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Experimental Design for Mixture Studies
No full textThis article focuses on the design and analysis of experiments with mixtures, very commonly involved in product development whenever a multicomponent system is concerned. Here, classical and computer-aided designs for mixture studies are introduced and discussed with various numerical examples. In fact, the strategies, which may be adopted by the experimenter for the construction of blending models in the region of interest, are quite different. The use of various methods and techniques for analysis and optimization are here illustrated by some case studies taken from practical experiences to analyse step by step the procedures adopted for the experimentation and the analysis of mixture data
Melt granulation in a high shear mixer: optimization of mixture and process variables using a combined experimental design
No full textScreening of high shear mixer melt granulation process variables using an asymmetrical factorial design
No full textThe effects of process conditions on the granulometric characteristics of a placebo formulation prepared in a 10 l high shear mixer by single-step melt granulation were studied. The factors under investigation were: binder grade, mixer load, presence of the deflector (all of analysed at two levels), binder concentration, impeller speed, massing time, type of impeller blades (these four at three levels) and jacket temperature (considered at four levels). Two granule characteristics were analysed: the geometric mean diameter and the percentage of particles finer than 315 μm. In order to screen simultaneously the above-mentioned factor levels, an asymmetrical factorial design was adopted, which allowed the reduction in the number of runs from 2592 to 25. Additionally, this technique permitted the selection of the factor levels which have the major 'weight' on the two granule characteristics under study. Two additional trials were performed to attest the screening validity
Apport de la Méthodologie de la Recherche Expérimentale àun modèle de la température de transition vitreuse de polymères acryliques et méthacryliques
No full textD-optimal design has been used for constructing a experimental database required to set up a high quality model. We show that using a priori statistics criteria (i.e., before making the experiences) it is possible to select the minimum number of molecules required to set up the database. Using the same tools, and the previous results, it is possible to evaluate the quality of the predicted value for a set of new candidates and decide whether or not they have to be taken into account in the database
Improving an EVM QSPR model for glass transition temperature prediction using optimal design
No full textExperimental design in the development of voltammetric method for the assay of omeprazole
No full textA multivariate strategy was used to optimize an adsorptive stripping voltammetric method for the determination of the antiulcer drug omeprazole. A 3/4 matrix was used for the variable screening while a central composite design was chosen in the subsequent step to evaluate the response surfaces. Simultaneous optimization of the response peak height (h(p)) and peak half width w(1/2)), the latter being a peak shape measure, was achieved. The factors accumulation time, pulse amplitude, scan rate and stirring rate were all found to be statistically significant for the response h(p), while for the response w(1/2) only the stirring rate was found to be significant. The optimized method shows a good linearity between peak height and analyte concentration in the concentration range from 8.33 x 10-9 M to 1.42 x 10- 7 M with a LOD of 6.5 x 10-9 M. The mean recovery of omeprazole in capsules was 101.9% with a SD of 2.04 (RSD = 200)
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
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