287 research outputs found

    ANALYSIS OF SMALL BUSINESS PARTICIPATION IN ONLINE MARKETPLACES

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    As commercial e-commerce portals continue to grow in popularity among the acquisition workforce, it is imperative that the federal government ensures companies of all business sizes are able to compete fairly. This research examines the current framework of platform providers and makes recommendations on how small businesses can be better utilized without sacrificing competition, while keeping an extensive industry base and receiving best value for both the taxpayer and warfighter.Civilian, Department of the NavyCivilian, Department of the NavyCivilian, Department of the NavyApproved for public release. Distribution is unlimited

    Vacancy Tuning in Li,V-Substituted Lyonsites

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    © 2020 Taylor & Francis Group, LLC. The lyonsite structure, characterized by the formula A 4 M 3O12, is a relatively understudied tunneled crystal structure. This host structure is known to be compositionally flexible, able to incorporate a number of cations in various oxidation states into the A site. In the parent compound Co3.75V1.5Mo1.5O12, it is apparent that a stoichiometric vacancy of 0.25 is unavoidable as a result of Coulombic repulsion. This work focuses on the systematic elimination of vacancies by chemically introducing guest Li ions while maintaining host integrity. A full solid solution was found to exist with the formula □0.25–1/8xLi x Co3.75–7/8xV1.5–3/4xMo1.5+3/4xO12 (0 ≤ x ≤ 2), terminating at the known end member Li2Co2Mo3O12. Lattice refinements on PXRD data confirmed the isostructural nature of the whole series, and detailed structural analysis revealed that competition between Li and Co in the same crystallographic site is unequal, with Li exhibiting a stronger site preference for larger interstitial sites. Diffuse reflectance analysis revealed that the optical band gap is directly tunable with x, and supporting structure-property relationships were also explored via magnetometry and dielectric measurements

    Leggett Modes Accompanying Crystallographic Phase Transitions

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    Higgs and Goldstone modes, well known in high-energy physics, have been realized in a number of condensed matter physics contexts, including superconductivity and magnetism. The Goldstone-Higgs concept is also applicable to and gives rise to new insight on structural phase transitions. Here, we show that the Leggett mode, a collective mode observed in multiband superconductors, also has an analog in crystallographic phase transitions. Such structural Leggett modes can occur in the phase channel as in the original work of Leggett [Prog. Theor. Phys. 36, 901 (1966)PTPKAV0033-068X10.1143/PTP.36.901]. That is, they are antiphase Goldstone modes (antiphasons). In addition, a new collective mode can also occur in the amplitude channel, an out-of phase (antiphase) Higgs mode, that should be observable in multiband superconductors as well. We illustrate the existence and properties of these structural Leggett modes using the example of the pyrochlore relaxor ferroelectric Cd2Nb2O7

    PRECISE SEMI-AUTOMATIC FIELD MAPPING IN THE SPLIT FIELD MAGNET OF THE ISR

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    Abstract The computer-controlled equipment for the magnetic measurements of the Split Field Magnet System of the CERN Intersecting Storage Rings is described. Three different measurement machines are necessary for the measurements of this large and complex magnet system. The strongly inhomogeneous field is measured to a precision of 1 0/00 of maximum field using Hall-plate assemblies. The final data treatment includes the smoothing out of the established scalar potential by solving the Laplace's equation from the conditions at the boundaries by means of relaxation. The threedimensional field map will be used for particle analysis. Effects of the SFM-field on the circulating ISR beams are evaluated and optimized

    The Reintegration of Ex-Combatants and Post-Conflict Violence. An Analysis of Municipal Crime Levels in Colombia

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    Violent crime in Colombia is analyzed following the demobilization of ex-combatants using municipal-level data. The main findings are that an increased presence of ex-combatants does not systematically increase homicides, but may increase robberies. Reintegration programs are shown to matter. Former paramilitaries who are not in a reintegration program increase crime. Former guerillas increase robberies, regardless of whether they are in or out of reintegration, but homicides decrease for guerrillas in reintegration. Ex-combatants often settle in municipalities with more crime. Controlling for reverse causality, ex-combatants only increase crime if they are not in reintegration, while in reintegration they may reduce crime

    THE LHC POST MORTEM ANALYSIS FRAMEWORK

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    Abstract The LHC with its unprecedented complexity and criticality of beam operation will need thorough analysis of data taken from systems such as power converters, interlocks and beam instrumentation during events like magnet quenches and beam loss. The causes of beam aborts or in the worst case equipment damage have to be revealed to improve operational procedures and protection systems. The correct functioning of the protection systems with their required redundancy has to be verified after each such event. Post mortem analysis software for the control room has been prepared with automated analysis packages in view of the large number of systems and data volume. This paper recalls the requirements for the LHC Beam Post Mortem System (PM) and the necessity for highly reliable data collection. It describes in detail the redundant architecture for data collection as well as the chosen implementation of a multi-level analysis framework, allowing for automated analysis and qualification of a beam dump event based on expert provided analysis modules. It concludes with an example of the data taken during first beam tests in September 2008 with a first version of the system
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