1,609 research outputs found

    Thermal entanglement and efficiency of the quantum Otto cycle for the su(1,1) Tavis-Cummings system

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    The influence of the dynamical Stark shift on the thermal entanglement and the efficiency of the quantum Otto cycle is studied for the su(1,1) Tavis-Cummings system. It is shown that the degree of the thermal entanglement becomes larger as the dynamical Stark shift increases. In contrast, the efficiency of the Otto cycle is degraded with an increase of the values of dynamical Stark shift. Expressions for the efficiency coefficient are derived. Using those expressions we identify the maximal efficiency of the quantum Otto cycle from the experimentally measured values of the dynamical Stark shiftComment: to appear in J.Phys.

    Synthesis and characterization of TiO2 nanotubes as anodic material in lithium-ion batteries

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    The aim of this work is to analyze the efficiency of titania nanotubes acting as anode for lithium-ion batteries. The titania nanotubes has been obtained using an anodization process in a ethylene glycol solution, containing ammonium fluoride and a small quantity of water. After a heat treatment, needed to crystallize the material in the anatase form, the nanotubes has been analyzed in their performance as anode in a Li-ion battery. Structural and morphologic characterization of the titania nanotubes have been studied using XRD and SEM analysis, while the galvanostatic cycles has been collected in order to examine the electrochemical performance as electrodic material. Finally, a comparison of the electrochemical performance between our samples and commercial nanostructured titanium oxide, has been made, obtaining that the TiO2 nanotube electrodes treatmen reduces the overall cell voltage and provides good retention capacity on cycling and higher capacity at all used C-rate

    QUALITE DES MODELES NUMERIQUES DE TERRAIN DERVIES PAR CORRELATION AUTOMATIQUE

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    Digital Terrain Models are plying an important role as information layer, mainly with the development of geographic information systems, since they describe the topographic surface of the terrain and hence it constitutes a valuable support for the study of variety of geographical and environmental events. With the advent of digital techniques and the advantages they are offering in terms of automation and precision, users are adopting image matching techniques to derive automatically Digital Terrain Models. The quality of these DTM are determined by different factors (photo scale, scanning resolution and software parameterization). This paper is a contribution to evaluate the influence of some of some factors on the final accuracy of DTM derived by correlation. In this respect, different tests were carried out on two photo scales (1/7500 an 1/20000) flown on varying topography. The photos were scanned to 20, 25, 32 and 42 microns pixel sizes and digital terrain models were derived using ViruoZo software from Supresoft. The assessment of the derived DTMs quality was based on qualitative (visual comparisons of contours) and quantitative ( RMS computed from residuals on ground check points) criteria. Results showed that, in rugged terrain, DTM derived from 1/20000 photos are accurate to 32cm, which may enable deriving contours with 1 m interval. The introduction of break lines prior to the correlation seems to have less influence on the accuracy of derived DTM when the generated grid is very dense, but contributes to reduce the editing burden. The high accuracy of automatically derived DTM may contribute to make less tight the map to photo scale ratio. For instance mapping at 1/5000 from 1/20000 photos can preserve the height accuracy, while with conventional methods, height accuracy at 1/5000 map scale is preserved usually for mapping from 1/12000. 1

    An Assessment Instrument of Technological Literacies in Makerspaces and FabLabs

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    Background As the maker movement is increasingly adopted into K‐12 schools, students are developing new competences in exploration and fabrication technologies. This study assesses learning with these technologies in K‐12 makerspaces and FabLabs. Purpose Our study describes the iterative process of developing an assessment instrument for this new technological literacy, the Exploration and Fabrication Technologies Instrument, and presents findings from implementations at five schools in three countries. Our index is generalizable and psychometrically sound, and permits comparison between student confidence and performance. Design/Method Our evaluation of distinct technology skills separates general computing, information and communication technology (ICT), and exploration and fabrication technologies (EFTs) into nonoverlapping areas of technological expertise required to perform their respective sets of tasks. The instrument also tracks student confidence in EFT skills and assesses how that confidence relates to actual task performance. Results Exploration and fabrication technologies constitute a new and distinct set of technology literacies arising from fabrication settings. The EFT instrument compares students\u27 self‐reported confidence with their performance on complex design tasks and demonstrates that, for students, exposure to general computing and ICT tools differs from exposure to EFT tools. Conclusion The EFT instrument captures a new and distinct set of technology literacies that arise within fabrication settings and are independent of both general computing and digital content production skills

    Emotional Dissonance and the Information Technology Professional: A Methodological Replication Study

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    This study is a methodological replication of Emotional Dissonance and the Information Technology Professional by Rutner, Hardgrave, and McKnight (2008). Though we adopted the original study\u27s hypotheses and research methodology, we add to that research by investigating generational differences, increasing the sample size, and including respondents from multiple firms and industries. In this replication, we were able to 1) establish continued support for the direct impact of emotional dissonance on work exhaustion, 2) increase the explanatory power, and 3) provide broader generalizability through sampling subjects from multiple firms. We discuss both the practical and theoretical implications of these findings

    Innovative nanomaterials for fuel cells fed with biogas

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    Challenges on sustainability promote research policy focused on renewable-energy technology development in order to enhance global energy security, local energy independence, environmental protection and economic growth. Biomass resources offer renewable energies that can play a key role in the current global strategies for reducing greenhouse gas emissions by partially replacing fossil fuels. The conversion of biomass chemical energy into electrical energy and cogenerated heat can be obtained by fuel cells. In particular, molten carbonate fuel cell (MCFC) is the most suitable device for bioenergy production because it can be fed directly with biogas, whose primary constituents all improve the performance of the cell. However hydrogen sulfide, which is the main biogas impurity, poisons the traditional nickel based anode, affecting the power and the endurance of the cell. In order to overcome this problem, an innovative anode material that resists against the sulfide corrosions has been developed. This material, made of a nanostructured and porous nickel support covered with a thin layer of ceria, exhibits high sulfur tolerance and recovering capability

    Innovative nanomaterials for fuel cells fed with biogas

    Get PDF
    Challenges on sustainability promote research policy focused on renewable-energy technology development in order to enhance global energy security, local energy independence, environmental protection and economic growth. Biomass resources offer renewable energies that can play a key role in the current global strategies for reducing greenhouse gas emissions by partially replacing fossil fuels. The conversion of biomass chemical energy into electrical energy and cogenerated heat can be obtained by fuel cells. In particular, molten carbonate fuel cell (MCFC) is the most suitable device for bioenergy production because it can be fed directly with biogas, whose primary constituents all improve the performance of the cell. However hydrogen sulfide, which is the main biogas impurity, poisons the traditional nickel based anode, affecting the power and the endurance of the cell. In order to overcome this problem, an innovative anode material that resists against the sulfide corrosions has been developed. This material, made of a nanostructured and porous nickel support covered with a thin layer of ceria, exhibits high sulfur tolerance and recovering capability

    Mental Health and Information Technology Catalysts as Determinants of Innovative Work Behavior

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    Interpersonal interactions, such as impromptu face-to-face workplace conversations, facilitate knowledge transfer and spur innovation within individual work roles; however, the move to remote work during the COVID-19 pandemic disrupted these dynamics. This research examines how innovation can be maintained in remote work settings by considering Information Technology (IT) catalysts (a combination of IT mindfulness, IT identity, and IT empowerment) during disruptive events and crises. We also highlight the importance of remote workers’ mental health and coping as precursors for IT catalysts to stimulate innovative work behaviors. Our paper contributes to information systems (IS) theory by establishing remote workers’ mental health and coping as distal factors of innovation and precursors to IT catalysts. In addition, we extend IS theory by establishing the relationships among the IT catalyst factors as well as their impact on innovative work behaviors. Our research provides insights for organizations interested in sustaining innovation, especially during crises or other stress-inducing events or conditions
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