard Minority Game, players use historical minority choices as the
sole public information to pick one out of the two alternatives. However,
publishing historical minority choices is not the only way to present global
system information to players when more than two alternatives are available.
Thus, it is instructive to study the dynamics and cooperative behaviors of this
extended game as a function of the global information provided. We numerically
find that although the system dynamics depends on the kind of public
information given to the players, the degree of cooperation follows the same
trend as that of the standard Minority Game. We also explain most of our
findings by the crowd-anticrowd theory.Comment: Extensively revised, to appear in New J Phys, 7 pages with 4 figure
Consumer Responses to Recent BSE Events
Recent bovine spongiform encephalopathy (BSE, a.k.a. mad cow disease) discoveries in Canadian and U.S. beef cattle have garnered significant media attention, which may have changed consumers’ meat-purchasing behavior. Consumer response is hypothesized and tested within a meat demand system in which response is measured using single-period dummy variables, longer-term dummy variables, and media indices that count positive and negative meat-industry articles. Parameters are estimated using retail scanner data, and cross-species price elasticities are calculated. Results suggest that the BSE events negatively impacted ground beef and chuck roasts, while positively impacting center-cut pork chop demand. Dummy variables explained the variation in meat-budget shares better than did media indices.Consumer/Household Economics,
Theory of adhesion: role of surface roughness
We discuss how surface roughness influence the adhesion between elastic
solids. We introduce a Tabor number which depends on the length scale or
magnification, and which gives information about the nature of the adhesion at
different length scales. We consider two limiting cases relevant for (a)
elastically hard solids with weak adhesive interaction (DMT-limit) and (b)
elastically soft solids or strong adhesive interaction (JKR-limit). For the
former cases we study the nature of the adhesion using different adhesive force
laws (, , where is the wall-wall separation). In
general, adhesion may switch from DMT-like at short length scales to JKR-like
at large (macroscopic) length scale. We compare the theory predictions to the
results of exact numerical simulations and find good agreement between theory
and the simulation results
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