4,711 research outputs found

    Ecology and thermal inactivation of microbes in and on interplanetary space vehicle components Quarterly progress report, 1 Apr. - 30 Jun. 1970

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    Ecology and thermal inactivation of microbes in and on interplanetary space vehicle component

    Climate Change and Dam Owner Liability in Rhode Island

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    Increasing precipitation associated with climate change is affecting dam operation and hazards in Rhode Island. Flooding caused by increased precipitation or extreme weather events can cause dam failure or upstream or downstream flooding, resulting in loss of life and property. These losses can result in liability, which may vary based on the dam owner and its purpose. This study assists dam owners and the public in understanding the potential liabilities that may arise as a result of flooding from extreme weather events. Section one provides a background of dam hazards in Rhode Island in the context of climate change. Section two introduces the statutory, common law, and constitutional claims that may be brought against a dam owner after a flood. Section three applies these potential liabilities to illustrate how they may apply to different types of dams and dam owners. Section four evaluates Rhode Island law in the context of state laws from the northeast region, focusing on the application of statutory liability, strict liability and negligence standards, and liability for drawdown

    Backpack carrier Patent

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    Backpack carrier with retractable legs suitable for lunar exploration and convertible to rescue vehicl

    Ecology and thermal inactivation of microbes in and on interplanetary space vehicle components Quarterly progress report, 1 Jul. - 30 Sep. 1969

    Get PDF
    Ecology and thermal inactivation of microbes in and on interplanetary space vehicle component

    Families of Graphs with W_r({G},q) Functions That Are Nonanalytic at 1/q=0

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    Denoting P(G,q)P(G,q) as the chromatic polynomial for coloring an nn-vertex graph GG with qq colors, and considering the limiting function W({G},q)=limnP(G,q)1/nW(\{G\},q) = \lim_{n \to \infty}P(G,q)^{1/n}, a fundamental question in graph theory is the following: is Wr({G},q)=q1W({G},q)W_r(\{G\},q) = q^{-1}W(\{G\},q) analytic or not at the origin of the 1/q1/q plane? (where the complex generalization of qq is assumed). This question is also relevant in statistical mechanics because W({G},q)=exp(S0/kB)W(\{G\},q)=\exp(S_0/k_B), where S0S_0 is the ground state entropy of the qq-state Potts antiferromagnet on the lattice graph {G}\{G\}, and the analyticity of Wr({G},q)W_r(\{G\},q) at 1/q=01/q=0 is necessary for the large-qq series expansions of Wr({G},q)W_r(\{G\},q). Although WrW_r is analytic at 1/q=01/q=0 for many {G}\{G\}, there are some {G}\{G\} for which it is not; for these, WrW_r has no large-qq series expansion. It is important to understand the reason for this nonanalyticity. Here we give a general condition that determines whether or not a particular Wr({G},q)W_r(\{G\},q) is analytic at 1/q=01/q=0 and explains the nonanalyticity where it occurs. We also construct infinite families of graphs with WrW_r functions that are non-analytic at 1/q=01/q=0 and investigate the properties of these functions. Our results are consistent with the conjecture that a sufficient condition for Wr({G},q)W_r(\{G\},q) to be analytic at 1/q=01/q=0 is that {G}\{G\} is a regular lattice graph Λ\Lambda. (This is known not to be a necessary condition).Comment: 22 pages, Revtex, 4 encapsulated postscript figures, to appear in Phys. Rev.

    Ground State Entropy of Potts Antiferromagnets: Bounds, Series, and Monte Carlo Measurements

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    We report several results concerning W(Λ,q)=exp(S0/kB)W(\Lambda,q)=\exp(S_0/k_B), the exponent of the ground state entropy of the Potts antiferromagnet on a lattice Λ\Lambda. First, we improve our previous rigorous lower bound on W(hc,q)W(hc,q) for the honeycomb (hc) lattice and find that it is extremely accurate; it agrees to the first eleven terms with the large-qq series for W(hc,q)W(hc,q). Second, we investigate the heteropolygonal Archimedean 4824 \cdot 8^2 lattice, derive a rigorous lower bound, on W(482,q)W(4 \cdot 8^2,q), and calculate the large-qq series for this function to O(y12)O(y^{12}) where y=1/(q1)y=1/(q-1). Remarkably, these agree exactly to all thirteen terms calculated. We also report Monte Carlo measurements, and find that these are very close to our lower bound and series. Third, we study the effect of non-nearest-neighbor couplings, focusing on the square lattice with next-nearest-neighbor bonds.Comment: 13 pages, Latex, to appear in Phys. Rev.

    A procedure for the change point problem in parametric models based on phi-divergence test-statistics

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    This paper studies the change point problem for a general parametric, univariate or multivariate family of distributions. An information theoretic procedure is developed which is based on general divergence measures for testing the hypothesis of the existence of a change. For comparing the accuracy of the new test-statistic a simulation study is performed for the special case of a univariate discrete model. Finally, the procedure proposed in this paper is illustrated through a classical change-point example

    An adaptive prefix-assignment technique for symmetry reduction

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    This paper presents a technique for symmetry reduction that adaptively assigns a prefix of variables in a system of constraints so that the generated prefix-assignments are pairwise nonisomorphic under the action of the symmetry group of the system. The technique is based on McKay's canonical extension framework [J.~Algorithms 26 (1998), no.~2, 306--324]. Among key features of the technique are (i) adaptability---the prefix sequence can be user-prescribed and truncated for compatibility with the group of symmetries; (ii) parallelizability---prefix-assignments can be processed in parallel independently of each other; (iii) versatility---the method is applicable whenever the group of symmetries can be concisely represented as the automorphism group of a vertex-colored graph; and (iv) implementability---the method can be implemented relying on a canonical labeling map for vertex-colored graphs as the only nontrivial subroutine. To demonstrate the practical applicability of our technique, we have prepared an experimental open-source implementation of the technique and carry out a set of experiments that demonstrate ability to reduce symmetry on hard instances. Furthermore, we demonstrate that the implementation effectively parallelizes to compute clusters with multiple nodes via a message-passing interface.Comment: Updated manuscript submitted for revie
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