Ponencias (Física Aplicada II)

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  • Acceso AbiertoPonencia
    Desarrollo de nanocomposites de lignina/acetato de celulosa con una potencial aplicación como agente espesante en la elaboración de grasas lubricantes
    (2022) Rubio Valle, José Fernando; Martín Alfonso, Manuel Antonio; Valencia Barragán, Concepción; Martín Alfonso, José Enrique; Franco Gómez, José María; Universidad de Sevilla. Departamento de Física Aplicada II; Ministerio de Educación y Ciencia (MEC). España
    El presente trabajo se centra en el desarrollo de nanocomposites de lignina kraft de eucalipto (EKL)/acetato de celulosa (CA) empleando la técnica de electrohilado, dichas nanoestructuras tienen una potencial aplicación como agente espesante para la elaboración de grasas lubricantes. Las propiedades fisicoquímicas las distintas disoluciones elaboradas de EKL/CA se caracterizaron mediante ensayos reológicos, de tensión superficial y de conductividad eléctrica, por otro lado, las propiedades morfológicas de las nanoestructuras electrohiladas se obtuvieron mediante microscopía electrónica de barrido. Los resultados denotan que las propiedades morfológicas de las nanoestructuras electrohiladas depende principalmente de las propiedades fisicoquímicas de la disolución. Por otro lado, se llevó a cabo la caracterización morfológica, reológica y tribológica de los oleogeles obtenidos a partir de la dispersión de las membranas electrohiladas en aceite de ricino. Como resultado de dicha caracterización se obtuvo que las propiedades reológicas de los oleogeles pueden adaptarse modificando la relación EKL/CA y el contenido de nanocomposite empleado en la dispersión. Como conclusión general, el electrospinning de disoluciones de EKL/CA puede proponerse como un método sencillo y eficaz para producir olegeles lubricantes, con propiedades similares a las grasas convencionales.
  • Acceso AbiertoPonencia
    Desarrollo de dispersiones de pasta de celulosa acetilada y aceite vegetal para aplicaciones lubricantes: influencia de la temperatura de reacción
    (2022) Trejo Cáceres, Manue; Martín Alfonso, Manuel Antonio; Sánchez Carrillo, María del Carmen; Valencia Barragán, Concepción; Martín Alfonso, José Enrique
    The aim of this work was to develop stable gel-like dispersions based on acetylated cellulose pulps and castor oil. For this purpose, the pulps were acetylated and the influence of the temperature of the acetylation reaction on the final properties of the dispersions was studied. For the reaction, kraft cellulose pulp was used with a ratio (1:15) of acetic anhydride and sulphuric acid (catalyst), varying the reaction temperature (20, 40, 60, 80 y 100ºC), during 5 hours. The acetylated pulps were characterized by thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR) and the degree of substitution was obtained by heterogeneous saponification and subsequent inverse titration with HCl to determine the percentage of acetyl groups. Then, the dispersions were obtained and rheologically characterized. The results showed that the temperature of reaction has a great influence on the values of the degree of substitution of pulps and obviously, on the rheological properties of the dispersions.
  • Acceso AbiertoPonencia
    La acústica en las iglesias postconciliares de Miguel Fisac: Santa Ana de Moratalaz
    (Sociedad Española de Acústica, 2011) Bueno López, Ana María; León-Rodríguez, Ángel Luis; Galindo del Pozo, Miguel; Universidad de Sevilla. Departamento de Física Aplicada II; Universidad de Sevilla. Departamento de Construcciones Arquitectónicas I (ETSA)
    D. Miguel Fisac (1913-2006) was one of the Spanish architects of the XX century by more concerned and conscious with the aspects of acoustic spaces ecclesial projected. One of his most iconic was the church of Santa Ana Moratalaz built in Madrid between 1965 and 1971 which followed the liturgical determinations made by Vatican II. This paper describes the acoustic behavior of the same, and their relationship with their structural characteristics, spatial and so unique coating materials
  • Acceso AbiertoPonencia
    Ozone production using nanosecond-pulse and AC driven DBD in mixtures of oxygen and argon
    (2021) Fernández Rueda, A.; Pontiga Romero, Francisco de Paula; Baadj, Salim; Belasri, Ahmed; Guemou, M’hamed; Universidad de Sevilla. Departamento de Física Aplicada II; Ministerio de Ciencia, Innovación y Universidades (MICINN). España; European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER); Universidad de Sevilla. FQM253: Electrohidrodinámica y Medios Granulares Cohesivos
    Ozone (O3) in a strong oxidizing agent with many industrial applications, such as bleaching, water disinfectant treatment, elimination of odors, etc . It can be produced in electrical discharges and, particularly, dielectric barrier discharge (DBD) is commonly used in large installations. Reducing the energy cost of ozone production is of prime importance in industrial applications and, among other factors, the voltage waveform used in stimulation of the DBD is known to play an important role. Therefore, it is of interest to determine which stimulation provides the best electrical energy conversion to promote the chemical reactions that maximize the ozone yield with the highest energy efficiency. In this work, the energy efficiency of ozone production using DBD fed with pure oxygen (O2) and with a mixture of 50 % oxygen and 50 % argon (Ar) has been investigated. Two different forms of stimulation have been used: AC and pulses of nanosecond duration.
  • Acceso AbiertoPonencia
    Measurement of 210Pb and its application to evaluate contamination in an area affected by NORM releases
    (American Institute of Physics, 2008-08-07) Mosqueda Peña, Fernando; Villa Alfageme, María; Hurtado Bermúdez, Santiago José; Absi, Abdeslam; Manjón Collado, Guillermo; Vaca Galán, Federico; García-Tenorio García-Balmaseda, Rafael; Universidad de Sevilla. Departamento de Física Aplicada II; Universidad de Sevilla. RNM138: Física Nuclear Aplicada
    Liquid scintillation counting (LSC) is an easy and straightforward technique, and combined with its low limit of detection, makes it a powerful tool for both routine and low level measurements that can be applied to 210Pb low level counting in environmental samples. 210Pb can be easily measured following a sulphate co-precipitation method; the addition of a carrier and the weighing of the recovered amount is a widespread technique to evaluate radiochemical yield, however, this evaluation of the recovery is sometimes questioned. The samples employed in this work were recollected in 1999 and 2005 from the estuary of the Odiel and Tinto rivers (SW of Spain), which were affected by phosphogypsum (pg.) discharges until 1998. Phosphogypsum contains most of the 210Pb from the treated raw material, for that reason analysed riverbed sediments have enhanced 210Pb activity concentrations and hence, enhanced activity concentration of its daughter ^'"Po, both in secular equilibrium after two years.
  • Acceso AbiertoPonencia
    Virtual acoustics of the roman theatre of Malacca
    (Sociedade Portuguesa de Acústica, 2020) Nieves Pavón, Francisco José; Romero Odero, José Antonio; Alayón Perdomo, Javier; Galindo del Pozo, Miguel; Peral López, José; Girón Borrero, Sara; Universidad de Sevilla. Departamento de Historia, Teoría y Composición Arquitectónicas; Universidad de Sevilla. Departamento de Física Aplicada II
    En Hispania (actualmente España y Portugal), hay documentadas 25 estructuras de teatros clásicos romanos al aire libre, de las cuales 10 están el sur, en la Bética romana (Andalucía). La Bética se abrazó al progreso de las urbes en la época del emperador romano Augusto donde los teatros se construyeron en piedra como focos de entretenimiento, espectáculos y propaganda del imperio. El teatro romano de Málaga son los restos arqueológicos del principal vestigio de la Malaca romana. Está situado en el centro histórico de la ciudad, a los pies de la colina de la Alcazaba musulmana y fue descubierto en 1952. Se trata de un teatro de medianas dimensiones cuyo diseño corresponde a una construcción mixta que combina el aprovechamiento de la ladera del cerro para el graderío, al modo de los teatros griegos, con una importante construcción allí donde la roca es inexistente, creando el espacio necesario para las gradas. En este trabajo se analiza el proceso de producción, ajuste y validación del modelo 3D del teatro para la creación de un modelo numérico predictivo de su campo sonoro
  • Acceso AbiertoPonencia
    Geochronology of recent sediments from the Cariaco Trench (Venezuela) by Alpha Spectrometry of 210Pb (210Po)
    (American Institute of Physics, 2010) Arriojas, Argenis; Barros, Haydn; Palacios, Daniel; Hurtado Bermúdez, Santiago José; Villa Alfageme, María; Pérez, Kriss; Alfonso, Juan Andrés; Sajó-Bohus, László; Universidad de Sevilla. Departamento de Física Aplicada II; Universidad de Sevilla. RNM138: Física Nuclear Aplicada
    210Pb concentration in marine sediments of the Cariaco Trench (North‐East of Venezuela) was measured through the analysis of 210Po alpha emissions, which can be assumed to be in secular equilibrium with 210Pb. The analysed sediment core has a length of 1.9 m. The results allowed to apply the CF:CS dating model (Constant Flux and Constant Supply). The sedimentation rate was estimated to be 0.25 cm/y. As far as we know this is the first α‐ dating carried out in the country, performed with an alpha spectrometer recently funded by the IAEA.
  • Acceso AbiertoPonencia
    Sound perception in 3d virtual environments: Application to a Roman theatre of Hispania
    (Springer, 2021) Alayón Perdomo, Javier; Romero Odero, José Antonio; Galindo del Pozo, Miguel; Nieves Pavón, Francisco José; Girón Borrero, Sara; Universidad de Sevilla. Departamento de Física Aplicada II; Ahram, Tareq; Taiar, Redha; Langlois, Karine; Choplin, Arnaud; European Commission (EC). Fondo Europeo de Desarrollo Regional (FEDER); Ministerio de Economia, Industria y Competitividad (MINECO). España; Universidad de Sevilla. TEP130: Arquitectura, Patrimonio y Sostenibilidad: Acústica, Iluminación, Óptica y Energía
    The aim of this work is to present the methodology implemented for the assessment of the human perception of sound and of the degree of acoustic comfort of occupants in an ancient Roman theatre. The evaluation is carried out through a visual and acoustic experience in a virtual environment. The textured 3D visual model of the space, and the binaural auralisations based on either on-site empirical measurements or on acoustic simulations, are displayed in a listening room designed with a very short reverberation time and low background noise. By means of sophisticated equipment for 3D virtual environment reproduction to groups of people, this listening room enables the physical ambience to be recreated of the Roman theatre of Cartagena, which is located in the southeast of Hispania (Spain). Groups of people can therefore subjectively assess the intelligibility of speech and the clarity for music of this open-air performance venue. The results accentuate the strong correlation between audio and visual perceptual aspects and contribute towards a more comprehensive understanding of the architectural aural experience.
  • Acceso AbiertoPonencia
    Physico-chemical modeling of positive corona discharge in carbon dioxide
    (Institute of Electrical and Electronics Engineers (IEEE), 2010) Yanallah, K.; Pontiga Romero, Francisco de Paula; Moreno González, H.; Castellanos Mata, Antonio; Universidad de Sevilla. Departamento de Física Aplicada II; Ministerio de Ciencia y Tecnología (MCYT). España; Junta de Andalucía; Agencia Española de Cooperación Internacional para el Desarrollo (AECID); Universidad de Sevilla. FQM253: Electrohidronámica y Medios Granulares Cohesivos
    Positive wire-to-cylinder corona discharge in pure CO2 has been simulated using a model that includes elementary plasma processes (ionization, electron attachment and detachment, ion recombination, etc.) and chemical reactions between neutral species. The plasma chemistry model is included in the continuity equations of species, which are coupled with Poissons equation for the electric field and the energy conservation equation for the gas temperature. The experimental values of voltage and current are used as input data into the numerical simulation, and the spatial distributions of electrons, ions, atoms and molecules are then predicted for different gas flow rates. The average concentrations of ozone and carbon monoxide inside the discharge reactor have been experimentally determined by means of ultraviolet and FTIR spectrometry, and their values are compared with the results of the numerical simulation.
  • Acceso AbiertoPonencia
    Weak measurements for reutilizing entanglement
    (2020) Foletto, Giulio; Calderaro, Luca; Tavakoli, Armin; Schiavon, Matteo; Picciariello, Francesco; Cabello Quintero, Adán; Villoresi, Paolo; Vallone, Giuseppe; Universidad de Sevilla. Departamento de Física Aplicada II; Universidad de Sevilla. FQM239: Fundamentos de Mecánica Cuántica
    Weak measurements are a relevant tool for quantum information because they allow tuning the disturbance on the observed state and the amount of information extracted from it. They can be used to harness repeatedly a quantum resource from the same state, thus boosting the performance of many protocols. We verified experimentally that sequences of weak measurements can generate correlations strong enough to violate the CHSH inequality multiple times, and yet can leave the state entangled enough for the next CHSH test. This means that entanglement can be certified and utilized more times, which is important for fundamental tests of quantum theory and above all for deviceindependent quantum information.
  • Acceso AbiertoPonencia
    A three-scales model for the dispersion of radioactive spots from nuclear emergencies. Application to the Baltic Sea after the accident of Chernobyl
    (Marine Technology Society, 2004) Toscano Jiménez, Manuel; García-Tenorio García-Balmaseda, Rafael; Universidad de Sevilla. Departamento de Física Aplicada II; Universidad de Sevilla. Departamento de Física Aplicada III
    This model is a improved version of a previously published Two-Scales model 1111 and includes the transport of particles in three spatial scales: small (kilometres), medium (decades of km), and large (hundreds of km). A 3-D dispersion model has been developed to analyse and simulate the dispersion of nuclear contaminants in marine ecosystems. This model is characterized by presenting high spatial resolution, by taking into account the possible binding of a fraction of the Contaminants to the suspended matter as well as its consequent sedimentation, and especially by formulating the diffusion processes using an original approach. The horizontal resolution of the model is 20 km, while for the vertical resolution a total of six layers are considered. The Baltic Sea has heen elected as the validation scenario of the model and the radionuclide Cs-137 as the radiotracer to be analysed. This scenario was the most contaminated ecosystem out of the Sonet Union due to the Chernohyl accident occurred at the end of April 1986, and the elected radiotracer Cs-137 was the main long-lived radioisotope emitted to the environment. A computation time of approximately 9 hours by using a Matlab code in a personal computer (AMD-1.4 GHz) was necessary. Different classical tools in Oceanography as well as different numerical methods (Monte Carlo, Finite differences) have been properly implemented in the model. The approaches adopted allow to save a lot of computational time [lo]
  • Acceso AbiertoPonencia
    Contribución relativa del déficil mensual de precipitación a los periodos de sequía en el suroeste peninsular
    (2004) García Barrón, Leoncio; Camarillo Naranjo, Juan Mariano; Sousa Martín, Arturo; Universidad de Sevilla. Departamento de Biología Vegetal y Ecología; Universidad de Sevilla. Departamento de Geografía Física y Análisis Geográfico Regional; Universidad de Sevilla. Departamento de Física Aplicada II
    En este estudio pretendemos establecer el comportamiento de la precipitación mensual durante los periodos de sequía, y establecer si estadísticamente la disminución relativa es proporcionada, o bien, si el efecto del déficit pluviométrico es más marcado en determinados meses. Nos basamos en la serie pluviométrica de Riotinto (37º 42 ́N, 6º 36 ́W) a lo largo del siglo XX, homogénea, de clara influencia atlántica, y representativa del suroeste peninsular. Se analiza la constancia de la contribución al déficit pluviométrico a lo largo de la año, y en consecuencia si es admisible realizar aproximaciones predictivas sobre la precipitación total en cada anualidad a partir las precipitaciones acumuladas mensuales.
  • Acceso AbiertoArtículo
    Caracterización pluviométrica intraanual de la Península Ibérica
    (Asociación Española de Climatología, 2010) García Barrón, Leoncio; Camarillo Naranjo, Juan Mariano; Morales González, Julia; Sousa Martín, Arturo; Universidad de Sevilla. Departamento de Biología Vegetal y Ecología; Universidad de Sevilla. Departamento de Geografía Física y Análisis Geográfico Regional; Universidad de Sevilla. Departamento de Física Aplicada II; Ministerio de Educación y Ciencia (MEC). España
    Un aspecto destacable en el conocimiento del clima es la determinación del régimen pluviométrico intraanual. Multitud de procesos ambientales y sociales se encuentran en estrecha vinculación con el comportamiento que a lo largo del año presentan las precipitaciones. En la Península Ibérica el análisis del régimen intraanual es un instrumento de categorización climática, por el que el dominio mediterráneo predominante queda fragmentado en un conjunto de subdominios. El método de caracterización aplicado se basa en parámetros de centralización G y concentración R por momentos de primer y segundo orden de la distribución intraanual de los promedios mensuales de precipitación. La finalidad de este análisis es establecer una parametrización pluviométrica en cada observatorio estudiado para clasificar y, posteriormente, elaborar una cartografía peninsular con indicación del comportamiento de las distintas zonas pluviométricas.
  • Acceso AbiertoPonencia
    Measurement of activity concentration of polonium-210 in species of the phylum Mollusca, Tabasco, Mexico
    (AIP Publishing, 2021-04) Mandujano García, C. D.; Nava Huerta, A. R.; Ardisson, P. L.; Huerta García, J.; Vioque Romero, Ignacio; García-Tenorio García-Balmaseda, Rafael; Universidad de Sevilla. Departamento de Física Aplicada II; Universidad de Sevilla. RNM-138: Física Nuclear Aplicada
    The activity concentration of polonium-210 in the soft tissue of several species of mollusks of coastal areas from Tabasco, Mexico, has been determined. Polonium-210 is a natural radionuclide that may be bioaccumulated by flora and fauna, particularly by mollusks. Radioecological evaluation of polonium-210 in mollusks is of particular interest for environmental radioactivity surveillance and to understand the mechanisms of migration of this radionuclide from the environment to humans. In this work, an analysis of the levels of polonium-210 in mollusks from Mexico is presented. Methods include the use of alpha-particle spectrometry to measure polonium-210 in the soft tissue of the studied mollusks. Results show an average value of 158 Bq/kg in mollusks from Tabasco, Mexico. Mollusks from the taxonomic class Bivalvia bioaccumulate more polonium-210 than Gastropods. The activity concentration values of polonium-210 in mollusks from Mexico are of the same order as those reported internationally. A further work on the mechanisms of migration and bioaccumulation of polonium in these organisms is necessary.
  • Acceso AbiertoPonencia
    Enhancement of fast CO2Capture by a Nano-SiO2/CaO composite atCa-Looping conditions
    (CHISA, 2012) Valverde Millán, José Manuel; Perejón Pazo, Antonio; Pérez Maqueda, Luis Allan; Universidad de Sevilla. Departamento de Física Aplicada II
    In this paper we show the performance of a new CO2sorbentconsisting of a dry physical mixture of a Ca-based sorbent and a SiO2nanostructuredpowder. Thermo-gravimetric analysis (TGA) performed at conditions close to the Ca-looping process demonstrate that the rate of CO2capture by the mixture is enhancedduring the fast carbonation stage of practical interest in applications. Moreover, theresidual capture capacity of the mixture is increased. SEM/EDX, physisorption, andXRD analyses indicate that there is a relevant interaction between the nanostructuredSiO2skeleton and CaO at high temperatures, which serves to improve the efficiency ofthe transfer of CO2to small reactive pores as well as the stability of the sorbent porestructure
  • Acceso AbiertoPonencia
    Characterization of Porous materials as radon source and its radiological implications
    (AIP Publishing, 2008) López Coto, I.; Bolívar, Juan Pedro; Más, J. L.; García-Tenorio García-Balmaseda, Rafael; Universidad de Sevilla. Departamento de Física Aplicada II
    In this work, a magnitude is proposed in order to compare the potential radiological risk due to radon exposition generated by different materials, and a method based in the ^^^Rn accumulation technique is presented for its determination.. The obtained results indicate that the proposed magnitude and their corresponding measurement methodology are useful in order to take decisions about the management of different kinds of porous materials.
  • Acceso AbiertoPonencia
    Valorization of NORM waste from titanium dioxide industry through commercial products
    (2018) Bolívar, Juan Pedro; Gázquez, M.J.; Pérez Moreno, S.; García-Tenorio García-Balmaseda, Rafael; Vaca, F.; Universidad de Sevilla. Departamento de Física Aplicada II
  • Acceso AbiertoPonencia
    Occupational exposures and distribution of natural radionuclides in phosphoric acid production by the wet process (Spain)
    (2005-10) Bolívar, Juan Pedro; Pérez Moreno, J. P.; Martín, J. E.; Más, J. L.; García-Tenorio García-Balmaseda, Rafael; Universidad de Sevilla. Departamento de Física Aplicada II; Spanish National Security Council (CSN), I+D programme 2004-2007
    The industries devoted to the production of phosphoric acid use as a raw material large amount of phosphate rock (PR), which– depending on its geological origin –could be enriched in natural radionuclides either from the uranium or thorium series. In addition, and depending of the process used, different by-products also enriched in natural radionuclides are formed. For this reason, these types of industries are considered as one of the most representative examples where NORM and TENORM is handled, and consequently where a detailed radiological study for protection of the workers is needed.In Spain, a quite large industrial complex is located in an estuary in the surroundings of Huelva town (SW of Spain, see Figure 1), with two big factories devoted to the production of phosphoric acid through the so-called “wet-acid process” (see details in Section 2). In these factories, two types of phosphatic ores are processed: a) sedimentary marine origin phosphate ore from Morocco, and b) igneous origin phosphate ore from Kola (Russia). The Moroccan phosphorites are characterised for their high uranium concentrations, ranging 100-150 ppm, while the igneous phosphate rocks from Kola have clearly lower levels of this element. In opposition, the Kola phosphate rocks present concentrations of the 232Th-series in a factor up to 3 to 5 higher than in word average soils, while the Moroccan phosphorites contain clearly lower concentrations from this natural series [1]In both raw materials, both the 238Uand the 232Th are in secular equilibrium with their daughters. Nevertheless, during the application of the industrial process, the aforementioned secular equilibrium is broken, suffering the different radionuclides their redistributions between intermediate products according to their respective chemical characteristics [2]. This fact need to be taken into consideration for a proper radiological study inside the factories.
  • Acceso AbiertoPonencia
    Time evolution of activity concentration of natural emitters in a scenario affected by previous phosphogypsum contamination
    (2008-09) Villa Alfageme, María; Mantero Cabrera, Juan; Mosqueda Peña, Fernando; Hurtado Bermúdez, Santiago José; Manjón Collado, Guillermo; Vaca, Francisco; García-Tenorio García-Balmaseda, Rafael; Universidad de Sevilla. Departamento de Física Aplicada II
    The estuary formed by the confluence of Tinto and Odiel river-mouths is located in the South of Spain, close to Huelva town. This estuary has been deeply studied through the years because it has a double particularity. On one hand, since the beginning of the 1960s, the estuary has been affected by direct and indirect phosphogypsum (pg.) releases from two phosphoric acid and fertilizers factories that are working in the area. On the other hand, the pyrite mining operations upstream the Odiel and Tinto rivers has caused historically the formation of H2SO4, through oxidation of the natural sulphur deposits, the acidification of the waters and the consequent mobilisation of heavy metals from the mining area to the Huelva estuary. As a consequence, enhancement contamination levels in natural emitters from the ^'*U series were found in the surroundings of the factories in the previous years to 1998. However, in 1998 the management policy of waste releases drastically changed in the area, and direct discharges to Tinto and Odiel River had to be ceased. A thorough study of the affected zone is being carried out. Riverbed sediments and water samples have been analyzed from four different sampling campaigns in the estuary during the years 1999, 2001, 2002 and 2005. Different radioanalytical techniques have been employed to obtain the activity concentrations of U-isotopes, Th-isotopes, ^^^Ra, ^'"Pb and ^'"Po. Furthermore, the results for the rates of de-contamination of the area are presented. This data will be discussed in order to establish the present status of the contamination in the area, and moreover, to predict the time-evolution of the self-cleaning
  • Acceso AbiertoPonencia
    Radionucléidos naturales en un perfil de columna de agua en el lago de la corta minera de San Telmo (so de España)
    (2019-06) Mantero, Juan; Mendieta Mendoza, Aurora; Ruíz Cánovas, Carlos; Galván Moreno, José Antonio; Vioque, Ignacio; Manjón, Guillermo; García-Tenorio García-Balmaseda, Rafael; Universidad de Sevilla. Departamento de Física Aplicada II