45 research outputs found

    Prototype Design and Feasibility Analysis for Self-Levitated Conveying

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    In order to avoid friction and scratching when conveying object, an acoustic levitation prototype was designed to verify the feasibility. The modal shapes and the forced harmonic shapes of the prototype are obtained by an ANSYS coupled field computation with a one-quarter symmetry model and the levitation capacity was assessed by the use of groups of simulation and physical testing. The simulation results showed that the pure flexural and mixed flexural wave shapes with different wave numbers existed at some specific frequency. The amplitude in the central point of an aluminum plate having four piezo-electric discs glued to the bottom surface was simulated for a frequency spectrum. The experimental results confirmed the theoretical results and the feasibility of the prototype and confirm that objects can be floated at several resonant frequencies under forced vibrating condition. The system can provide largest bearing capacity when both the piezoelectric disc and the plate resonances coincide

    Fine-tuning of the confined space in microporous metal–organic frameworks for efficient mercury removal

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    Offsetting the impact of human activities on the biogeochemical cycle of mercury has become necessary for a sustainable planet. Herein, we report the development of a water-stable and eco-friendly metal–organic framework, which has the formula {Cu4II[(S,S)-methox]2}·5H2O (1), where methox is bis[(S)-methionine]oxalyl diamide. Its features include narrow functional channels decorated with thioalkyl chains, which are able to capture HgCl2 from aqueous media in an efficient, selective, and rapid manner. The conscious design effort in terms of size, shape, and reactivity of the channels results in extremely efficient immobilization of HgCl2 guest species in a very stable conformation, similar to that of the enzyme mercury reductase. Thus, 1 enables the highly efficient removal of toxic HgCl2 from aqueous media and reduces the [Hg2+] concentration from the dangerous level of 10 ppm to acceptable limits of below 2 ppb in drinking water. The unusual combination of a low-cost straightforward synthetic procedure and high stability under environmental conditions, together with its ability to efficiently and rapidly remove poisonous mercury ions, places 1 among the most attractive adsorbents reported to date for the purification of contaminated water.This work was supported by the MINECO (Spain) (Project CTQ2016-75671-P and Excellence Unit “Maria de Maeztu” MDM-2015-0538), the Generalitat Valenciana (Spain) (Project PROMETEOII/2014/070), and the Ministero dell'Istruzione, dell'UniversitĂ  e della Ricerca (Italy). M. M. and X. Q. thank the MINECO and the China Scholarship Council for grants. Thanks are also extended to the RamĂłn y Cajal program (E. P and E. V. R.-F.)

    Parallel Expansions of Sox Transcription Factor Group B Predating the Diversifications of the Arthropods and Jawed Vertebrates

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    Group B of the Sox transcription factor family is crucial in embryo development in the insects and vertebrates. Sox group B, unlike the other Sox groups, has an unusually enlarged functional repertoire in insects, but the timing and mechanism of the expansion of this group were unclear. We collected and analyzed data for Sox group B from 36 species of 12 phyla representing the major metazoan clades, with an emphasis on arthropods, to reconstruct the evolutionary history of SoxB in bilaterians and to date the expansion of Sox group B in insects. We found that the genome of the bilaterian last common ancestor probably contained one SoxB1 and one SoxB2 gene only and that tandem duplications of SoxB2 occurred before the arthropod diversification but after the arthropod-nematode divergence, resulting in the basal repertoire of Sox group B in diverse arthropod lineages. The arthropod Sox group B repertoire expanded differently from the vertebrate repertoire, which resulted from genome duplications. The parallel increases in the Sox group B repertoires of the arthropods and vertebrates are consistent with the parallel increases in the complexity and diversification of these two important organismal groups

    Exploring the potential effects of emoticons

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    Instant messaging (IM) has shown signs of becoming one of the main stream communication applications for users, like e-mail. Many people maintain constant contacts with multiple friends and relations via IM simultaneously whenever they are online, whether working on other applications or not. In addition to allowing instant exchange of text information, a unique feature of IM is its use of graphical icons that express emotions, known as emotional icons or emoticons. We explored their potential effects. Our model, based on prior theory and research, was tested using data collected from student users; it was analyzed to reveal potential effects of emoticons on various factors related to the use of IM. Our study used structural equation modeling (SEM) analysis; the results showed that the user of emoticons felt a positive effect on enjoyment, personal interaction, perceived information richness, and perceived usefulness. Our results suggested, however, that emoticons were not just enjoyable to use, but also a valuable addition to communication methods. © 2008 Elsevier B.V. All rights reserved

    What do consumers really know about spyware?

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    Epoxidation vs. dehydrogenation of allylic alcohols: heterogenization of the VO(acac)2 catalyst in a metal–organic framework

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    Allylic alcohol epoxidation and dehydrogenation reactivity is distinguished when VO(acac)2 is used in solution or anchored in a metal–organic framework (MOF). The chemical mechanism depends on the electronic profile of alkene substituents when the vanadyl complex is used in the homogenous phase. However, confinement effects imparted by MOF channels allow gaining control of the chemoselectivity toward the dehydrogenation product.Peer reviewe
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