Search results for " support"
showing 10 items of 1591 documents
Thermal stability, structural properties and catalytic activity of Pd catalysts supported on Al2O3–CeO2–BaO mixed oxides prepared by sol–gel method
2003
Abstract Al2O3–CeO2–BaO oxides with constant Al/Ba mass ratio and increasing cerium content were prepared, using the sol–gel procedure, and calcined at 1000 °C for 5 h. The influence of barium oxide on the thermal stability and on the morphological and structural properties of the corresponding supports, in terms of increasing surface area of alumina and ceria dispersion, was studied. The corresponding Pd (1 wt.%) catalysts were prepared by a stepwise impregnation method with a solution of palladium acetylacetonate in benzene. Palladium was introduced in two sequential steps by impregnation 0.5 wt.% of Pd each time. The structural and textural properties of the materials were studied by X-r…
A Cross-Regional Exploration of Barriers to the Adoption and Use of Electronic Meeting Systems
2007
Originally published in the journal Group Decision and Negotiation: http://www.springerlink.com/content/100270/ Electronic Meeting Systems (EMS) are intended to support group collaboration in completing tasks. While there have been many case studies and laboratory experiments on how EMS can support group tasks, large scale macro investigations exploring EMS adoption and use have been practically non-existent. Furthermore, while several barriers to EMS adoption and use have been suggested, their validation across organizations remains unexplored. We undertook a global initiative to explore information technology support for task-oriented collaboration in the US, Australia, Hong Kong, and Nor…
Apoyo a la autonomía, satisfacción de las necesidades psicológicas y bienestar : invarianza de un modelo estructural en futbolistas y bailarines
2015
La teoría de las necesidades psicológicas básicas (Deci y Ryan, 2000) defiende que en los contextos sociales en los que se apoya la autonomía se promueve el bienestar a través de la satisfacción de las necesidades psicológicas básicas. En base a este marco teórico, el objetivo del presente trabajo fue triple: primero, poner a prueba un modelo en el que se analizaba la secuencia: percepción del apoyo a la autonomía ofrecido por el profesor/entrenador - satisfacción de las necesidades psicológicas básicas - bienestar; segundo, examinar el papel mediador de las necesidades, y tercero, estudiar la invarianza del modelo entre dos poblaciones. Participaron 197 bailarines (Medad = 18,65 ± 3,73) y …
Experimental observations of upstream overdeepening
2005
The issue of morphodynamic influence in meandering streams is investigated through a series of laboratory experiments on curved and straight flumes. Both qualitative and quantitative observations confirm the suitability of the recent theoretical developments (Zolezzi & Seminara 2001) that indicate the occurrence of two distinct regimes of morphodynamic influence, depending on the value of the width ratio of the channel β. The threshold value βR separating the upstream from the downstream influence regimes coincides with the resonant value discovered by Blondeaux & Seminara (1985). Indeed it is observed that upstream influence may occur only in relatively wide channels, while narrower stream…
Design of an innovative system for precision beekeeping
2019
The innovative technologies of precision agriculture can be applied today to different productive sectors of agriculture in order to optimize crop production and to improve the quality of the final products. One of these is beekeeping, a very important sector both from an environmental and a production standpoint. The production of honey depends on many factors, some of which are environmental factors such as temperature, relative humidity and wind. The aim of this study was the design of a Precision Apicolture System (PAS) platform for monitoring and controlling the main environmental factors, both inside and outside the hive, in order to assess their influence on the honey daily productio…
Social network and addiction.
2009
In recent decades, the rapid development of innovative Internet-based communication technologies created a new field of academic study among scholars. Particularly, the attention of researchers is focusing on new ways to form relationship-thought social web. Social Network sites constitute a new form of web communities, where people meet and share interests and activities. Due to exponential growth of these sites, an increasing number of scholars are beginning to study the emergent phenomena in order to identify any psychopathological risk related to use of social web, such as addiction. This article examines the recent literature about this issue. In recent decades, the rapid development o…
Catalytic transesterification of Pistacia chinensis seed oil using HPW immobilized on magnetic composite graphene oxide/cellulose microspheres
2018
Abstract In the present study, magnetic composite graphene oxide/cellulose (GO/CM@Fe3O4) microspheres were prepared as support material, which are cost-efficient, non-toxic and environmental friendly. The microspheres with higher adsorption capacity were further modified using triethylene tetramine (TETA), and H3PW12O40 (HPW) was immobilized to form GO/CM-NH2@Fe3O4-HPW microspheres as heterogeneous catalyst for biodiesel production. The novel heterogeneous catalyst was characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), Brunauer-Emmett-Teller (BET) and X-ray diffractometry (XRD). For the first time, GO/CM-NH2@Fe3O4--HPW was applied in the tr…
EVpedia: a community web portal for extracellular vesicles research
2014
Abstract Motivation: Extracellular vesicles (EVs) are spherical bilayered proteolipids, harboring various bioactive molecules. Due to the complexity of the vesicular nomenclatures and components, online searches for EV-related publications and vesicular components are currently challenging. Results: We present an improved version of EVpedia, a public database for EVs research. This community web portal contains a database of publications and vesicular components, identification of orthologous vesicular components, bioinformatic tools and a personalized function. EVpedia includes 6879 publications, 172 080 vesicular components from 263 high-throughput datasets, and has been accessed more tha…
Predatory journals enter biomedical databases through public funding
2020
Predatory publishing is an international, cross disciplinary threat to the integrity of the scientific system • A worrying number of articles published in predatory journals are indexed in biomedical databases such as PubMed, the free access biomedical database maintained by the National Library of Medicine • Public funding, under open access policies, seems to be the mechanism by which articles are displayed in PubMed. • Providing guidance to publicly funded authors on how to publish their work in legitimate open-access venues will likely stop the wasteful use of public money to cover the fees of predatory journals.
Processing of rock core microtomography images: Using seven different machine learning algorithms
2016
The abilities of machine learning algorithms to process X-ray microtomographic rock images were determined. The study focused on the use of unsupervised, supervised, and ensemble clustering techniques, to segment X-ray computer microtomography rock images and to estimate the pore spaces and pore size diameters in the rocks. The unsupervised k-means technique gave the fastest processing time and the supervised least squares support vector machine technique gave the slowest processing time. Multiphase assemblages of solid phases (minerals and finely grained minerals) and the pore phase were found on visual inspection of the images. In general, the accuracy in terms of porosity values and pore…