7,818 research outputs found
A reliable liquid helium detector
Detector and indicator system, utilizing commercial perforated germanium cryogenic thermometer as level sensor containing adjustable level discriminator with indicators, operates reliably over pressure range from 50 to 900 mm Hg without electronic adjustments
Advanced Earth-to-orbit propulsion technology program overview: Impact of civil space technology initiative
The NASA Earth-to-Orbit (ETO) Propulsion Technology Program is dedicated to advancing rocket engine technologies for the development of fully reusable engine systems that will enable space transportation systems to achieve low cost, routine access to space. The program addresses technology advancements in the areas of engine life extension/prediction, performance enhancements, reduced ground operations costs, and in-flight fault tolerant engine operations. The primary objective is to acquire increased knowledge and understanding of rocket engine chemical and physical processes in order to evolve more realistic analytical simulations of engine internal environments, to derive more accurate predictions of steady and unsteady loads, and using improved structural analyses, to more accurately predict component life and performance, and finally to identify and verify more durable advanced design concepts. In addition, efforts were focused on engine diagnostic needs and advances that would allow integrated health monitoring systems to be developed for enhanced maintainability, automated servicing, inspection, and checkout, and ultimately, in-flight fault tolerant engine operations
Financial Performance Value-Added Dairy Operations in New York, Vermont and Wisconsin
Federal, state and local governments have funded various efforts to support value added agriculture, often implicitly assuming that the enterprises would be profitable and that the transition from commodity producer to producer-processor-marketer-distributor would be relatively easy. Some analysts (e.g., Streeter and Bills; 2003a, 2003b) have questioned both of these assumptions, noting that available aggregate data do not allow assessment of the financial performance of value-added enterprises. Our study collected detailed financial information from 27 value-added dairy enterprises with cows, goats or sheep in three states. These businesses processed and marketed cheese, fluid milk products and yogurt; 17 had begun processing during the previous three years. The financial information was used to develop income statements and balance sheets for both the milk production and the dairy processing and marketing enterprises. Our results suggest that value-added dairy is not a panacea: despite much higher revenues per unit milk produced or processed, mean net income for the processing enterprise and for the combined milk production and processing business were modest at best and often negative. More than half of the on-farm processors had negative net incomes from processing, and seven processing enterprises had negative net worth. On average, returns per cwt milk processed were 209 per cwt (for cow and goat/sheep milk producers, respectively) lower than the full economic costs of production and processing.small-scale dairy processing, value added, financial performance, profitability, Agricultural Finance,
Characterizations of rings and modules by means of lattices.
PhDIn this thesis we study the relationship between the lattice of
submodules and the algebraic structure of a module. The key remark
in our study will be the fact that the homomorphisms between two
independent submadules of a module can be 'represented' by elements of
its lattice of submoduleso Exploiting this fact we show that the
endomorphism ring of a module which is the direct sum of more than three
isomorphic submodules is determined up to isomorphism by its lattice of
submodules.
Lattice isomorphisms arise naturally in two ways, viz., through
category equivalences and semi-linear isomorphisms. Any lattice
isomorphism between a free module of infinite rank and a module containing
at least one free submodule is shown to be induced by a category
equivalence. This result is used to give new characterizations of
Morita equivalence,
If certain mild conditions are satisfied a lattice isomorphism
between a free module of rank >3 and a faithful module is shown to give
rise to a semi-linear isomorphism between the modules* If both nodules
are free of rank n>3 then the question of whether there is a semi-linear
isomorphism between them is equivalent to asking when an isomorphism.
of matrix rings Rn Cý!! Sn implies a ring isomorphism R2ý S.
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Wo study rings R with this property for any n and any ring S.
The following are shown to be of this type (1) commutative rings
(2) p-trivial rings (3) matrix rings over strongly regular rings
left self-injective rings.
Applying these results we give new examples of regular rings
which uniquely co-ordinatize a complemented modular lattice of otder
In particular we show such a co-ordinatization is always unique to
within injective hull
Extended Bose-Hubbard model with incompressible states at fractional numbers
The Bose-Hubbard model is extended to include nearest and far neighbor
interactions and is related to the fractional quantum Hall effect (FQHE). Both
models may be studied in optical lattices with quantum gases. The ground state
is calculated for the extended Bose-Hubbard model with strong repulsive
interactions (weak hopping). Incompressible Mott insulator states are found at
rational filling fractions compatible with the principal and secondary FQHE
filling fractions of the lowest Landau levels observed experimentally. It is
discussed to which extent these states at fractional filling survive or
undergoes a Mott insulator transition to a superfluid as hopping terms are
included.Comment: Revised version, to appear in PR
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