178,021 research outputs found
Ramis Barceló, R., Derecho natural, historia y razones para actuar. La contribución de Alasdair MacIntyre al pensamiento jurídico [Reseña]
No full textReseña de la obra de Ramis Barceló, R., Derecho natural, historia y razones para actuar. La contribución de Alasdair MacIntyre al pensamiento jurídico,
Universidad Carlos III-Dykinson, Madrid,
2012, 480 pp
Comments on “what is the radiation before 5G? A correlation study between measurements in situ and in real time and epidemiological indicators in Vallecas, Madrid”
No full textNajera A, Ramis R, Las-Heras Andes F, Garcia-Pardo C, Alonso JI, Gonzalez-Rubio J, Hernando A, Martinez JL, Marcos F
Kinetic modelling of the biodegradation of polymeric materials
No full textKinetic modelling of the biodegradation of polymeric materials
Francesco Contea, Ilenia Rossettia, Gianguido Ramis b
a Dipartimento di Chimica, Università degli Studi di Milano, via C. Golgi 19, 20133, Milano, Italy
b DICCA, Università degli Studi di Genova, via all’Opera Pia 15A, 16149 Genova, Italy
[email protected]
Abstract
Methods to treat kinetic data for the biodegradation of different plastic materials are comparatively discussed [1-4]. Different commercial plastic samples were tested for biodegradation under standard testing methods in different environments. The following standard procedures have been used for kinetic data collection: i) ISO14855 for aerobic biodegradation in compost; ii) ASTM D6691 for aerobic biodegradation in marine environment; iii) ISO 15985 for anaerobic digestion with high solids content and biogas production and iv) ISO 14853 for anaerobic biodegradability in aqueous medium and production of biogas.
Starting from the raw data, the conversion vs. time entries were elaborated using relatively simple kinetic models [5], such as integrated kinetic equations of zero, first and second order, through the Wilkinson model, or using a Michaelis Menten approach, which was previously reported in the literature. The results were validated against the experimental data and allowed to correctly compute the time for half degradation of the substrate and, by extrapolation, to estimate the final biodegradation time for all the materials tested. At the same time, a comparison between the rates of CO2 emission rate during aerobic degradation vs. biogas formation rate could be established.
The reprocessing of the kinetic data by means of a model of the first order was satisfactory in most cases of aerobic biodegradation. By contrast, The reprocessing of the data for test ISO 15985 by means of a model of the first order was unsuitable. Significantly better results were obtained with a Stover-Kincannon model, which, however, has highlighted for all substrates, including cellulose used as reference, the persistence of a fraction of the material not converted. The reliability of the model is confirmed by the data collected for cellulose, for which is estimated reliably the maximum biodegradable fraction. Also in the case of the tests carried out according to ISO 14853 the most appropriate model was found to be the Stover-Kincannon one, which also in this case has highlighted the lack of complete biodegradability of all the three substrates.
Conversion (%) of the three commercial samples and reference cellulose as a function of time.
Linear regression of the conversion data for the A formulate according to a first-order model. Blue diamonds were not included in the regression pertaining to the plateau region.
References
1. S. Ghatge, Y. Yang, J.H. Ahn, H.G. Hur, Appl. Biol. Chem. 2020, 63, 1.
2. S. Fontanella, S. Bonhomme, M. Koutny, L. Husarova, J.M. Brusson, J.P. Courdavault, S. Pitteri, G. Samuel, G. Pichon, J. Lemaire, Polym. Degrad. Stab. 2010, 95, 1011.
3. E. Castro-Aguirre, R. Auras, S. Selke, M. Rubino, T. Marsh, Polym. Degrad. Stab. 2017, 137, 251.
4. F. Kawai, M. Watanabe, M. Shibata, S Yokoyama, Y. Sudate, Polym. Degrad. Stab. 2002, 76, 129.
5. I. Rossetti, F. Conte, G. Ramis, Engineering, 2021, 2, 54
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe 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
Conflitto, contrarietà, contaminazione. Per una definizione qualitativa del pensiero scolastico
No full textAbstract
Periodizations and historiographical nomenclature are always delicate and complex issues. In the case of the «second Scholasticism» this complexity, if possible, is even greater: the subject has many facets, the time frame under consideration is vast, the authors are numerous. This contribution, without delving into specific currents and authors, aims to provide a definition of the «second Scholasticism» starting from certain transversal features that seem to characterise a large part of the authors and texts that can be traced back to the early modern age scholastic thought
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
La Segunda Escolástica: una categoría historiográfica que reconsiderar
No full textThe idea already expressed by the Spanish Jesuit Juan Bautista Genér in 1776 in his Scholastica vindicata, seu Dissertatio Historico-Chronologico-Critico-Apologetica pro Theologia Scholastica of a period of decadence of the Golden Scholastica, which was followed by that of its rebirth, took shape in 1943 in the syntagm "Second scholasticism" coined by another Jesuit, Carlo Giacon, and, by now, taken to the historiographical category as it is still used today by various scholars, even though it often indicates objects of study and research spaces that do not always coincide. The contribution thus investigates the genesis of this historiographic category of "Second Scholastic" to evaluate its holding and its current "right of use"
Evaluación del desempeño de datos de reanálisis ERA5 en el modelado hidrológico mensual del río Ramis
No full textLa investigación tiene como objetivo evaluar el desempeño de datos de reanálisis ERA5 en el modelado hidrológico mensual del Río Ramis, la metodología de la cuenca del Rio Ramis ubicada en el departamento de Puno es de tipo no experimental, cuantitativo y descriptivo, el método fue la recopilación de información del Servicio Nacional de Meteorología e Hidrología del Perú (SENAMHI) y del Centro Europeo de Predicción Meteorológica a Medio Plazo (ERA5), empleando el modelo hidrológico GR2M para la simulación de caudales, evaluando su eficiencia mediante Nash Suftcliffe (NSE), el Coeficiente de correlación (r), el Sesgo relativo (BIAS) y la Raíz de error medio cuadrático (RMSE). Los resultados indican que el modelo GR2M con datos del SENAMHI en el indicador “NSE” es 0.90 para la calibración, y 0.85 para la validación, con datos de ERA5 el “NSE” es 0.79 para la calibración, y 0.69 para la validación, el indicador “r” es 0.94 para la calibración, y 0.92 para la validación, con datos de ERA5 el “r” es 0.90 para la calibración, y 0.89 para la validación, el indicador “PBIAS” es -4.43 para la calibración, y 0.57 para la validación, con datos de ERA5 el “PBIAS” es -10.26 para la calibración, y -33.28 para la validación, el indicador “RMSE” es 5.41 para la calibración, y 6.07 para la validación, con datos de ERA5 el “RMSE” es 7.06 para la calibración, y 8.79 para la validación. Las conclusiones indican que el modelo hidrológico GR2M con los datos del SENAMHI y ERA5 para simular caudales mensuales de la cuenca del Rio Ramis mediante los parámetros de eficiencia en el modelo según “NSE” presenta un muy buen ajuste y desempeño, según “r” presenta una fuerte correlación, según “PBIAS” presenta una sobrestimación, pero es aceptable, según “RMSE” presenta un buen ajuste y aceptable a los datos observados
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