428 research outputs found

    Nondestructive evaluation techniques for nickel-cadmium aerospace battery cells

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    The ac impedance characteristics of Ni-Cd cells as an in-situ, nondestructive means of determining cell lifetime, particularly with respect to the probability of premature failure were evaluated. Emphasis was on evaluating Ni-Cd cell impedance over a wide frequency range (10,000 to 0.0004 Hz) as the cells were subjected to charge/discharge cycle testing. The results indicate that cell degradation is reflected in the low frequency (Warburg) impedance characteristics associated with diffusion processes. The Warburg slope (W) was found to steadily increase as a function of cell aging for completely discharged cells. In addition, based on data for two cells, a high or rapidly increasing value for W signals imminent cell failure by one mechanism. Degradation by another mechanism is apparently reflected in a fall-off (roll-over) of W at lower frequencies. As a secondary result, the frequency dependence of the absolute cell impedance at low frequencies (5 - 500 mHz) was found to be a good indication of the cell state-of-charge

    Experimental constraints on a dark matter origin for the DAMA annual modulation effect

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    A claim for evidence of dark matter interactions in the DAMA experiment has been recently reinforced. We employ a new type of germanium detector to conclusively rule out a standard isothermal galactic halo of Weakly Interacting Massive Particles (WIMPs) as the explanation for the annual modulation effect leading to the claim. Bounds are similarly imposed on a suggestion that dark pseudoscalars mightlead to the effect. We describe the sensitivity to light dark matter particles achievable with our device, in particular to Next-to-Minimal Supersymmetric Model candidates.Comment: v4: introduces recent results from arXiv:0807.3279 and arXiv:0807.2926. Sensitivity to pseudoscalars is revised in light of the first. Discussion on the subject adde

    Results from a Search for Light-Mass Dark Matter with a P-type Point Contact Germanium Detector

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    We report on several features present in the energy spectrum from an ultra low-noise germanium detector operated at 2,100 m.w.e. By implementing a new technique able to reject surface events, a number of cosmogenic peaks can be observed for the first time. We discuss several possible causes for an irreducible excess of bulk-like events below 3 keVee, including a dark matter candidate common to the DAMA/LIBRA annual modulation effect, the hint of a signal in CDMS, and phenomenological predictions. Improved constraints are placed on a cosmological origin for the DAMA/LIBRA effect.Comment: 4 pages, 4 figures. v2: submitted version. Minimal changes in wording, one reference adde

    Sceptical Employees as CSR Ambassadors in Times of Financial Uncertainty

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    This chapter offers new insights into the understanding of internal (employee) perceptions of organizational corporate social responsibility (CSR) policies and strategies. This study explores the significance of employees’ involvement and scepticism upon CSR initiatives and focuses on the effects it may have upon word of mouth (WOM) and the development of employee–organisation relationships. Desk research introduces the research questions. Data for the research questions were gathered through a self-completion questionnaire distributed in a hardcopy form to the sample. An individual’s level of scepticism and involvement appears to affect the development of a positive effect on employees’ WOM. Involvement with the domain of the investment may be a central factor affecting relationship building within the organization, and upon generation of positive WOM. The chapter offers a conceptual framework to public relations (PR) and corporate communications practitioners, which may enrich their views and understanding of the use and value of CSR for communication strategies and practices. For-profit organisations are major institutions in today’s society. CSR is proffered as presenting advantages for (at macro level) society and (micro level) the organization and its employees. Concepts, such as involvement and scepticism, which have not been rigorously examined in PR and corporate communication literature, are addressed. By examining employee perceptions, managers and academic researchers gain insights into the acceptance, appreciation and effectiveness of CSR policies and activities upon the employee stakeholder group. This will affect current and future CSR communication strategies. The knowledge acquired from this chapter may be transferable outside the for-profit sector

    Quantum Optics and Photonics

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    Contains reports on seven research projects.U.S. Air Force Geophysics Laboratory (Contract F19628-70-C-0082)Joint Services Electronics Program (Contract DAAG29-83-K-0003)National Science Foundation (Grant PHY82-10369)U.S. Air Force - Rome Air Development Center (in collaboration with C.C. Leiby, Jr.)U.S. Air Force - Rome Air Development Center (Contract F19628-80-C-0077)U.S. Air Force - Office of Scientific Research (Contract F49620-82-C-0091

    Large-Mass Ultra-Low Noise Germanium Detectors: Performance and Applications in Neutrino and Astroparticle Physics

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    A new type of radiation detector, a p-type modified electrode germanium diode, is presented. The prototype displays, for the first time, a combination of features (mass, energy threshold and background expectation) required for a measurement of coherent neutrino-nucleus scattering in a nuclear reactor experiment. The device hybridizes the mass and energy resolution of a conventional HPGe coaxial gamma spectrometer with the low electronic noise and threshold of a small x-ray semiconductor detector, also displaying an intrinsic ability to distinguish multiple from single-site particle interactions. The present performance of the prototype and possible further improvements are discussed, as well as other applications for this new type of device in neutrino and astroparticle physics (double-beta decay, neutrino magnetic moment and WIMP searches).Comment: submitted to Phys. Rev.

    Photonics

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    Contains reports on seven research projects.Air Force Rome Air Development Center (in collaboration with C.C. Leiby, Jr.)U.S. Air Force-Rome Air Development Center (Contract F19628-80-C-0077)National Science Foundation (Grant PHY79-09739)Joint Services Electronics Program (Contract DAAG29-80-C-0104)U.S. Air Force Geophysics Laboratory (Contract F19628-79-C-0082

    Reconceptualizing CSR in the media industry as relational accountability

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    In this paper, we reconceptualize CSR in the media industries by combining empirical data with theoretical perspectives emerging from the communication studies and business ethics literature. We develop a new conception of what corporate responsibility in media organizations may mean in real terms by bringing Bardoel and d’Haenens’ (European Journal of Communication 19 165–194 2004) discussion of the different dimensions of media accountability into conversation with the empirical results from three international focus group studies, conducted in France, the USA and South Africa. To enable a critical perspective on our findings, we perform a philosophical analysis of its implications for professional, public, market, and political accountability in the media, drawing on the insights of Paul Virilio. We come to the conclusion that though some serious challenges to media accountability exist, the battle for responsible media industries is not lost. In fact, the speed characterizing the contemporary media environment may hold some promise for fostering the kind of relational accountability that could underpin a new understanding of CSR in the media

    Performance of the DNA-citoliq liquid-based cytology system compared with conventional smears

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    To evaluate the performance of a new, manual, simplified liquid-based system, DNA-Citoliq (Digene Brasil), employed under routine conditions as compared to conventional smears collected from six collaborating private laboratories. Methods: A panel of cytopathologists, who served as the gold standard diagnosis, adjudicated discordant opinions. Results: Of 3206 pairs of slides considered valid for comparison, there were 3008 in full agreement (93.8%), 112 (3.5%) with one diagnostic category discrepancies, and 86 (2.7%) discordant cases. Among the 288 borderline+ by either method, DNA-Citoliq detected abnormalities in 243 (84.4%), and conventional smears (CS) detected abnormalities in 178 (61.8%) (McNemar test, P < 0.000), a 36.5% increased detection of borderline+ cases. Conclusions: For mild dyskaryosis, DNA-Citoliq detected 176 cases and CS 125 cases (McNemar test, P < 0.000); and for moderate+severe dyskaryosis 66 versus 32 cases respectively (McNemar test, P < 0.000)
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