Search results for " Methods"
showing 10 items of 4102 documents
High-pressure structural and vibrational properties of monazite-type BiPO4, LaPO4, CePO4, and PrPO4
2018
[EN] Monazite-type BiPO4, LaPO4, CePO4, and PrPO4 have been studied under high pressure by ab initio simulations and Raman spectroscopy measurements in the pressure range of stability of the monazite structure. A good agreement between experimental and theoretical Raman-active mode frequencies and pressure coefficients has been found which has allowed us to discuss the nature of the Raman-active modes. Besides, calculations have provided us with information on how the crystal structure is modified by pressure. This information has allowed us to determine the equation of state and the isothermal compressibility tensor of the four studied compounds. In addition, the information obtained on th…
Two Half-Truths Make a Whole? On Bias in Self-Reports and Tracking Data
2019
The pervasive use of mobile information technologies brings new patterns of media usage, but also challenges to the measurement of media exposure. Researchers wishing to, for example, understand the nature of selective exposure on algorithmically driven platforms need to precisely attribute individuals’ exposure to specific content. Prior research has used tracking data to show that survey-based self-reports of media exposure are critically unreliable. So far, however, little effort has been invested into assessing the specific biases of tracking methods themselves. Using data from a multimethod study, we show that tracking data from mobile devices is linked to systematic distortions in sel…
Towards an accurate molecular orbital theory for excited states : Ethene, butadiene, and hexatriene
1993
A newly proposed quantum chemical approach for ab initio calculations of electronic spectra of molecular systems is applied to the molecules ethene, trans‐1,3‐butadiene, and trans‐trans‐1,3,5‐hexatriene. The method has the aim of being accurate to better than 0.5 eV for excitation energies and is expected to provide structural and physical data for the excited states with good reliability. The approach is based on the complete active space (CAS) SCF method, which gives a proper description of the major features in the electronic structure of the excited state, independent of its complexity, accounts for all near degeneracy effects, and includes full orbital relaxation. Remaining dynamic ele…
Varieties of agencies during working life changes
2020
The aim of this study is to shed light on the varieties of workers´ agencies in working life change situations, which is an under-researched topic in the literature of workplace learning and in working life studies. The research questions are what kinds of agencies there are to be found when workers encounter changes and how the different kinds of agencies are connected together. The understanding of agency is grounded on the subject-centered socio-cultural approach, whereas the methodological approach is based on applying life-course perspective on research material consisting of 48 working life narratives written by Finnish adults. The narratives are analyzed by abductive content analysis…
Understanding maritime transport route choice among Irish exporters: A latent class approach
2021
Abstract The reduction in the level of maritime connectivity between Ireland and mainland Europe has been the focus of concern for Irish exporters since the withdrawal of the United Kingdom from the European Union in January 2019. In a post-Brexit scenario, new proposals are being sought to address Ireland's reliance on the UK land-bridge. Policy developments aimed at circumventing the potential negative impact of UK customs checks for Irish exports include the proposals by the European Commission to introduce new direct shipping routes connecting main ports in Ireland with Zeebrugge and Antwerp in Belgium, as well as with Rotterdam in the Netherlands. From a transport policy perspective, f…
Reactive melt blending of functionalized-MW/CNTs with polyolefin
2012
Adding nanotube adding into a polymeric matrix leads to the formulation of nanocomposites with enhanced macroscopical performances, and, moreover, the use of functionalized MW-CNTs leads to the nanocomposite formulation with even better properties. Furthermore, the reactive melt blending can be considered as a powerful processing method, i.e. reasonably simple and ecologically friendly, in order to formulate polymer based nanocomposite with good performance. In this work, the reactive melt blending between an ethylene-acrylic acid co-polymer, bis-oxazoline and functionalized MW-CNTs was performed and the rheological properties of the formulated systems were investigated.
MAST solution of advection problems in irrotational flow fields
2007
Abstract A new numerical–analytical Eulerian procedure is proposed for the solution of convection-dominated problems in the case of existing scalar potential of the flow field. The methodology is based on the conservation inside each computational elements of the 0th and 1st order effective spatial moments of the advected variable. This leads to a set of small ODE systems solved sequentially, one element after the other over all the computational domain, according to a MArching in Space and Time technique. The proposed procedure shows the following advantages: (1) it guarantees the local and global mass balance; (2) it is unconditionally stable with respect to the Courant number, (3) the so…
Evolutionary design optimization with Nash games and hybridized mesh/meshless methods in computational fluid dynamics
2012
Valoración de la ingesta dietética a nivel poblacional mediante cuestionarios individuales: sombras y luces metodológicas
2007
El desarrollo de la moderna metodología necesaria para caracterizar con rigor la ingesta de individuos y poblaciones data de hace sólo dos décadas, cuando germinó la epidemiología nutricional. La razón del carácter reciente de esta disciplina radica en el hecho de que la valoración de la ingesta dietética a nivel poblacional presenta retos complejos, que sólo van siendo superados a medida que investigamos y mejoramos los instrumentos metodológicos disponibles. En el presente artículo se revisan los métodos alternativos para estimar la ingesta de alimentos y nutrientes en los individuos. Tras una sucinta descripción de los métodos indirectos y directos de valoración del consumo alimentario, …
Bibliometric analysis through methodological quality indicators of Spanish education journals indexed in JCR during the three year period 2014-2016
2019
This study carries out a bibliometric evaluation through methodological quality indicators of the scientific production published during the triennium of 2014 to 2016 in the seven Spanish journals of education indexed in the Journal Citation Reports (JCR): Revista de Psicodidáctica; Comunicar; Revista de Educación; Educación XX1; Enseñanza de las Ciencias, Revista Española de Pedagogía; y Porta Linguarum. Through a bibliometric-descriptive methodology, a sample of articles that totals 479 and selected through a non-probabilistic sampling of deliberate type. Overall, the results obtained indicate that the journals evaluated have achieved levels of compliance with the proposed methodological …