10,234 research outputs found
Passive optical wind and turbulence detection system Patent
Passive optical wind and turbulence remote detection syste
Study of hot wire techniques in low density flows with high turbulence levels
Prediction of heat, mass, species, and momentum fluxes in a space vehicle and aerodynamic noise production by supersonic jet and rocket exhausts requires a predictability of the associated turbulence fields. The hot wire is a technique that will allow an experimental determination of turbulent properties
Applications of remote sensing to stream discharge predictions
A feasibility study has been initiated on the use of remote earth observations for augmenting stream discharge prediction for the design and/or operation of major reservoir systems, pumping systems and irrigation systems. The near-term objectives are the interpolation of sparsely instrumented precipitation surveillance networks and the direct measurement of water loss by evaporation. The first steps of the study covered a survey of existing reservoir systems, stream discharge prediction methods, gage networks and the development of a self-adaptive variation of the Kentucky Watershed model, SNOPSET, that includes snowmelt. As a result of these studies, a special three channel scanner is being built for a small aircraft, which should provide snow, temperature and water vapor maps for the spatial and temporal interpolation of stream gages
Optical crossed-beam investigation of local sound generation in jets
Cross correlation of optical signals from two light beam sound detectors for jet noise source localizatio
Noise elimination by piecewise cross correlation of photometer outputs
A piecewise cross correlation technique has been developed to analyze the outputs of remote detection devices. The purpose of this technique is to eliminate the noise from optical background fluctuations, from transmission fluctuations and from detectors by calculating the instantaneous product of the detector output and a reference signal. Each noise component causes positive and negative oscillations of the instantaneous product and may thus be cancelled by an integration of the instantaneous product. The resultant product mean values will then contain the desired information on the spatial and temporal variation of emission, absorption and scattering processes in the atmosphere
Axiomatization and Models of Scientific Theories
In this paper we discuss two approaches to the axiomatization of scien- tific theories in the context of the so called semantic approach, according to which (roughly) a theory can be seen as a class of models. The two approaches are associated respectively to Suppes’ and to da Costa and Chuaqui’s works. We argue that theories can be developed both in a way more akin to the usual mathematical practice (Suppes), in an informal set theoretical environment, writing the set theoretical predicate in the language of set theory itself or, more rigorously (da Costa and Chuaqui), by employing formal languages that help us in writing the postulates to define a class of structures. Both approaches are called internal, for we work within a mathematical framework, here taken to be first-order ZFC. We contrast these approaches with an external one, here discussed briefly. We argue that each one has its strong and weak points, whose discussion is relevant for the philosophical foundations of science
On cross-beam monitoring of atmospheric winds and turbulence with two orbiting telescopes
Crossed beam monitoring of atmospheric winds and turbulence with two orbiting astronomical telescopes mounted on single spacecraf
Kinetic energy cascades in quasi-geostrophic convection in a spherical shell
We consider triadic nonlinear interaction in the Navier-Stokes equation for
quasi-geostrophic convection in a spherical shell. This approach helps
understanding the origin of kinetic energy transport in the system and the
particular scheme of mode interaction, as well as the locality of the energy
transfer. The peculiarity of convection in the sphere, concerned with
excitation of Rossby waves, is considered. The obtained results are compared
with our previous study in Cartesian geometry
Study of Hg vacancies in (Hg,Cd)Te after THM growth and post-growth annealing by positron annihilation
Positron lifetime measurements have been performed to study vacancy defects in Hg0.78Cd0.22Te. Post-growth annealing under various Hg vapour pressure conditions have been used to create a well-defined number of Hg vacancies. The sensitivity range of the positron annihilation method was found to be 1015 < cHgvac<1018 cm-3. The obtained experience has been used to investigate THM-grown single crystals. The measured longitudinal and radial dependence of the vacancy concentration can be explained by the temperature profile in the grown (Hg,Cd)Te ingots
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