1,721,004 research outputs found
Atomic-Layer-Deposited MoNx Thin Films on Three-Dimensional Ni Foam as Efficient Catalysts for the Electrochemical Hydrogen Evolution Reaction
No full textFuture realization of a hydrogen-based economy requires a high-surface-area, low-cost, and robust electrocatalyst for the hydrogen evolution reaction (HER). In this study, the MoNx thin layer is synthesized on to a high-surface area three-dimensional (3D) nickel foam (NF) substrate using atomic layer deposition (ALD) for HER catalysis. MoNx is grown on NF by the sequential exposure of Mo(CO)(6) and NH3 at 225 degrees C. The thickness of the thin film is controlled by varying the number of ALD cycles to maximize the HER performance of the MoNx/NF composite catalyst. The scanning electron microscopy and transmission electron microscopy (TEM) images of MoNx/NF highlight that ALD facilitates uniform and conformal coating. TEM analysis highlights that the MoNx film is predominantly amorphous with the nanocrystalline MoN grains (4 nm) dispersed throughout it. Moreover, the high-resolution (HR)-TEM analysis shows a rough surface of the MoNx film with an overall composition of Mo0.59N0.41. X-ray photoelectron spectroscopy depth-profile analysis reveals that oxygen contamination is concentrated at the surface because of surface oxidation of the MoN film under ambient conditions. The HER activity of MoNx is evaluated under acidic (0.5 M H2SO4) and alkaline (0.1 M KOH) conditions. In an acidic electrolyte, the sample prepared with 700 ALD cycles exhibits significant HER activity and a low overpotential (eta) of 148 mV at 10 mA cm(-2). Under an alkaline condition, it achieves 10 mA cm(-2) with eta of 125 mV for MoNx/NF (700 cycles). In both electrolytes, the MoNx thin film exhibits enhanced activity and stability because of the uniform and conformal coating on NF. Thus, this study facilitates the development of a large-area 3D freestanding catalyst for efficient electrochemical water-splitting, which may have commercial applicability
Enhanced activity of highly conformal and layered tin sulfide (SnSx) prepared by atomic layer deposition (ALD) on 3D metal scaffold towards high performance supercapacitor electrode
Full text linkLayered Sn-based chalcogenides and heterostructures are widely used in batteries and photocatalysis, but its utilizations in a supercapacitor is limited by its structural instability and low conductivity. Here, SnSx thin films are directly and conformally deposited on a three-dimensional (3D) Ni-foam (NF) substrate by atomic layer deposition (ALD), using tetrakis(dimethylamino) tin [TDMASn, ((CH3)(2)N)(4)Sn] and H2S that serves as an electrode for supercapacitor without any additional treatment. Two kinds of ALD-SnSx films grown at 160 degrees C and 180 degrees C are investigated systematically by X-ray diffractometry, Raman spectroscopy, X-ray photoelectron spectroscopy, and transmission electron microscopy (TEM). All of the characterization results indicate that the films deposited at 160 degrees C and 180 degrees C predominantly consist of hexagonal structured-SnS2 and orthorhombic-SnS phases, respectively. Moreover, the highresolution TEM analyses (HRTEM) reveals the (001) oriented polycrystalline hexagonal-SnS2 layered structure for the films grown at 160 degrees C. The double layer capacitance with the composite electrode of SnSx@ NF grown at 160 degrees C is higher than that of SnSx@ NF at 180 degrees C, while pseudocapacitive Faradaic reactions are evident for both SnSx@ NF electrodes. The superior performance as an electrode is directly linked to the layered structure of SnS2. Further, the optimal thickness of ALD-SnSx thin film is found to be 60 nm for the composite electrode of SnSx@ NF grown at 160 degrees C by controlling the number of ALD cycles. The optimized SnSx@ NF electrode delivers an areal capacitance of 805.5 mF/cm(2) at a current density of 0.5 mA/cm(2) and excellent cyclic stability over 5000 charge/discharge cycles.TRU
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Effect of Asymmetric Foot Placement and Reduced Weight-Bearing Asymmetry on the Sit-to-Stand Task of a Unilateral Transfemoral Amputee
No full textThe Sit-to-Stand (SiSt) task is one of the most crucial yet mechanically demanding daily tasks. A transfemoral amputee develops high torques on the intact leg to complete the SiSt task. Such high torques are a consequence of limited torques produced by a prosthesis. The main interest of this project is on the sit-to-stand task of a transfemoral amputee fitted with an active knee and passive ankle prosthesis. The objective is to test whether strategies like asymmetric foot placement and reduced weight-bearing asymmetry could reduce the torque produced in the intact knee. Musculoskeletal model of an able-bodied human subject and a transfemoral amputee subject enabled with an active knee prosthesis is developed. Forward dynamic optimisations are performed by defining an appropriate framework required for simulating the sit-to-stand task. The process was verified by implementing the framework on the musculoskeletal model of an able-bodied individual and comparing it with experimental results available in the literature. The comparison showed a good agreement of simulated results with results reported in the literature. Joint torque profiles of the intact limb of the amputee model were then simulated with asymmetric foot placement and reduced weight-bearing asymmetry strategies. Placing the prosthetic leg posterior to the intact leg reduced the peak intact knee torques by 1.5% relative to placing the intact leg adjacent to the prosthetic leg. The peak intact knee joint torques were reduced by 13% in SiSt task simulation with reduced weight-bearing asymmetry. An increased metabolic cost needed to perform the SiSt task also resulted from this strategy.Mechanical Engineering | BioMechanical Desig
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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