374 research outputs found

    Interstitial compounds as fuel cell catalysts - Their preparative techniques and electrochemical testing

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    Preparation and electrochemical testing methods for fuel cell catalysts using interstitial compound

    Development of an improved oxygen electrode for use in alkaline H2-O2 fuel cells Quarterly report, Oct. 1 - Dec. 31, 1966

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    Interstitial compounds of transition elements prepared for improving oxygen electrode in alkaline hydrox fuel cel

    Development of an improved oxygen electrode for use in alkaline H2-O2 fuel cells Quarterly report, Apr. 1 - Jun. 30, 1967

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    Preparation of institial compounds of transition metals for hydrogen oxygen fuel cell cathode

    Planar Embeddings with Small and Uniform Faces

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    Motivated by finding planar embeddings that lead to drawings with favorable aesthetics, we study the problems MINMAXFACE and UNIFORMFACES of embedding a given biconnected multi-graph such that the largest face is as small as possible and such that all faces have the same size, respectively. We prove a complexity dichotomy for MINMAXFACE and show that deciding whether the maximum is at most kk is polynomial-time solvable for k4k \leq 4 and NP-complete for k5k \geq 5. Further, we give a 6-approximation for minimizing the maximum face in a planar embedding. For UNIFORMFACES, we show that the problem is NP-complete for odd k7k \geq 7 and even k10k \geq 10. Moreover, we characterize the biconnected planar multi-graphs admitting 3- and 4-uniform embeddings (in a kk-uniform embedding all faces have size kk) and give an efficient algorithm for testing the existence of a 6-uniform embedding.Comment: 23 pages, 5 figures, extended version of 'Planar Embeddings with Small and Uniform Faces' (The 25th International Symposium on Algorithms and Computation, 2014

    An Application Of The Conceptual Model Of Service Quality To Independent Auditing Services

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    Auditing’s expectations gap has been documented over the last 35 years beginning with Liggio (1974) who initially coined and defined the term.  Porter’s (1991) and Australian Education Research’s (2009) models explored this gap.  However, these models don’t recognize the auditors’ three customer groups: auditees, the public, and regulatory agencies.  Additionally, these models don’t consider communication’s role between auditors and their customer groups.  The  following discussion applies the service quality model (SERVQUAL) developed by Parasuraman, Zeithaml and Berry (1988 and 1991) to the audit expectation gap and makes recommendations for researching the components, causes, effects of and solutions to the auditing expectations. This model identifies expectation gaps between the service provider (the auditor) and its customers including the auditee, the financial statement user, and the regulatory agencies.  Nyeck, Morales, Ladhari, and Pons (2002, p. 102) concluded in a review article of SERVQUAL research”. . .the SERVQUAL model remains the most complete attempt to conceptualize and measure service quality.&rdquo

    Изучение структуры цинктитановых боросиликатных стекол по данным рассеяния рентгеновских лучей под малыми углами

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    В статті вивчено мікронеоднорідну будову цинктитанових боросилікатних стекол та процесів фазового розділу в них за даним розсіяння нейтронів під малими кутами. Зроблено висновок про характер розподілення часток, що виділяються за розмірами, які змінюються в дослідних стеклах в залежності від вмісту в них TiO₂ та ZnO. Встановлено вплив наявності мікронеоднорідностей після варки на характер їх фазовогорозподілення.In paper the micronon-uniform structure zinc-titanium borosilicate glass and processes of phase separation in them according to diffusing under vanishing angles of neutrons is investigated. It is drawn a In paper the micronon-uniform structure zinc-titanium borosilicate glass and processes of phase separation in them according to diffusing under vanishing angles of neutrons is investigated. It is drawn a leading-out on distribution of depositing corpuscles character on sizes which changes in studied glasses depending on the contents in them TiO₂ and ZnO. Effect of presence micro micronon-uniforms after melting on character of their phase separationis established

    Exact Solution Methods for the kk-item Quadratic Knapsack Problem

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    The purpose of this paper is to solve the 0-1 kk-item quadratic knapsack problem (kQKP)(kQKP), a problem of maximizing a quadratic function subject to two linear constraints. We propose an exact method based on semidefinite optimization. The semidefinite relaxation used in our approach includes simple rank one constraints, which can be handled efficiently by interior point methods. Furthermore, we strengthen the relaxation by polyhedral constraints and obtain approximate solutions to this semidefinite problem by applying a bundle method. We review other exact solution methods and compare all these approaches by experimenting with instances of various sizes and densities.Comment: 12 page

    A Nearly Linear-Time PTAS for Explicit Fractional Packing and Covering Linear Programs

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    We give an approximation algorithm for packing and covering linear programs (linear programs with non-negative coefficients). Given a constraint matrix with n non-zeros, r rows, and c columns, the algorithm computes feasible primal and dual solutions whose costs are within a factor of 1+eps of the optimal cost in time O((r+c)log(n)/eps^2 + n).Comment: corrected version of FOCS 2007 paper: 10.1109/FOCS.2007.62. Accepted to Algorithmica, 201

    Portfolio selection problems in practice: a comparison between linear and quadratic optimization models

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    Several portfolio selection models take into account practical limitations on the number of assets to include and on their weights in the portfolio. We present here a study of the Limited Asset Markowitz (LAM), of the Limited Asset Mean Absolute Deviation (LAMAD) and of the Limited Asset Conditional Value-at-Risk (LACVaR) models, where the assets are limited with the introduction of quantity and cardinality constraints. We propose a completely new approach for solving the LAM model, based on reformulation as a Standard Quadratic Program and on some recent theoretical results. With this approach we obtain optimal solutions both for some well-known financial data sets used by several other authors, and for some unsolved large size portfolio problems. We also test our method on five new data sets involving real-world capital market indices from major stock markets. Our computational experience shows that, rather unexpectedly, it is easier to solve the quadratic LAM model with our algorithm, than to solve the linear LACVaR and LAMAD models with CPLEX, one of the best commercial codes for mixed integer linear programming (MILP) problems. Finally, on the new data sets we have also compared, using out-of-sample analysis, the performance of the portfolios obtained by the Limited Asset models with the performance provided by the unconstrained models and with that of the official capital market indices

    Measurement of neutrino and antineutrino neutral-current quasielasticlike interactions on oxygen by detecting nuclear deexcitation γ rays

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    Neutrino- A nd antineutrino-oxygen neutral-current quasielasticlike interactions are measured at Super-Kamiokande using nuclear deexcitation γ rays to identify signal-like interactions in data from a 14.94(16.35)×1020 protons-on-target exposure of the T2K neutrino (antineutrino) beam. The measured flux-averaged cross sections on oxygen nuclei are âσν-NCQE
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