El concepto de masa en la física clásica : aspectos históricos y didácticos

Different definitions of mass in classical physics are discussed in basis to their physical representation. The following questions are adressed: a) the quantitas materiae problem, b) dichotomy between inertial and gravitational masses and, c) didactic implications of the different definitíonal modalities

El debate sobre la masa relativista : el problema definicional y otros aspectos epistemológicos

Some epistemological issues concerning the controversy of relativistic mass, including the translation/incommensurability problem, are presented. Properties of classical and relativistic masses and alternative ontological, functional, relational, and operational definitions are compared, including, ab initio, an operational definition of relativistic mass. It is concluded that there are a number of reasons to maintain the concept of relativistic mass in science teaching

On-line database of voltammetric data of immobilized particles for identifying pigments and minerals in archaeometry, conservation and restoration (ELCHER database)

[EN] A web-based database of voltammograms is presented for characterizing artists' pigments and corrosion products of ceramic, stone and metal objects by means of the voltammetry of immobilized particles methodology. Description of the website and the database is provided. Voltammograms are, in most cases, accompanied by scanning electron microphotographs, X-ray spectra, infrared spectra acquired in attenuated total reflectance Fourier transform infrared spectroscopy mode (ATR-FTIR) and diffuse reflectance spectra in the UV-Vis-region. For illustrating the usefulness of the database two case studies involving identification of pigments and a case study describing deterioration of an archaeological metallic object are presented. (C) 2016 Elsevier B.V. All rights reserved.Research was conducted within the "Grupo de analisis cientifico de bienes culturales y patrimoniales y estudios de ciencia de la conservacion" Microcluster of the University of Valencia Excellence Campus. Financial support is gratefully acknowledged from the MINECO Projects CTQ2014-53736-C3-1-P and CTQ2014-53736-C3-2-P which are also supported with ERDF funds. The authors would like to thank to Gonzalo Girones Sarrio manager of GongDisseny Co. by the technical support for building the site structure and the structure of the database, Archbishop of Valencia, Dr. Ignacio Bosch Reig and Dr. Pilar Roig Picazo directors of the intervention project in the Basilica de la Virgen de los Desamparados de Valencia, the conservator Estrella Arcos Von Haartman (Quibla Restaura Company) and City Council Town of Malaga, the Museum of Archaeology of Xativa, its director Angel Velasco and the conservators Isabel Martinez Lazaro and Betlem Martinez for facilitating access to samples as well as Manuel Planes Insausti and Dr Jose Luis Moya Lopez technical supervisors of the Electron Microscopy Service of the Universitat Politecnica de Valencia where were carried out SEM-EDX analyses.Domenech-Carbo, A.; Domenech Carbo, MT.; Valle-Algarra, FM.; Gimeno-Adelantado, J.; Osete Cortina, L.; Bosch-Reig, F. (2016). On-line database of voltammetric data of immobilized particles for identifying pigments and minerals in archaeometry, conservation and restoration (ELCHER database). Analytica Chimica Acta. 927:1-12. https://doi.org/10.1016/j.aca.2016.04.052S11292

Electrocatalysis of neurotransmitter catecholamines by 2,4,6-triphenylpyrylium ion immobilized inside zeolite Y supercages

2,4,6-Triphenylpyrylium ions entrapped inside the supercages of Y zeolite exert a remarkable catalytic effect toward the electrochemical oxidation of dopamine and norepinephrine (neurotrasmitter catecholamines) in neutral aqueous media.Domenech Carbo, Antonio, [email protected]

Electrochemical discrimination of mints: The last Chinese emperors Kuang Hsu and Hsuan T'ung monetary unification

[EN] An electrochemical methodology for discriminating monetary emissions, a recurrent problem in much archaeological studies, is introduced. The method is based on the record of voltammetric signatures of cuprite and tenorite corrosion products in the patina using a minimally invasive nanosampling following the voltammetry of immobilized particles methodology. A model for the depth variation of voltammetric electrochemical parameters characterizing the composition of the corrosion patinas is presented. This model permits to rationalize electrochemical data and discriminate different monetary emissions. The application of this technique, corroborated by electrochemical impedance spectroscopy (EIS) and focusing ion beam-field emission scanning electron microscopy (FIB-FESEM-EDX), to a series of 10 cash copper coins produced around the Kuang Hsu and Hsuan Tung last Chinese emperors permits to discern different provincial mints and reveals that the monetary unification developed in this period was not uniform.Financial support from the Spanish MINECO Projects CTQ2014-53736-C3-1-P and CTQ2014-53736-C3-2-P which are also supported with ERDF funds. The Universita degli Studi di roma "La Sapienza" has granted a six-months research-scholarship (d.r.n. 965/2016 prot.n.0022041 del 31/03/2016) to the graduated Elena Montagna. The authors also wish to thank Dr. Jose Luis Moya Lopez and Mr. Manuel Planes Insausti (Microscopy Service of the Universitat Politecnica de Valencia) for technical supportDomenech-Carbo, A.; Domenech Carbo, MT.; Montagna, E.; Álvarez-Romero, C.; Lee, Y. (2017). Electrochemical discrimination of mints: The last Chinese emperors Kuang Hsu and Hsuan T'ung monetary unification. Talanta. 169:50-56. https://doi.org/10.1016/j.talanta.2017.03.025S505616

Characterizing archaeological bronze corrosion products intersecting electrochemical impedance measurements with voltammetry of immobilized particles

[EN] Application of electrochemical impedance measurements to microparticulate deposits of copper corrosion products attached to graphite electrodes in contact with 0.10 M aqueous HClO4 electrolyte is described. The impedance measurements were sensitive to the applied potential and the amount of solid sample and were modeled taking into account the contribution of the uncovered base electrode. Several pairs of circuit elements provide monotonic variations which are able to characterize different corrosion compounds regardless the amount of microparticulate solid on the electrode. Application to a set of archaeological samples from the archaeological Roman site of Gadara (Jordan, 4th century AD) permitted to establish a grouping of such samples suggesting different provenances/manufacturing techniques.Financial support from the MINECO ProjectsCTQ2014-53736-C3-1-P and CTQ2014-53736-C3-2-P which are also supported with ERDF funds and Grants ES-2012-052716 and EEBB-I-16-11558 is gratefully acknowledgedRedondo-Marugan, J.; Piquero-Cilla, J.; Domenech Carbo, MT.; Ramírez-Barat, B.; Al Sekhaneh, W.; Capelo, S.; Doménech Carbó, A. (2017). Characterizing archaeological bronze corrosion products intersecting electrochemical impedance measurements with voltammetry of immobilized particles. Electrochimica Acta. 246:269-279. https://doi.org/10.1016/j.electacta.2017.05.190S26927924

On the friction/tangential restitution problem: Independent friction-restitution modeling of sphere rebound with arbitrary spin

Most descriptions of collision events introduce coefficients of friction and tangential restitution which vary significantly with the impact angle, in contrast with the independence of the normal coefficient of restitution with this parameter. A redefinition of the coefficients of friction and tangential restitution based on the idea that friction and restitution effects can be treated as being mutually independent, provides a satisfactory description of experimental data using a ‘constant’ restitution coefficient independent on the impact angle. This independent friction-restitution modeling is developed here for the rebound of a homogeneous sphere having an arbitrary spin on a rough massive plane. The reported closure permits the interpretation of experimental data recently reported in literature

Description of Solid-to-Solid Redox Processes Based on the Voltammetry of Immobilized Particles Methodology: A Logistic Approximation

A semiempirical model to describe the voltammetry of nontopotactic solid-to-solid redox processes occurring in the voltammetry of immobilized particles (VIMP) electrochemistry is described. It is applied to the reduction of solid metal compounds to the corresponding metal in contact with suitable electrolytes. The model is based on the assumption that the transferred charge is a logistic function of the applied potential, a situation that applies for reversible redox processes involving strongly adsorbed reactants. The model satisfactorily applies to reproduce linear potential scan curves recorded for graphite electrodes modified with different lead compounds (PbO, PbCl2·2H2O, lead-tin yellow, lead white) in contact with 0.10 M H2SO4 aqueous solution

Cation and anion electrochemically assisted solid-state transformations of malachite green

[EN] The possibility of the electrochemical promotion of different solid-to-solid transformations including the performance of successive cation and anion insertion processes has been tested using malachite green, a triphenylmethane dye, in contact with aqueous NaCl electrolyte. Electrochemical data using the voltammetry of microparticles methodology reveal significant differences with the solution phase electrochemistry of the dye. Voltammetric data, combined with atomic force microscopy, focusing ion beam-field emission scanning electron microscopy, and high-resolution field emission scanning electron microscopy permit characterization of the oxidative dissolution, oxidation with anion insertion, reduction with cation insertion and reduction with anion issue processes, whose thermochemical aspects, involving separate ion and electron transport contributions, are discussed.Financial support from the Project CTQ2017-85317-C2-1-P (Ministerio de Economia, Industria y Competitividad (MINECO), Fondo Europeo de Desarrollo Regional (ERDF) and Agencia Estatal de Investigacion (AEI)), is gratefully acknowledged.Doménech-Carbó, A.; Dias, D.; Domenech Carbo, MT. (2020). Cation and anion electrochemically assisted solid-state transformations of malachite green. Physical Chemistry Chemical Physics. 22(3):1502-1510. https://doi.org/10.1039/c9cp05835dS1502151022