Investigación

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Documentos generados por los docentes e investigadores de la Universidad en su labor de investigación científica producida o editada por los departamentos y centros de la Universitat Politècnica de València.

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105 K Wide Room Temperature Spin Transition Memory Due to a Supramolecular Latch Mechanism
(American Chemical Society, 2022-08-10) Seredyuk, Maksym; Znovjyak, Kateryna; Valverde-Muñoz, Francisco Javier; da Silva, Ivan; Muñoz Roca, María del Carmen; Moroz, Yurii S.; Real, José Antonio; Dpto. de Física Aplicada; Escuela Técnica Superior de Ingeniería del Diseño; Centro de Tecnologías Físicas: Acústica, Materiales y Astrofísica; Unión Europea; Generalitat Valenciana; Universitat de València; Ministerio de Ciencia e Innovación; Ministry of Education and Science of Ukraine
[EN] Little is known about the mechanisms behind the bistability (memory) of molecular spin transition compounds over broad temperature ranges (>100 K). To address this point, we report on a new discrete Fe-II neutral complex [(FeL2)-L-II](0) (1) based on a novel asymmetric tridentate ligand 2-(5-(3-methoxy-4H-1,2,4-triazol-3-yl)-6-(1H-pyrazol-1-yl))pyridine (L). Due to the asymmetric cone-shaped form, in the lattice, the formed complex molecules stack into a one-dimensional (1D) supramolecular chain. In the case of the rectangular supramolecular arrangement of chains in methanolates 1-A and 1-B (both orthorhombic, Pbcn) differing, respectively, by bent and extended spatial conformations of the 3-methoxy groups (3MeO), a moderate cooperativity is observed. In contrast, the hexagonal-like arrangement of supramolecular chains in polymorph 1-C (monoclinic, P2(1)/c) results in steric coupling of the transforming complex species with the peripheral flipping 3MeO group. The group acts as a supramolecular latch, locking the huge geometric distortion of complex 1 and in turn the trigonal distortion of the central Fe-II ion in the high-spin state, thereby keeping it from the transition to the low-spin state over a large thermal range. Analysis of the crystal packing of 1-C reveals significantly changing patterns of close intermolecular interactions on going between the phases substantiated by the energy framework analysis. The detected supramolecular mechanism leads to a record-setting robust 105 K wide hysteresis spanning the room temperature region and an atypically large T-LIESST relaxation value of 104 K of the photoexcited high-spin state. This work highlights a viable pathway toward a new generation of cleverly designed molecular memory materials.
3D printed diffractive terahertz lenses
(The Optical Society, 2016) Furlan, Walter D.; Ferrando Martín, Vicente; Monsoriu Serra, Juan Antonio; Zagrajek, Przemyslaw; Czerwinska, Elzbieta; Szustakowski, Mieczyslaw; Dpto. de Física Aplicada; Escuela Técnica Superior de Ingeniería del Diseño; Centro de Tecnologías Físicas: Acústica, Materiales y Astrofísica; Escuela Técnica Superior de Ingeniería Agronómica y del Medio Natural; Escuela de Doctorado; Generalitat Valenciana; Ministerio de Ciencia e Innovación; National Centre for Research and Development, Polonia
[EN] A 3D printer was used to realize custom-made diffractive THz lenses. After testing several materials, phase binary lenses with periodic and aperiodic radial profiles were designed and constructed in polyamide material to work at 0.625 THz. The nonconventional focusing properties of such lenses were assessed by computing and measuring their axial point spread function (PSF). Our results demonstrate that inexpensive 3D printed THz diffractive lenses can be reliably used in focusing and imaging THz systems. Diffractive THz lenses with unprecedented features, such as extended depth of focus or bifocalization, have been demonstrated.
3D sound wave focusing by 2D internal periodic structure of 3D external cuboid shape
(Elsevier, 2019) Castiñeira Ibáñez, Sergio; Tarrazó-Serrano, Daniel; Candelas Valiente, Pilar; Minin, Oleg V.; Rubio Michavila, Constanza; Minin, Igor V.; Dpto. de Física Aplicada; Escuela Técnica Superior de Ingeniería de Telecomunicación; Centro de Tecnologías Físicas: Acústica, Materiales y Astrofísica; Escuela Técnica Superior de Ingeniería Agronómica y del Medio Natural; Agencia Estatal de Investigación
[EN] In this work, we report the focusing effect of a 2D sonic crystal cuboid. The proposed sonic composite lens is vertically extended from a 2-D flat Phononic Crystal Structure, but it is found to be able to focus waves in a three-dimensional manner. By varying the cuboid size, beam dimensions change and transverse beam width values smaller than the classical diffraction limit (~0.3 of wavelength) can be obtained. Numerical results have been obtained by Finite Element Method.
A Combination of Visible-Light Organophotoredox Catalysis and Asymmetric Organocatalysis for the Enantioselective Mannich Reaction of Dihydroquinoxalinones with Ketones
(American Chemical Society, 2019-08-02) Rostoll-Berenguer, J.; Blay, G.; Muñoz Roca, María del Carmen; Pedro, J.R.; Vila, C.; Dpto. de Física Aplicada; Escuela Técnica Superior de Ingeniería del Diseño; Centro de Tecnologías Físicas: Acústica, Materiales y Astrofísica; Agencia Estatal de Investigación; European Regional Development Fund; Ministerio de Ciencia, Innovación y Universidades
[EN] An enantioselective photooxidative Mannich reaction of dihydroquinoxalinones with ketones by the merger of organophotoredox and asymmetric organocatalysis is described. This protocol features very mild reaction conditions using simple and cheap catalysts (Eosin Y and (S)-Proline) for the synthesis of chiral quinoxaline derivatives with good to high yields (up to 94%) and excellent enantioselectivities (up to 99% ee).
A computer-assisted experiment to study the influence of the Point Spread Function in the image formation process
(IOP Publishing, 2018) Ferrando Martín, Vicente; Remón Martín, Laura; Salinas Marín, Isabel; Monsoriu Serra, Juan Antonio; Furlan, Walter D.; Dpto. de Física Aplicada; Escuela Técnica Superior de Ingeniería del Diseño; Centro de Tecnologías Físicas: Acústica, Materiales y Astrofísica; Escuela Técnica Superior de Ingeniería Agronómica y del Medio Natural; Escuela de Doctorado; Generalitat Valenciana; Ministerio de Economía y Empresa
[EN] We present a new open experimental setup assisted with LabView to be used to teach the concept of the point spread function (PSF). The PSF describes the response of an image-forming system to a point object. The PSF concept is of fundamental importance in optics since the output of an image-forming system can be simulated as the convolution of the PSF with the input object. In this work, a new graphical user interface has been developed to obtain a real-time measure of the PSF and the corresponding images provided by different lenses and pupils with different sizes and shapes. From a didactical point of view, the proposed method allows students to interpret the results in a visual and heuristic way.
A DNA-centered explanation of the DNA polymerase translocation mechanism
(Nature Publishing Group, 2017-08-08) Arias González de la Aleja, José Ricardo; Dpto. de Física Aplicada; Escuela Técnica Superior de Ingeniería de Telecomunicación; Escuela Técnica Superior de Ingeniería del Diseño; Centro de Tecnologías Físicas: Acústica, Materiales y Astrofísica; Ministerio de Economía y Competitividad
[EN] DNA polymerase couples chemical energy to translocation along a DNA template with a specific directionality while it replicates genetic information. According to single-molecule manipulation experiments, the polymerase-DNA complex can work against loads greater than 50 pN. It is not known, on the one hand, how chemical energy is transduced into mechanical motion, accounting for such large forces on sub-nanometer steps, and, on the other hand, how energy consumption in fidelity maintenance integrates in this non-equilibrium cycle. Here, we propose a translocation mechanism that points to the flexibility of the DNA, including its overstretching transition, as the principal responsible for the DNA polymerase ratcheting motion. By using thermodynamic analyses, we then find that an external load hardly affects the fidelity of the copying process and, consequently, that translocation and fidelity maintenance are loosely coupled processes. The proposed translocation mechanism is compatible with single-molecule experiments, structural data and stereochemical details of the DNA- protein complex that is formed during replication, and may be extended to RNA transcription.
A Fast, Direct Procedure to Estimate the Desorption Energy for Various Molecular Ices of Astrophysical Interest
(American Astronomical Society, 2017-06-14) Luna Molina, Ramón; Luna-Ferrándiz, Ramón; Millán Verdú, Carlos; Domingo Beltran, Manuel; Muñoz-Caro, Guillermo; Santonja Moltó, Mª del Carmen; Satorre Aznar, Miguel Ángel; Dpto. de Física Aplicada; Escuela Técnica Superior de Ingeniería Industrial; Escuela Politécnica Superior de Alcoy; Centro de Tecnologías Físicas: Acústica, Materiales y Astrofísica; Ministerio de Economía y Competitividad
[EN] Desorption energy is a relevant parameter when studying the desorption kinetics of an ice under astrophysical conditions. Values reported are generally calculated using at least a desorption experiment and a further data analysis at present. In this work the establishment of a simple rule that relates the desorption energy of a species to the temperature of its desorption peak is explored. The paper presents the results obtained from zeroth-order desorption experiments, based on the use of a quartz crystal microbalance to monitor the loss of weight during desorption of the accreted ice sample under high-vacuum conditions, of nine different molecules covering a wide range of desorption energies. During these experiments, the ice desorption rate reaches a maximum at a certain temperature depending on the molecule. The formula obtained in this study facilitates the estimation of the desorption energy and is valid for all the investigated molecules. Based on these experimental results and simulations, the theoretical expression obtained is valid to calculate desorption energy for zeroth- and first-order desorption experiments under high- or ultrahigh-vacuum conditions using different ice thickness films.
A finite element model of perforated panel absorbers including viscothermal effects
(Elsevier, 2015-04-01) Carbajo San Martín, Jesús; Ramis Soriano, Jaime; Godinho, Luis; Amado-Mendes, Paulo; Alba Fernández, Jesús; Dpto. de Física Aplicada; Escuela Politécnica Superior de Gandia; Centro de Tecnologías Físicas: Acústica, Materiales y Astrofísica
Most of the analytical models devoted to determine the acoustic properties of a rigid perforated panel consider the acoustic impedance of a single hole and then use the porosity to determine the impedance for the whole panel. However, in the case of not homogeneous hole distribution or more complex configurations this approach is no longer valid. This work explores some of these limitations and proposes a finite element methodology that implements the linearized Navier Stokes equations in the frequency domain to analyse the acoustic performance under normal incidence of perforated panel absorbers. Some preliminary results for a homogenous perforated panel show that the sound absorption coefficient derived from the Maa analytical model does not match those from the simulations. These differences are mainly attributed to the finite geometry effect and to the spatial distribution of the perforations for the numerical case. In order to confirm these statements, the acoustic field in the vicinities of the perforations is analysed for a more complex configuration of perforated panel. Additionally, experimental studies are carried out in an impedance tube for the same configuration and then compared to previous methods. The proposed methodology is shown to be in better agreement with the laboratorial measurements than the analytical approach. (C) 2014 Elsevier Ltd. All rights reserved.
A first search for coincident gravitational waves and high energy neutrinos using LIGO, Virgo and ANTARES data from 2007
(IOP Publishing: Hybrid Open Access, 2013-06) Adrián Martínez, Silvia; Ardid Ramírez, Miguel; Bou Cabo, Manuel; Ferri García, Marcelino; Larosa, Giuseppina; Martínez Mora, Juan Antonio; Astraatmadja, T.; Aubert, J.J.; Al Samarai, I.; Albert, A.; Baret, B.; André, M.; Basa, S.; Bertin, Vincent; Anghinolfi, M.; Dpto. de Física Aplicada; Escuela Técnica Superior de Ingeniería del Diseño; Escuela Técnica Superior de Ingeniería Geodésica, Cartográfica y Topográfica; Centro de Tecnologías Físicas: Acústica, Materiales y Astrofísica; Instituto de Investigación para la Gestión Integrada de Zonas Costeras; Conseil Régional Provence-Alpes-Côte d'Azur; Ministerio de Ciencia e Innovación; Conseil Régional d'Alsace; David and Lucile Packard Foundation; Foundation for Polish Science; Max Planck Society; Netherlands Organization for Scientific Research; Govern de les Illes Balears; Scottish Universities Physics Alliance; Département du Var and Ville de La Seyne-sur-Mer; Centre National de la Recherche Scientifique, Francia; National Science Foundation, EEUU; Scottish Funding Council; Australian Research Council; European Regional Development Fund; Agence Nationale de la Recherche, Francia; Generalitat Valenciana; Royal Society, Reino Unido; Leverhulme Trust; Ministerio de Educación y Ciencia; Alfred P. Sloan Foundation; Science and Technology Facilities Council, Reino Unido; Foundation for Fundamental Research on Matter, Holanda; National Authority for Scientific Research, Rumanía; Council of Scientific and Industrial Research, India; Council on grants of the President of the Russian Federation; Instituto Nazionale di Fisica Nucleare; Ministry of Science and Higher Education, Polonia; Bundesministerium für Bildung und Forschung, Alemania; Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Francia; National Aeronautics and Space Administration, EEUU
We present the results of the fi rst search for gravitational wave bursts associated with high energy neutrinos. Together, these messengers could reveal new, hidden sources that are not observed by conventional photon astronomy, particularly at high energy. Our search uses neutrinos detected by the underwater neutrino telescope ANTARES in its 5 line con guration during the period January - September 2007, which coincided with the fifth and fi rst science runs of LIGO and Virgo, respectively. The LIGO-Virgo data were analysed for candidate gravitational-wave signals coincident in time and direction with the neutrino events. No signi cant coincident events were observed. We place limits on the density of joint high energy neutrino - gravitational wave emission events in the local universe, and compare them with densities of merger and core-collapse events.
A Hydrogen-Bonded Supramolecular meso-Helix
(John Wiley & Sons, 2003-05) Blay, G.; Fernández, I.; Pedro, J. R.; Ruiz-García, R.; Muñoz Roca, María del Carmen; Cano, J.; Carrasco, R.; Dpto. de Física Aplicada; Escuela Técnica Superior de Ingeniería del Diseño; Centro de Tecnologías Físicas: Acústica, Materiales y Astrofísica; Ministerio de Ciencia y Tecnología
[EN] A new one-dimensional hydrogen-bonded polymer with a unique meso-helical structure has been prepared from the spontaneous self-assembly in the solid-state of meta-substituted phenylene dioxamic acid diethyl ester monomers. The helical nature of this molecule and its self-complementary character, through intermolecular hydrogen bonding between oxamic acid ester functions, are the two main factors responsible for the crystalline aggregation process, as confirmed by both experimental X-ray crystallographic data and theoretical ab initio calculations.
A label-free diffraction-based sensing displacement immunosensor toquantify low molecular weight organic compounds
(Elsevier, 2018) Avellá Oliver, José Miguel; Ferrando Martín, Vicente; Monsoriu Serra, Juan Antonio; Puchades Pla, Rosa; Maquieira Catala, Ángel; Dpto. de Física Aplicada; Escuela Técnica Superior de Ingeniería del Diseño; Dpto. de Química; Instituto Interuniversitario de Investigación de Reconocimiento Molecular y Desarrollo Tecnológico; Centro de Tecnologías Físicas: Acústica, Materiales y Astrofísica; Escuela Técnica Superior de Ingeniería Agronómica y del Medio Natural; Escuela de Doctorado; Generalitat Valenciana; Ministerio de Economía y Competitividad; Ministerio de Ciencia e Innovación
[EN] Herein we present a diffractometric immunosensor to quantify low molecular weight organic compounds in a label-free, simple, and sensitive fashion. The approach is based on patterning analyte analogues (haptens) on solid surfaces according to a diffractive structure, and then loading specific antibodies on them to be subsequently displaced by free analytes in solution. This displacement generates a measurable change in the diffractive response that enables to quantify the analyte concentration. In this study we address the fabrication, optimization, and assessment of these diffractive structures of biological probes and their application to the analysis of atrazine, an organic compound extensively used as pesticide. This immunosensor displays well-correlated dose-response curves that reach a detection limit of 1.1¿ng¿mL¿1 of atrazine in label-free conditions. From a general viewpoint, this study also aims to provide insights into exploiting this approach towards prospective in-field analysis and screening strategies to sense multiple low molecular weight compounds in label-free conditions.
A method for detection of muon induced electromagnetic showers with the ANTARES detector
(Elsevier, 2012-05-21) Aguilar, J. A.; Al Samarai, I.; Albert, A.; Andre, M.; Anghinolfi, M.; Anton, G.; Anvar, S.; Ardid Ramírez, Miguel; Jesus, A. C. Assis; Astraatmadja, T.; Bou Cabo, Manuel; Camarena Femenia, Francisco; Ferri García, Marcelino; Larosa, Giuseppina; Martínez Mora, Juan Antonio; Dpto. de Física Aplicada; Escuela Técnica Superior de Ingeniería del Diseño; Escuela Técnica Superior de Ingeniería Geodésica, Cartográfica y Topográfica; Escuela Politécnica Superior de Gandia; Centro de Tecnologías Físicas: Acústica, Materiales y Astrofísica; Instituto de Investigación para la Gestión Integrada de Zonas Costeras; Instituto de Instrumentación para Imagen Molecular; Ministerio de Ciencia e Innovación; Generalitat Valenciana; Agence Nationale de la Recherche, Francia; Bundesministerium für Bildung und Forschung, Alemania; Centre National de la Recherche Scientifique, Francia; Instituto Nazionale di Fisica Nucleare; Foundation for Fundamental Research on Matter, Holanda; Département du Var and Ville de La Seyne-sur-Mer; Commissariat à l'Énergie Atomique et aux Énergies Alternatives, Francia; National Authority for Scientific Research, Rumanía; Council on grants of the President of the Russian Federation; Netherlands Organization for Scientific Research
The primary aim of ANTARES is neutrino astronomy with upward going muons created in charged current muon neutrino interactions in the detector and its surroundings. Downward going muons are background for neutrino searches. These muons are the decay products of cosmic-ray collisions in the Earths atmosphere far above the detector. This paper presents a method to identify and count electromagnetic showers induced along atmospheric muon tracks with the ANTARES detector. The method is applied to both cosmic muon data and simulations and its applicability to the reconstruction of muon event energies is demonstrated. © 2012 Elsevier B.V. All rights reserved.
A model for acoustic absorbent materials derived from coconut fiber
(CSIC, 2014) Ramis Soriano, Jaime; Rey Tormos, Romina María del; Alba Fernández, Jesús; Godinho, Luis; Carbajo, Jesús; Dpto. de Física Aplicada; Escuela Politécnica Superior de Alcoy; Escuela Politécnica Superior de Gandia; Centro de Tecnologías Físicas: Acústica, Materiales y Astrofísica
[EN] In the present paper, a methodology is proposed for obtaining empirical equations describing the sound absorption characteristics of an absorbing material obtained from natural fibers, specifically from coconut. The method, which was previously applied to other materials, requires performing measurements of airflow resistivity and of acoustic impedance for samples of the material under study. The equations that govern the acoustic behavior of the material are then derived by means of a least-squares fit of the acoustic impedance and of the propagation constant. These results can be useful since they allow the empirically obtained analytical equations to be easily incorporated in prediction and simulation models of acoustic systems for noise control that incorporate the studied materials.
A Multifunctional Solution for Simultaneous Sound Insulation and Acoustic Conditioning - An Example of Application in a Radio Studio
(MDPI AG, 2022-01-26) Rodríguez-Vercher, Juan-Carlos; Alba Fernández, Jesús; Rey Tormos, Romina María del; Dpto. de Física Aplicada; Escuela Politécnica Superior de Alcoy; Escuela Politécnica Superior de Gandia; Centro de Tecnologías Físicas: Acústica, Materiales y Astrofísica; GENERALITAT VALENCIANA; Institut Valencià de Competitivitat Empresarial
[EN] In building acoustics, two different problems usually arise. There is a need to comply with established sound insulation parameters, but there are also legislative conditions concerning reverberation time. It is therefore necessary to acoustically insulate and condition the enclosures. When designing the acoustic treatment of buildings, sound insulation is always considered before acoustic conditioning. There are multiple solutions for sound insulation; one of them consists of a base wall reinforced with a plasterboard lining. The sound insulation improvement provided by these solutions will depend on the type of base wall used. A common solution for acoustic conditioning is the use of perforated plate lining systems with a plenum filled with sound absorbing material. This work presents a solution for simultaneous sound insulation and conditioning improvement, reducing the installation costs. Materials that provide the acoustic conditioning features were analyzed to validate their use in the complete solution, performing airflow resistance tests. The complete solution was also evaluated on a laboratory scale by conducting tests in a reverberation chamber and in a transmission chamber for small samples. Finally, the effectiveness of the presented solution was assessed with in-situ tests in a radio studio.
A new trifocal corneal inlay for presbyopia
(Nature Publishing Group, 2021-03-23) Furlan, Walter D.; Montagud Martínez, Diego; Ferrando Martín, Vicente; Garcia-Delpech, Salvador; Monsoriu Serra, Juan Antonio; Dpto. de Física Aplicada; Escuela Técnica Superior de Ingeniería del Diseño; Centro de Tecnologías Físicas: Acústica, Materiales y Astrofísica; Escuela Técnica Superior de Ingeniería Agronómica y del Medio Natural; Escuela de Doctorado; Generalitat Valenciana; AGENCIA ESTATAL DE INVESTIGACION; Universitat Politècnica de València
[EN] Corneal inlays (CIs) are the most recent surgical procedure for the treatment of presbyopia in patients who want complete independence from the use of glasses or contact lenses. Although refractive surgery in presbyopic patients is mostly performed in combination with cataract surgery, when the implantation of an intraocular lens is not necessary, the option of CIs has the advantage of being minimally invasive. Current designs of CIs are, either: small aperture devices, or refractive devices, however, both methods do not have good performance simultaneously at intermediate and near distances in eyes that are unable to accommodate. In the present study, we propose the first design of a trifocal CI, allowing good vision, at the same time, at far, intermediate and near vision in presbyopic eyes. We first demonstrate the good performance of the new inlay in comparison with a commercially available CI by using optical design software. We next confirm experimentally the image forming capabilities of our proposal employing an adaptive optics based optical simulator. This new design also has a number of parameters that can be varied to make personalized trifocal CI, opening up a new avenue for the treatment of presbyopia.
A novel dimer of oxo-di(acetato)-bridged manganese(III) dimers complex of potential biological significance
(Elsevier, 2000-07) Ruiz, R.; Sangregorio, C.; Caneschi, A.; Rossi, P.; Gaspar, A. B.; Real, J. A.; Muñoz Roca, María del Carmen; Dpto. de Física Aplicada; Escuela Técnica Superior de Ingeniería del Diseño; Centro de Tecnologías Físicas: Acústica, Materiales y Astrofísica; European Commission; Ministerio de Educación y Ciencia
[EN] Assembly of the tetranuclear oxomanganese(III) acetato cluster [Mn4O2(O2CMe)(7)(phen)(2)](BF4) from the dinuclear oxo-di(acetato)bridged manganese(III) species [Mn2O(O2CMe)(2)(H2O)(2)(phen)(2)](BF4)(2) . 3H(2)O in aqueous/acetic acid MeOH solution occurs via the new 'dimer of dimers' Mn-III complex [Mn2O(O2CMe)(3)(H2O)(phen)(2)](BF4) . MeOH possesing an unprecedent [Mn-4(mu-O)(2)(mu-O2Me)(4) (mu-(OH2O2CMe)-O-...)(2)] core.
A phenomenological model for sonic crystals based on artificial neural networks
(Acoustical Society of America, 2006-08) Fuster I Garcia, Elies; Romero García, Vicente; Sánchez Pérez, Juan Vicente; García Raffi, Luis Miguel; Sánchez Pérez, Enrique Alfonso; Dpto. de Física Aplicada; Escuela Técnica Superior de Ingeniería de Telecomunicación; Instituto Universitario de Tecnologías de la Información y Comunicaciones; Dpto. de Matemática Aplicada; Escuela Técnica Superior de Ingeniería Geodésica, Cartográfica y Topográfica; Instituto Universitario de Matemática Pura y Aplicada; Escuela Técnica Superior de Ingeniería de Caminos, Canales y Puertos; Escuela Técnica Superior de Ingeniería Industrial; Centro de Tecnologías Físicas: Acústica, Materiales y Astrofísica; Generalitat Valenciana; Ministerio de Educación y Ciencia
[EN] A phenomenological model that simulates the acoustic attenuation behavior of sonic crystals is developed in this paper. The input of the model is a set of parameters that characterizes each experimental setup, and the output is a simulation of the associated attenuation spectrum. The model consists of a combination of a multiresolution analysis based on wavelet functions and a set of artificial neural networks. An optimized coupling of these tools allows us to drastically reduce the experimental data needed, and to obtain a fast computational model that can be used for technological purposes. © 2006 Acoustical Society of America.
A Probabilistic Classification Procedure Based on Response Time Analysis Towards a Quick Pre-Diagnosis of Student's Attention Deficit
(MDPI AG, 2019-05) Hernaiz-Guijarro, M.; Castro Palacio, Juan Carlos; Navarro Pardo, E.; Isidro San Juan, José María; Fernández de Córdoba Castellá, Pedro José; Dpto. de Física Aplicada; Dpto. de Matemática Aplicada; Escuela Técnica Superior de Ingeniería del Diseño; Instituto Universitario de Matemática Pura y Aplicada; Escuela Técnica Superior de Ingeniería Industrial; Centro de Tecnologías Físicas: Acústica, Materiales y Astrofísica; Agencia Estatal de Investigación
[EN] A classification methodology based on an experimental study is proposed towards a fast pre-diagnosis of attention deficit. Our sample consisted of school-aged children between 8 and 12 years from Valencia, Spain. The study was based on the response time (RT) to visual stimuli in computerized tasks. The process of answering consecutive questions usually follows an ex-Gaussian distribution of the RTs. Specifically, we seek to propose a simple automatic classification scheme of children based on the most recent evidence of the relationship between RTs and ADHD. Specifically, the prevalence percentage and reported evidence for RTs in relation to ADHD or to attention deficit symptoms were taken as reference in our study. We explain step by step how to go from the computer-based experiments and through the data analysis. Our desired aim is to provide a methodology to determine quickly those children who behave differently from the mean child in terms of response times and thus are potential candidates to be diagnosed for ADHD or any another cognitive disorder related to attention deficit. This is highly desirable as there is an urgent need for objective instruments to diagnose attention deficit symptomatology. Most of the methodologies available nowadays lead to an overdiagnosis of ADHD and are not based on direct measurement but on interviews of people related to the child such as parents or teachers. Although the ultimate diagnosis must be made by a psychologist, the selection provided by a methodology like ours could allow them to focus on assessing a smaller number of candidates which would help save time and other resources.
A quantitative analysis of coupled oscillations using mobile accelerometer sensors
(European Physical Society, 2013-05) Castro Palacio, Juan Carlos; Velazquez Abad, Luisberis; Gimenez Palomares, Fernando; Monsoriu Serra, Juan Antonio; Dpto. de Física Aplicada; Dpto. de Matemática Aplicada; Escuela Técnica Superior de Ingeniería del Diseño; Instituto Universitario de Matemática Pura y Aplicada; Escuela Técnica Superior de Ingeniería Industrial; Centro de Tecnologías Físicas: Acústica, Materiales y Astrofísica; Instituto de Ciencias de la Educación, Universitat Politècnica de València
In this paper, smartphone acceleration sensors were used to perform a quantitative analysis of mechanical coupled oscillations. Symmetric and asymmetric normal modes were studied separately in the first two experiments. In the third, a coupled oscillation was studied as a combination of the normal modes. Results indicate that acceleration sensors of smartphones, which are very familiar to students, represent valuable measurement instruments for introductory and first-year physics courses.
A redox-sensitive nanofluidic diode based on nicotinamide-modified asymmetric nanopores
(Elsevier, 2017-03) Ali, Mubarak; Ahmed, Ishtiaq; Ramirez Hoyos, Patricio; Nasir, Saima; Mafe, Salvador; Niemeyer, Christof M.; Ensinger, Wolfgang; Dpto. de Física Aplicada; Escuela Técnica Superior de Arquitectura; Centro de Tecnologías Físicas: Acústica, Materiales y Astrofísica; Generalitat Valenciana; Ministerio de Economía, Industria y Competitividad
[EN] We demonstrate a redox-sensitive nanofluidic diode whose ion rectification is modulated by the oxidation and reduction of chemical moieties incorporated on its surface. To achieve this goal, we have first synthesized the chemical compounds 1-(4-aminobutyl)-3-carbamoylpyridin-1-ium (Nic-BuNH2) and 3-carbamoyl-1-(2,4-dinitrophenyl)pyridinium (Nic-DNP). Then, the surface of track-etched single asymmetric nanopores is decorated with the redox-sensitive Nic-BuNH2 and Nic-DNP molecules using carbodiimide coupling chemistry and Zincke reaction, respectively. The success of the modification reactions is monitored through the changes in the current¿voltage (I¿V) curves prior to and after pore functionalization. Upon exposing the modified pore to solutions of hydrogen peroxide (oxidizing agent) and sodium dithionite (reducing agent) the surface charge is reversibly modulated from positive to neutral, leading to measurable changes in the electronic readout of ion current passing through the nanopore. On oxidation, the quaternary nicotinamide units impart positive charge to the pore surface, resulting in the ion current rectification (anion-selective pore). On the contrary, the complementary reduced dihydronicotinamide moieties resulted in the loss of surface charge and ohmic behaviour (non-selective pore). The experimental results are further theoretically described by using Poisson-Nernst-Planck

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