1,531 research outputs found
Composite powerplant and shroud therefor Patent
Shrouded composite propulsion system configuratio
Integral coolant channels supply made by melt-out method
Melt-out method of constructing strong, pressure-tight fluid coolant channels for chambers is accomplished by cementing pins to the surface and by depositing a melt-out material on the surface followed by two layers of epoxy-resin impregnated glass fibers. The structure is heated to melt out the low-melting alloy
Attitude and propellant flow control system and method Patent
Attitude and propellant flow control system for liquid propellant rocket vehicle
A preliminary systems-engineering study of an advanced nuclear-electrolytic hydrogen-production facility
An advanced nuclear-electrolytic hydrogen-production facility concept was synthesized at a conceptual level with the objective of minimizing estimated hydrogen-production costs. The concept is a closely-integrated, fully-dedicated (only hydrogen energy is produced) system whose components and subsystems are predicted on ''1985 technology.'' The principal components are: (1) a high-temperature gas-cooled reactor (HTGR) operating a helium-Brayton/ammonia-Rankine binary cycle with a helium reactor-core exit temperature of 980 C, (2) acyclic d-c generators, (3) high-pressure, high-current-density electrolyzers based on solid-polymer electrolyte technology. Based on an assumed 3,000 MWt HTGR the facility is capable of producing 8.7 million std cu m/day of hydrogen at pipeline conditions, 6,900 kPa. Coproduct oxygen is also available at pipeline conditions at one-half this volume. It has further been shown that the incorporation of advanced technology provides an overall efficiency of about 43 percent, as compared with 25 percent for a contemporary nuclear-electric plant powering close-coupled contemporary industrial electrolyzers
Hydrogen-via-electricity concept. Critique report
The hydrogen-via-electricity (HvE) concept is the prospective use of hydrogen fuel produced electrolytically from the electric utility grid as a means of responding to conventional fuels shortages. The two sets of comments and critiques of this concept solicited from the Government/Government contractor group and from the electric utility companies are presented
Solar/hydrogen systems assessment. Volume 1: Solar/hydrogen systems for the 1985 - 2000 time frame
Opportunities for commercialization of systems capable of producing hydrogen from solar energy were studied. The hydrogen product costs that might be achieved by the four selected candidate systems was compared with the pricing structure and practices of the commodity gas market. Subsequently, product cost and market price match was noted to exist in the small user sector of the hydrogen marketplace. Barriers to and historical time lags in, commercialization of new technologies are reviewed. Recommendations for development and demonstration programs designed to accelerate the commercialization of the candidate systems are presented
Study of Systems and Technology for Liquid Hydrogen Production Independent of Fossil Fuels
Based on Kennedy Space Center siting and logistics requirements and the nonfossil energy resources at the Center, a number of applicable technologies and system candidates for hydrogen production were identified and characterized. A two stage screening of these technologies in the light of specific criteria identified two leading candidates as nonfossil system approaches. Conceptual design and costing of two solar-operated, stand alone systems, one photovoltaic based on and the other involving the power tower approach reveals their technical feasibility as sited as KSC, and the potential for product cost competitiveness with conventional supply approaches in the 1990 to 1210 time period. Conventional water hydrolysis and hydrogen liquefaction subsystems are integrated with the solar subsystems
Necrotic tumor growth: an analytic approach
The present paper deals with a free boundary problem modeling the growth
process of necrotic multi-layer tumors. We prove the existence of flat
stationary solutions and determine the linearization of our model at such an
equilibrium. Finally, we compute the solutions of the stationary linearized
problem and comment on bifurcation.Comment: 14 pages, 3 figure
Toward a complete theory for predicting inclusive deuteron breakup away from stability
We present an account of the current status of the theoretical treatment of
inclusive reactions in the breakup-fusion formalism, pointing to some
applications and making the connection with current experimental capabilities.
Three independent implementations of the reaction formalism have been recently
developed, making use of different numerical strategies. The codes also
originally relied on two different but equivalent representations, namely the
prior (Udagawa-Tamura, UT) and the post (Ichimura-Austern-Vincent, IAV)
representations.
The different implementations have been benchmarked, and then applied to the
Ca isotopic chain. The neutron-Ca propagator is described in the Dispersive
Optical Model (DOM) framework, and the interplay between elastic breakup (EB)
and non-elastic breakup (NEB) is studied for three Ca isotopes at two different
bombarding energies. The accuracy of the description of different reaction
observables is assessed by comparing with experimental data of on
Ca. We discuss the predictions of the model for the extreme case of
an isotope (Ca) currently unavailable experimentally, though possibly
available in future facilities (nominally within production reach at FRIB). We
explore the use of reactions as surrogates for processes,
by using the formalism to describe the compound nucleus formation in a
reaction as a function of excitation energy, spin, and parity.
The subsequent decay is then computed within a Hauser-Feshbach formalism.
Comparisons between the and induced gamma decay
spectra are discussed to inform efforts to infer neutron captures from
reactions. Finally, we identify areas of opportunity for future
developments, and discuss a possible path toward a predictive reaction theory
Right-invariant Sobolev metrics of fractional order on the diffeomorphism group of the circle
In this paper, we study the geodesic flow of a right-invariant metric induced
by a general Fourier multiplier on the diffeomorphism group of the circle and
on some of its homogeneous spaces. This study covers in particular
right-invariant metrics induced by Sobolev norms of fractional order. We show
that, under a certain condition on the symbol of the inertia operator (which is
satisfied for the fractional Sobolev norm for ), the
corresponding initial value problem is well-posed in the smooth category and
that the Riemannian exponential map is a smooth local diffeomorphism.
Paradigmatic examples of our general setting cover, besides all traditional
Euler equations induced by a local inertia operator, the Constantin-Lax-Majda
equation, and the Euler-Weil-Petersson equation.Comment: 40 pages. Corrected typos and improved redactio
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