Search results for "composition"
showing 10 items of 2675 documents
Evolution of the optimal catalytic systems for the oxidative dehydrogenation of ethane: The role of adsorption in the catalytic performance
2022
Three samples that correspond to the evolution of optimal catalytic systems for the oxidative dehydrogenation of ethane have been synthesized and compared in terms of catalytic behavior and adsorption properties: (i) vanadium oxide supported on alumina, (ii) Sn-promoted NiO, and (iii) multicomponent MoVTeNbO with the M1 structure. The main difference in catalytic performance lies in the extent of the overoxidation of the ethylene formed, following the order VOx/Al2O3 > NiSnOx > MoVTeNb-M1. Accordingly, the selectivity to ethylene at medium and high ethane conversion follows the order MoVTeNb-M1 > NiSnOx > VOx/Al2O3. These results are confirmed by the relative reaction rates observed for the…
Determinants of Board Size, Composition and Leadership
2018
Using a 14-year panel data set on the Standard and Poor’s 1500 firms, this chapter examines the trends and determinants of corporate board structure (Board size, independence and CEO duality). Our hypotheses lead to predictions that firm complexity and advising requirements, the costs of monitoring and advising, ownership structure and CEO characteristics are important determinants of board structure. Our findings provide strong empirical evidence in support of these hypotheses. We also find some evidence that the Sarbanes–Oxley Act has had an impact on board structure and its determinants.
Impact of body weight, low energy diet and gastric bypass on drug bioavailability, cardiovascular risk factors and metabolic biomarkers: protocol for…
2018
IntroductionRoux-en-Y gastric bypass (GBP) is associated with changes in cardiometabolic risk factors and bioavailability of drugs, but whether these changes are induced by calorie restriction, the weight loss or surgery per se, remains uncertain. The COCKTAIL study was designed to disentangle the short-term (6 weeks) metabolic and pharmacokinetic effects of GBP and a very low energy diet (VLED) by inducing a similar weight loss in the two groups.Methods and analysisThis open, non-randomised, three-armed, single-centre study is performed at a tertiary care centre in Norway. It aims to compare the short-term (6 weeks) and long-term (2 years) effects of GBP and VLED on, first, bioavailability…
Towards Technology for Supporting Effective Online Learning Groups
2018
Group learning has been advocated for increasing active learning among distance learners. However, there is limited understanding on how to engage learners in online courses. Following the design science methodology, we iteratively developed guiding factors for supporting effective online learning groups. The factors for effective online learning groups cover five key dimensions, namely institutional policies, institutional technology, group activity, group composition, and facilitation. The factors are validated through repetitive evaluation using authentic online learning courses, as well as using a focus group discussion with experienced online facilitators. This way, the factors provide…
Metaontology
2015
[ES] El término «metaontología» se aplica a la indagación sobre la naturaleza de la ontología. Si bien este tipo de indagación tiene importantes precedentes en la historia de la filosofía moderna, en los últimos quince años ha cobrado renovado interés dentro de la tradición analítica, en parte debido al notorio desarrollo de la ontología misma en las últimas décadas. En este capítulo se presentarán algunos de los principales problemas metaontológicos, y las posiciones más destacadas sobre los mismos. [EN] The term «metaontology» applies to the inquiry on the nature of ontology. Although this type of inquiry has important precedents in the history of modern philosophy, in the last fifteen ye…
The Open Innovation in Science research field: a collaborative conceptualisation approach
2020
Openness and collaboration in scientific research are attracting increasing attention from scholars and practitioners alike. However, a common understanding of these phenomena is hindered by disciplinary boundaries and disconnected research streams. We link dispersed knowledge on Open Innovation, Open Science, and related concepts such as Responsible Research and Innovation by proposing a unifying Open Innovation in Science (OIS) Research Framework. This framework captures the antecedents, contingencies, and consequences of open and collaborative practices along the entire process of generating and disseminating scientific insights and translating them into innovation. Moreover, it elucidat…
Programmable opticaldigital processor for rank order and morphological filtering
1995
A flexible hybrid opto-electronic processor for rank-order and morphological filtering is presented. The system is based on the shadow-casting convolver architecture, and the threshold decomposition concept. It provides the possibility of programming the input image and structuring element at video rate. The possibilities of the processor are experimentally demonstrated.
A gradient-based decomposition approach to optimize pressure path and counterpunch action in Y-shaped tube hydroforming operations
2008
International audience; In tube hydroforming, the concurrent actions of pressurized fluid and mechanical feeding allows obtaining tube shapes characterized by complex geometries such as different diameters sections and/or bulged zones. Main process parameters are material feeding history (i.e., the punches velocity history), internal pressure path during the process, and (in T- or Y-shaped tube hydroforming) counterpunch action. What is crucial, in such processes, is the proper design of operative parameters aimed to avoid defects (for instance underfilling or ductile fractures). Actually, the design of tube hydroforming operations is mainly aimed to prevent bursting or buckling occurrence …
Erosive effect of industrialized fruit juices exposure in enamel and dentine substrates: An in vitro study
2021
Background Erosive tooth wear has been a highly prevalent and emerging phenomenon related to eating habits of the population. Aim: This study sought to investigate industrialized fruit juices exposure in enamel and dentine substrates in terms of erosive effect. Material and methods Human enamel and dentine specimens were randomized into 8 groups (n=8): Grape juice - Ades®, Grape juice - Del Valle Kapo®, Grape juice - Aurora®, Orange juice - Del Valle Kapo®, Orange juice - Ades®, Strawberry juice - Mais Vita®, Strawberry juice - Ades®, Citrus fruit juice - Tampico®. Specimens were submitted to an in vitro erosive challenge and to a microhardness test to evaluate the percentage of surface mic…
Der austausch des cyclopentadienylliganden im methylcyclopentadienyl-mangantricarbonyl
1981
Abstract The exchange of the cyclopentadienyl ring in methylcyclopentadienylmanganese(I) tricarbonyl by methy-substituted benzenes in the presence of aluminium halide leads to [arene-Mn(CO) 3 ] + -ions. The reaction conditions have been optimised; in addition to the yield the purity of the complexes has been determined in some detail. After mild decomposition the arenes were analysed by GLC. Pure [arene-Mn(CO) 3 ] + -ions can be isolated with benzene, toluene, m - and o -xylene.