31 https://uvadoc.uva.es/handle/10324/1157 2026-06-09T05:17:53Z 2026-06-09T05:17:53Z Hevia de los Mozos, Luis Fernando Sanz del Soto, Luis Felipe González López, Juan Antonio Mariano Lozano Martín, Daniel Villa Vallejo, Susana https://uvadoc.uva.es/handle/10324/84765 2026-05-25T19:12:11Z 2026-01-01T00:00:00Z

Excess molar enthalpies for iodobenzene (C6H5I), or 1-iodonaphthalene + heptane, + decane, + dodecane, or + tetradecane mixtures at 298.15 K and 93 kPa have been measured using a Tian-Calvet micro-calorimeter. The values of excess molar enthalpies are positive and indicate that interactions between like molecules are prevalent. In contrast, our previous results on excess molar volumes are negative for the systems C6H5I + heptane, or 1-iodonaphthalene + n-alkane, which reveal the existence of large structural effects in such solutions. This set of measurements has been used to determine isochoric excess molar internal energies. In the range of n-alkanes considered (n is the number of C atoms of the alkane), values of isochoric excess molar internal energies at equimolar composition decrease from n = 7 to n = 10 and then slightly increase for systems with C6H5I, while decrease slowly for mixtures with 1-iodonaphthalene. These trends fit well with the patterns observed for other alkane mixtures containing cyclic molecules. Dispersive interactions are dominant and those between aromatic molecules with a given halogen atom become stronger when the size of this atom increases due to the corresponding increase of molecular polarizability. The mixtures were studied using the DISQUAC and Flory models. The latter was also applied to n-alkane solutions with fluorobenzene (C6H5F), or 1-methylnaphthalene. Both theories describe accurately the excess molar enthalpies data. In terms of the Flory’s model, this means that the random mixing hypothesis is largely achieved. On the other hand, the theory overestimates the interactional contribution to excess molar volumes, particularly for systems with C6H5X (X=F,I).

2026-01-01T00:00:00Z Llamas, César González, Manuel A. Hernández, Carmen Vegas, Jesús https://uvadoc.uva.es/handle/10324/84492 2026-05-11T19:01:55Z 2016-01-01T00:00:00Z

Nearly every practical improvement in modeling human motion is well founded in a properly designed collection of data or datasets. These datasets must be made publicly available for the community could validate and accept them. It is reasonable to concede that a collective, guided enterprise could serve to devise solid and substantial datasets, as a result of a collaborative effort, in the same sense as the open software community does. In this way datasets could be complemented, extended and expanded in size with, for example, more individuals, samples and human actions. For this to be possible some commitments must be made by the collaborators, being one of them sharing the same data acquisition platform. In this paper, we offer an affordable open source hardware and software platform based on inertial wearable sensors in a way that several groups could cooperate in the construction of datasets through common software suitable for collaboration. Some experimental results about the throughput of the overall system are reported showing the feasibility of acquiring data from up to 6 sensors with a sampling frequency no less than 118 Hz. Also, a proof-of-concept dataset is provided comprising sampled data from 12 subjects suitable for gait analysis.

2016-01-01T00:00:00Z González, Manuel Á González, Miguel Á https://uvadoc.uva.es/handle/10324/84490 2026-05-11T19:01:54Z 2016-01-01T00:00:00Z

Modern smartphones have calculation and sensor capabilities that make them suitable for use as versatile and reliable measurement devices in simple teaching experiments. In this work a smartphone is used, together with low cost materials, in an experiment to measure the frequencies emitted by vibrating rods of different materials, shapes and lengths. The results obtained with the smartphone have been compared with theoretical calculations and the agreement is good. Alternatively, physics students can perform the experiment described here and use their results to determine the dependencies of the obtained frequencies on the rod characteristics. In this way they will also practice research methods that they will probably use in their professional life.

2016-01-01T00:00:00Z Ferri, S. Calisti, A. Mossé, C. Mouret, L. Talin, B. Gigosos, M. A. González, M. A. Lisitsa, V. https://uvadoc.uva.es/handle/10324/84488 2026-05-11T19:01:52Z 2011-01-01T00:00:00Z

A very fast method for calculating line shapes in the presence of an external magnetic field accounting for charge particle dynamics is proposed. It is based on a reformulation of the frequency fluctuation model, which provides an expression of the dynamic line shape as a functional of the static distribution function of frequencies. In the presence of an external magnetic field, the distribution of intensity and polarization of the emission depends on the angle between the observation line and the magnetic field’s direction. Comparisons with numerical simulations and experimental results for various plasma conditions show very good agreement. Results on hydrogen lines in the context of magnetic fusion and the Lyman-α line, accounting for fine structure, emitted by argon in the context of inertial fusion, are also presented.

2011-01-01T00:00:00Z González, Manuel Á Ivković, Milivoje Gigosos, Marco A Jovićević, Sonja Lara, Natividad Konjević, Nikola https://uvadoc.uva.es/handle/10324/84486 2026-05-11T19:01:52Z 2011-01-01T00:00:00Z

The broadening of the He I 447.1 nm line and its forbidden components in plasmas is studied using computer simulation techniques and the results are compared with our and other experiments. In these calculations wide ranges of electron densities and temperatures are considered. Experimental measurements are performed with a high electron density pulsed discharge and with a low electron density microwave torch at atmospheric pressure. Both calculations and experimental measurements are extended from previous works towards low electron densities in order to study the accuracy of plasma diagnostics using this line in ranges of interest in different practical applications. The calculation results are compared with experimental profiles registered in plasmas diagnosed using independent techniques. The obtained agreement justifies the use of these line parameters for plasma diagnostics. The influence of self-absorption on line parameters is also analysed. It is shown that the separation between the peaks of the allowed and forbidden components exhibits a clear dependence upon plasma electron density free of self-absorption influence. This allows the peak separation to be used as a good parameter for plasma diagnostics. From the simulation results, a simple fitting formula is applied that permits obtaining the electron number density plasma diagnostics in the range 5 × 1022 –7 × 1023 m−3 . At lower densities the fitting of simulated to experimental full profiles is a reliable method for Ne determination.

2011-01-01T00:00:00Z Calisti, A. Ferri, S. Mossé, C. Talin, B. Gigosos, M.A. González, M.Á. https://uvadoc.uva.es/handle/10324/84485 2026-05-11T19:01:51Z 2011-01-01T00:00:00Z

We present a study of statistical static and dynamic properties of local electric fields in moderately coupled hydrogen plasmas. In this regime new molecular dynamics simulations of neutral hydrogen, protons and electrons are now well controlled. They provide new insight into the statistical properties of the microfield. Taking advantage of such careful MD simulations this work focuses on a new analysis of concepts for the high and low frequency components introduced in the past in several seminal works.

2011-01-01T00:00:00Z Stambulchik, Evgeny Calisti, Annette Chung, Hyun-Kyung González Delgado, Manuel Ángel https://uvadoc.uva.es/handle/10324/84459 2026-05-08T19:01:15Z 2014-01-01T00:00:00Z

Line-shape analysis is one of the most important tools for diagnostics of both laboratory and space plasmas. Its reliable implementation requires sufficiently accurate calculations, which imply the use of analytic methods and computer codes of varying complexity, and, necessarily, varying limits of applicability and accuracy. However, studies comparing different computational and analytic methods are almost non-existent. The Spectral Line Shapes in Plasma (SLSP) code comparison workshop series [1] was established to fill this gap. Numerous computational cases considered in the two workshops organized to date (in April 2012 and August 2013 in Vienna, Austria) not only serve the purpose of code comparison, but also have applications in research of magnetic fusion, astrophysical, laser-produced plasmas, and so on. Therefore, although the first workshop was briefly reviewed elsewhere [2], and will likely be followed by a review of the second one, it was unanimously decided by the participants that a volume devoted to results of the workshops was desired. It is the main purpose of this special issue.

2014-01-01T00:00:00Z Ferri, Sandrine Calisti, Annette Mossé, Caroline Rosato, Joël Talin, Bernard Alexiou, Spiros Gigosos Pérez, Marco Antonio González Delgado, Manuel Ángel González Herrero, Diego Lara, Natividad Gomez, Thomas Iglesias, Carlos Lorenzen, Sonja Mancini, Roberto Stambulchik, Evgeny https://uvadoc.uva.es/handle/10324/84458 2026-05-08T19:01:12Z 2014-01-01T00:00:00Z

Modeling the Stark broadening of spectral lines in plasmas is a complex problem. The problem has a long history, since it plays a crucial role in the interpretation of the observed spectral lines in laboratories and astrophysical plasmas. One difficulty is the characterization of the emitter’s environment. Although several models have been proposed over the years, there have been no systematic studies of the results, until now. Here, calculations from stochastic models and numerical simulations are compared for the Lyman-α and -β lines in neutral hydrogen. Also discussed are results from the Helium-α and -β lines of Ar XVII.

2014-01-01T00:00:00Z Omar, Banaz González Delgado, Manuel Ángel Gigosos Pérez, Marco Antonio Ramazanov, Tlekkabul Jelbuldina, Madina Dzhumagulova, Karlygash Zammit, Mark Fursa, Dmitry Bray, Igor https://uvadoc.uva.es/handle/10324/84457 2026-05-08T19:01:10Z 2014-01-01T00:00:00Z

Spectral line shapes of neutral helium 3889 Å (23 S–33 P ) transition line are calculated by using several theoretical methods. The electronic contribution to the line broadening is calculated from quantum statistical many-particle theory by using thermodynamic Green’s function, including dynamic screening of the electron-atom interaction. The ionic contribution is taken into account in a quasistatic approximation, where a static microfield distribution function is presented. Strong electron collisions are consistently considered with an effective two-particle T-matrix approach, where Convergent Close Coupling method gives scattering amplitudes including Debye screening for neutral helium. Then the static profiles converted to dynamic profiles by using the Frequency Fluctuation Model. Furthermore, Molecular Dynamics simulations for interacting and independent particles are used where the dynamic sequence of microfield is taken into account. Plasma parameters are diagnosed and good agreements are shown by comparing our theoretical results with the recent experimental result of Jovićević et al. (J. Phys. B: At. Mol. Opt. Phys. 2005, 38, 1249). Additionally, comparison with various experimental data in a wide range of electron density ne ≈ (1022 − 1024 ) m−3 and temperature T ≈ (2 − 6) × 104 K are presented.

2014-01-01T00:00:00Z González Delgado, Manuel Ángel Gigosos Pérez, Marco Antonio https://uvadoc.uva.es/handle/10324/84455 2026-05-08T19:01:09Z 2009-01-01T00:00:00Z

Computer simulations permit one to calculate Stark broadened profiles for non-equilibrium plasma conditions. In this work, the dependences of some line parameters on the unbalance between electrons and ions temperatures in the plasma are shown. This method can be applied in some cases to analyze experimental conditions by comparing experimental and simulated full line profiles.

2009-01-01T00:00:00Z Bruggeman, Peter Schram, Daan González Delgado, Manuel Ángel Rego, Robby Kong, Michael G Leys, Christophe https://uvadoc.uva.es/handle/10324/84452 2026-05-08T19:01:08Z 2009-01-01T00:00:00Z

Dc-excited discharges generated in water at the tip of a tungsten wire which is located at the orifice of a quartz capillary are investigated by time-averaged optical emission spectroscopy. Two distinctive discharge modes are observed. For small conductivities of the liquid the discharge is a streamer-like discharge in the liquid itself (liquid mode). For conductivities above typically 45 μS cm−1 a large vapour bubble is formed and a streamer discharge in this vapour bubble is observed (bubble mode). Plasma temperatures and electron densities are investigated for both modes. The gas temperature is estimated from the rotational temperature of N2 (C–B) and is 1600 ± 200 K for the bubble mode and 1900 ± 200 K for the liquid mode. The rotational temperature of OH(A–X) is up to 2 times larger and cannot be used as an estimate for the gas temperature. The rotational population distribution of OH(A), ν = 0 is also non-Boltzmann with a large overpopulation of high rotational states. This discrepancy in rotational temperatures is discussed in detail. Electron densities are obtained from the Stark broadening of the hydrogen Balmer beta line. The electron densities in the liquid mode are of the order of 1021 m−3 . In the bubble mode electron densities are significantly smaller: (3–4) × 1020 m−3 . These values are compared with the Stark broadening of the hydrogen alpha and gamma lines and with electron densities obtained from current density measurements. The chemical reactivities of the bubble and liquid modes are compared by means of the hydrogen peroxide production rate.

2009-01-01T00:00:00Z Djurović, S. Ćirišan, M. Demura, A. V. Demchenko, G. V. Nikolić, D. Gigosos Pérez, Marco Antonio González Delgado, Manuel Ángel https://uvadoc.uva.es/handle/10324/84451 2026-05-08T19:01:06Z 2009-01-01T00:00:00Z

Experimental measurements of the center of the H␤ Stark profile on three different installations have been done to study its asymmetry in wide ranges of electron density, temperature, and plasma conditions. Theoretical calculations for the analysis of experimental results have been performed using the standard theory and computer simulations and included separately quadrupolar and quadratic Stark effects. Earlier experimental results and theoretical calculations of other authors have been reviewed as well. The experimental results are well reproduced by the calculations at high and moderate densities.

2009-01-01T00:00:00Z Godbert Mouret, L. Rosato, J. Capes, H. Marandet, Y. Ferri, S. Koubiti, M. Stamm, R. González Delgado, Manuel Ángel Gigosos Pérez, Marco Antonio https://uvadoc.uva.es/handle/10324/84450 2026-05-08T19:01:04Z 2009-01-01T00:00:00Z

Ion dynamics is revisited in the presence of a magnetic field. This problem is of interest for the characterization of the ITER divertor plasmas, where Zeeman–Stark line shapes are both a diagnostic tool and an ingredient in the transport codes used for radiative transfer simulations. Comparisons between ab initio simulations of Zeeman–Stark profiles and calculations performed using the computationally efficient frequency fluctuation model are presented for the Lyman a and Balmer a lines.

2009-01-01T00:00:00Z Gigosos Pérez, Marco Antonio González Delgado, Manuel Ángel https://uvadoc.uva.es/handle/10324/84446 2026-05-08T19:01:02Z 2009-01-01T00:00:00Z

Context. Stark broadening of the 447.1 line of neutral helium in a weakly coupled plasma has been studied. This spectral line has a very close forbidden component. This means it is very sensitive to the plasma electron density, which is similar to hydrogen lines, for which the Stark effect is linear. Aims. The aim of this work is to supply information to be used in the spectroscopic diagnostics of plasmas. Methods. We used computer simulations in the frame of a physical model for a plasma with weak coupling between charges. The calculation includes the so-called “ion dynamics effects” in a natural way. The electron density, the ionic and electronic temperatures, and the perturber mass were the parameters in the calculations. Results. Simulation results relate the line width, shift, shape, and especially the ratio of intensities between the allowed and forbidden components, with the plasma parameters. These results are supplied as tables of line shapes.

2009-01-01T00:00:00Z Julve‐Gonzalez, Sofía Manrique, Jose A. Veneranda, Marco Reyes‐Rodríguez, Iván Pascual‐Sanchez, Elena Sanz‐Arranz, Aurelio Konstantinidis, Menelaos Lalla, Emmanuel A. Charro, María E. Rodriguez‐Gutiez, Eduardo Lopez‐Rodríguez, José M. Sanz‐Requena, José F. Delgado‐Iglesias, Jaime Gonzalez, Manuel A. Rull, Fernando Lopez‐Reyes, Guillermo https://uvadoc.uva.es/handle/10324/84445 2026-05-08T19:00:58Z 2023-01-01T00:00:00Z

The combined analysis of geological targets by complementary spectroscopic techniques could enhance the characterization of the mineral phases found on Mars. This is indeed the case with the SuperCam instrument onboard the Perseverance rover. In this framework, the present study seeks to evaluate and compare multiple machine learning techniques for the characterization of carbonate minerals based on Raman-LIBS (Laser-Induced Breakdown Spectroscopy) spectroscopic data. To do so, a Ca-Mg prediction curve was created by mixing hydromagnesite and calcite at different concentration ratios. After their characterization by Raman and LIBS spectroscopy, different multivariable machine learning (Gaussian process regression, support vector machines, ensembles of trees, and artificial neural networks) were used to predict the concentration ratio of each sample from their respective datasets. The results obtained by separately analyzing Raman and LIBS data were then compared to those obtained by combining them. By comparing their performance, this work demonstrates that mineral discrimination based on Gaussian and ensemble methods optimized the combine of Raman-LIBS dataset outperformed those ensured by Raman and LIBS data alone. This demonstrated that the fusion of data combination and machine learning is a promising approach to optimize the analysis of spectroscopic data returned from Mars.

2023-01-01T00:00:00Z Veneranda, Marco Manrique, Jose Antonio Sanz‐Arranz, Aurelio Julve Gonzalez, Sofia Prieto Garcia, Clara Pascual Sanchez, Elena Konstantinidis, Menelaos Charro, Elena Lopez, Jose Manuel Gonzalez, Manuel Angel Rull, Fernando Lopez‐Reyes, Guillermo https://uvadoc.uva.es/handle/10324/84442 2026-05-08T19:00:55Z 2023-01-01T00:00:00Z

The SuperCam and SHERLOC instruments onboard the NASA/Perseverance rover are returning the first Raman spectra to be ever collected from another planet. Similarly, the RLS instrument onboard the ESA/Rosalind Franklin rover will collect Raman spectra from powdered rocks sampled from the subsurface of Mars. To optimize the scientific exploitation of Raman spectra returned from planetary exploration missions, tailored chemometric tools are being developed that take into account the analytical capability of the mentioned Raman spectrometers. In this framework, the ERICA research group is using laboratory simulators of SuperCam and RLS to perform representative laboratory studies that will enhance the scientific outcome of both Mars2020 and ExoMars missions. On one hand, preliminary studies proved the chemometric analysis of RLS datasets could be used to obtain a reliable semi-quantitative estimation of the main mineral phases composing Martian geological samples. On the other hand, it was proved the data fusion of Raman and LIBS spectra gathered by SuperCam could be used to enhance the discrimination of mineral phases from remote geological targets. Besides describing the models developed by the ERICA group, this work presents an overview of the complementary chemometric approaches so far tested in this field of study and propose further improvements to be addressed in the future.

2023-01-01T00:00:00Z