2,387 research outputs found
Multiple jet study data correlations
Correlations are presented which allow determination of penetration and mixing of multiple cold air jets injected normal to a ducted subsonic heated primary air stream. Correlations were obtained over jet-to-primary stream momentum flux ratios of 6 to 60 for locations from 1 to 30 jet diameters downstream of the injection plane. The range of geometric and operating variables makes the correlations relevant to gas turbine combustors. Correlations were obtained for the mixing efficiency between jets and primary stream using an energy exchange parameter. Also jet centerplane velocity and temperature trajectories were correlated and centerplane dimensionless temperature distributions defined. An assumption of a Gaussian vertical temperature distribution at all stations is shown to result in a reasonable temperature field model. Data are presented which allow comparison of predicted and measured values over the range of conditions specified above
Conceptual design and analysis of orbital cryogenic liquid storage and supply systems
A wide variety of orbital cryogenic liquid storage and supply systems are defined in NASA and DOD long-range plans. These systems include small cooling applications, large chemical and electrical orbit transfer vehicles and supply tankers. All have the common requirements of low-g fluid management to accomplish gas-free liquid expulsion and efficient thermal control to manage heat leak and tank pressure. A preliminary design study was performed to evaluate tanks ranging from 0.6 to 37.4 cu m (22 to 1320 cu ft). Liquids of interest were hydrogen, oxygen, methane, argon and helium. Conceptual designs were generated for each tank system and fluid dynamic, thermal and structural analyses were performed for Shuttle compatible operations. Design trades considered the paradox of conservative support structure and minimum thermal input. Orbital performance and weight data were developed, and a technology evaluation was completed
Passive Retention/Expulsion Methods for Subcritical Storage of Cryogens
Development of passive retention/expulsion system for subcritical storage of cryogenic material during low gravity situation
V2:Performance of the solid deuterium ultra-cold neutron source at the pulsed reactor TRIGA Mainz
The performance of the solid deuterium ultra-cold neutron source at the
pulsed reactor TRIGA Mainz with a maximum peak energy of 10 MJ is described.
The solid deuterium converter with a volume of V=160 cm3 (8 mol), which is
exposed to a thermal neutron fluence of 4.5x10^13 n/cm2, delivers up to 550 000
UCN per pulse outside of the biological shield at the experimental area. UCN
densities of ~ 10/cm3 are obtained in stainless steel bottles of V ~ 10 L
resulting in a storage efficiency of ~20%. The measured UCN yields compare well
with the predictions from a Monte Carlo simulation developed to model the
source and to optimize its performance for the upcoming upgrade of the TRIGA
Mainz into a user facility for UCN physics.Comment: 23 pages, 8 figure
Produção de biomassa e de sementes, qualidade bromatológica e fixação de nitrogênio em feijão-sopinha.
Resumos do VIII Congresso Brasileiro de Agroecologia - Porto Alegre/RS - 25 a 28/11/2013
As variedades crioulas de cebola e o potencial de uso em sistemas agroecologicos.
Objetivou-se descrever os sistemas de cultivo de cebola tradicionais e avaliar o potencial dos genótipos crioulos para sistemas agroecológicos
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