634 research outputs found

    International Energy Problems And Environmental Policy

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    Energy — the ability to work — is essential to our economic welfare, productivity and our living standards. Before the recent oil embargo, it was said that a gallon of oil (or its equivalent in other forms of energy) provides power for the economic activity associated with two dollars of gross national product. However, the raw material cost of that oil at the point of production was only 7 percent of this gross national product value. In the aftermath of the embargo, there is grave concern that the United States will become overly dependent on imports of oil, and will not be able to meet its energy requirements without which the nation will see its national income drop sharply. Unfortunately we share this energy predicament with most industrialized countries. Primary sources such as hydro power, petroleum, natural gas, solid coal, and uranium are insufficient to meet future demands of the World economy, unless other primary nonfossil fuel can be developed. The uses of energy also have some adverse environmental impacts associated with generation of energy (oil drilling, coal mining, water storage) , delivery (oil spills, transmission lines, exhaust fumes), and misapplications (glare, noise, debris). In large part, the adverse side effects are a sign of inefficiency. Environmental enhancement will gain as efficiencies improve, as technology develops new sources, such as hydrogen or solar sources, and as customers accept the higher costs of cleaner fuels, such as synthetic gas

    An investigation of some statistical methods of evaluating the reliability of results of laboratory tests of petrolem products.

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    This thesis document was issued under the authority of another institution, not NPS. At the time it was written, a copy was added to the NPS Library Collection for reasons not now known. It has been included in the digital archive for its historical value to NPS. Not believed to be a CIVINS (Civilian Institutions) title.Quality surveillance of military petroleum products is the aggregate of measures to be applied to determine and maintain their quality. Quality surveillance programs are conducted in order that required petroleum products will be available in a condition suitable for immediate use. Their ultimate purpose is: (1) to insure that no life is ever lost or equipment damaged or destroyed through the use of contaminated or deteriorated petroleum products, and (2) to promote economy by minimizing the necessity of surveying or reclaiming any petroleum products because of contamination or deterioration. The success of any such program is dependent upon several factors, not the least of which is the maintenance of the highest standards of reliability in the testing laboratories.http://www.archive.org/details/investigationofs00deutUnited States Nav

    Apparent Superluminal Behavior

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    The apparent superluminal propagation of electromagnetic signals seen in recent experiments is shown to be the result of simple and robust properties of relativistic field equations. Although the wave front of a signal passing through a classically forbidden region can never move faster than light, an attenuated replica of the signal is reproduced ``instantaneously'' on the other side of the barrier. The reconstructed signal, causally connected to the forerunner rather than the bulk of the input signal, appears to move through the barrier faster than light.Comment: 8 pages, no figure

    Astrometric Control of the Inertiality of the Hipparcos Catalog

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    Based on the most complete list of the results of an individual comparison of the proper motions for stars of various programs common to the Hipparcos catalog, each of which is an independent realization of the inertial reference frame with regard to stellar proper motions, we redetermined the vector ω\omega of residual rotation of the ICRS system relative to the extragalactic reference frame. The equatorial components of this vector were found to be the following: ωx=+0.04±0.15\omega_x = +0.04\pm 0.15 mas yr1^{-1}, ωy=+0.18±0.12\omega_y = +0.18\pm 0.12 mas yr1^{-1}, and ωz=0.35±0.09\omega_z = -0.35\pm 0.09 mas yr1^{-1}.Comment: 8 pages, 1 figur

    Hawking Radiation on an Ion Ring in the Quantum Regime

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    This paper discusses a recent proposal for the simulation of acoustic black holes with ions. The ions are rotating on a ring with an inhomogeneous, but stationary velocity profile. Phonons cannot leave a region, in which the ion velocity exceeds the group velocity of the phonons, as light cannot escape from a black hole. The system is described by a discrete field theory with a nonlinear dispersion relation. Hawking radiation is emitted by this acoustic black hole, generating entanglement between the inside and the outside of the black hole. We study schemes to detect the Hawking effect in this setup.Comment: 42 pages (one column), 17 figures, published revised versio

    Equivalence-Invariant Algebraic Provenance for Hyperplane Update Queries

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    The algebraic approach for provenance tracking, originating in the semiring model of Green et. al, has proven useful as an abstract way of handling metadata. Commutative Semirings were shown to be the "correct" algebraic structure for Union of Conjunctive Queries, in the sense that its use allows provenance to be invariant under certain expected query equivalence axioms. In this paper we present the first (to our knowledge) algebraic provenance model, for a fragment of update queries, that is invariant under set equivalence. The fragment that we focus on is that of hyperplane queries, previously studied in multiple lines of work. Our algebraic provenance structure and corresponding provenance-aware semantics are based on the sound and complete axiomatization of Karabeg and Vianu. We demonstrate that our construction can guide the design of concrete provenance model instances for different applications. We further study the efficient generation and storage of provenance for hyperplane update queries. We show that a naive algorithm can lead to an exponentially large provenance expression, but remedy this by presenting a normal form which we show may be efficiently computed alongside query evaluation. We experimentally study the performance of our solution and demonstrate its scalability and usefulness, and in particular the effectiveness of our normal form representation

    Magnetic Resonance

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    Contains research objectives and reports on three research projects

    Microscopic Derivation of Non-Markovian Thermalization of a Brownian Particle

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    In this paper, the first microscopic approach to the Brownian motion is developed in the case where the mass density of the suspending bath is of the same order of magnitude as that of the Brownian (B) particle. Starting from an extended Boltzmann equation, which describes correctly the interaction with the fluid, we derive systematicaly via the multiple time-scale analysis a reduced equation controlling the thermalization of the B particle, i.e. the relaxation towards the Maxwell distribution in velocity space. In contradistinction to the Fokker-Planck equation, the derived new evolution equation is non-local both in time and in velocity space, owing to correlated recollision events between the fluid and particle B. In the long-time limit, it describes a non-markovian generalized Ornstein-Uhlenbeck process. However, in spite of this complex dynamical behaviour, the Stokes-Einstein law relating the friction and diffusion coefficients is shown to remain valid. A microscopic expression for the friction coefficient is derived, which acquires the form of the Stokes law in the limit where the mean-free in the gas is small compared to the radius of particle B.Comment: 28 pages, no figure, submitted to Journal of Statistical Physic

    NMR Simulation of an Eight-State Quantum System

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    The propagation of excitation along a one-dimensional chain of atoms is simulated by means of NMR. The physical system used as an analog quantum computer is a nucleus of 133-Cs (spin 7/2) in a liquid crystalline matrix. The Hamiltonian of migration is simulated by using a special 7-frequency pulse, and the dynamics is monitored by following the transfer of population from one of the 8 spin energy levels to the other.Comment: 10 pages, 3 figure

    On Multipartite Pure-State Entanglement

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    We show that pure states of multipartite quantum systems are multiseparable (i.e. give separable density matrices on tracing any party) if and only if they have a generalized Schmidt decomposition. Implications of this result for the quantification of multipartite pure-state entanglement are discussed. Further, as an application of the techniques used here, we show that any purification of a bipartite PPT bound entangled state is tri-inseparable, i.e. has none of its three bipartite partial traces separable.Comment: 8 Pages ReVTeX, 4 figures (eps); v2: Revised terminology, added two references and other minor changes; v3: Minor changes, added two references, added author's middle initial; v4: One footnote remove
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