Browsing by Subject "Modelling"

Now showing 1 - 6 of 6
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    A simplified kinetic model to describe the solvent-free enzymatic synthesis of wax esters
    (2021-04-17) Serrano-Arnaldos, M.; Murcia, M.D.; Ortega Requena, Salvadora; Montiel, M.C.; Máximo, F.; Gómez, E.; Bastida, J.; Ingeniería Química
    BACKGROUND: The use of biotechnological processes at industrial scale is a promising tool to replace conventional synthesis as an efficient and eco-friendly technology. For that purpose, the kinetic modelling of an in-lab optimized enzymatic process prior to scaling-up is of great utility. RESULTS: In this work, a kinetic model for the solvent-free synthesis of cetyl laurate, myristate, palmitate and stearate using different commercial immobilized lipases has been developed. In order to describe the esterification process of the cetyl esters separately and as a mixture similar to natural spermaceti, a pseudo-first-order kinetic has been proposed and tested. A relation between the inverse values of the kinetic constant and the amount of biocatalyst has been observed. The effect of temperature on the reaction rate can be accurately described by the Arrhenius equation except for immobilized Thermomyces lanuginosus, which appears to be less resistant to temperatures above 70 °C. CONCLUSION: Low deviations between experimental and predicted values (R2 ≥ 0.99) indicate that this pseudo-first-order kinetic model can be considered valid for the data range studied. In addition, the reaction rate of spermaceti can be successfully predicted through a weighted average of the kinetic constants obtained during the synthesis of each cetyl ester. This simple but accurate kinetic model for describing the solvent-free enzymatic biosynthesis of wax esters from spermaceti may contribute to extending the application of lipases as industrial catalysts.
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    An Interactive Tool for Simulation of Biological Models Into the Wastewater Treatment With Microalgae
    (Frontiers Media, 2021-07-28) Guzmán Sánchez, José Luis; Fernández Sevilla, José María; Acién Fernández, Francisco Gabriel; Sánchez Zurano, Ana; Ingeniería Química
    Este trabajo presenta una novedosa herramienta de simulación para comprender y analizar modelos biológicos para procesos de tratamiento de aguas residuales utilizando microalgas. Los modelos para este tipo de procesos son muy complejos de analizar debido a los muy diferentes fenómenos, variables y parámetros involucrados. El modelo ya incluido en la herramienta ha sido validado en condiciones controladas que simulan las condiciones exteriores, resultando útil para simular cultivos reales al aire libre. La principal contribución de la herramienta propuesta es que estos modelos pueden simularse y compararse de manera fácil e interactiva. La herramienta permite simular modelos biológicos considerando solo microalgas o incluyendo el consorcio microalgas-bacterias. Además, las simulaciones se pueden realizar utilizando únicamente la contribución de la radiación solar o agregando los efectos ambientales y bacterianos como términos cardinales. Asimismo, se pueden evaluar los efectos de las propiedades de las aguas residuales o de diferentes cepas de microalgas. Las simulaciones interactivas se pueden realizar para días seleccionados como representativos de las diferentes estaciones del año que ya están precargadas en la herramienta. Sin embargo, el usuario también puede cargar datos de otras ubicaciones para simular los modelos en condiciones particulares.
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    Application of a diffusion-reaction kinetic model for the removal of 4-chlorophenol in continuous tank reactors
    (Taylor and Francis Group, 2014-03-03) Murcia Almagro, María Dolores; Gómez Gómez, María; Bastida Rodríguez, Josefa; Hidalgo Montesinos, Asunción María; Montiel Morte, María Claudia; Ortega Requena, Salvadora; Ingeniería Química
    A continuous tank reactor was used to remove 4-chlorophenol from aqueous solutions, using immobilized soybean peroxidase and hydrogen peroxide. The influence of operational variables (enzyme and substrate concentrations and spatial time) on the removal efficiency was studied. By using the kinetic law and the intrinsic kinetic parameters obtained in a previous work with a discontinuous tank reactor, the mass-balance differential equations of the transient state reactor model were solved and the theoretical conversion values were calculated. Several experimental series were used to obtain the values of the remaining model parameters by numerical calculation and using an error minimization algorithm. The model was checked by comparing the results obtained in some experiments (not used for the determination of the parameters) and the theoretical ones. The good concordance between the experimental and calculated conversion values confirmed that the design model can be used to predict the transient behaviour of the reactor.
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    Assessment and statistical modelling of airborne microorganisms in Madrid
    (Elsevier, 2020-11-21) Cordero, José María; Núñez, Andrés; García, Ana M.; Borge, Rafael; Genética y Microbiología
    The limited evidence available suggests that the interaction between chemical pollutants and biological particles may intensify respiratory diseases caused by air pollution in urban areas. Unlike air pollutants, which are routinely measured, records of biotic component are scarce. While pollen concentrations are daily surveyed in most cities, data related to airborne bacteria or fungi are not usually available. This work presents the first effort to understand atmospheric pollution integrating both biotic and abiotic agents, trying to identify relationships among the Proteobacteria, Actinobacteria and Ascomycota phyla with palynological, meteorological and air quality variables using all biological historical records available in the Madrid Greater Region. The tools employed involve statistical hypothesis contrast tests such as Kruskal-Wallis and machine learning algorithms. A cluster analysis was performed to analyse which abiotic variables were able to separate the biotic variables into groups. Significant relationships were found for temperature and relative humidity. In addition, the relative abundance of the biological phyla studied was affected by PM10 and O3 ambient concentration. Preliminary Generalized Additive Models (GAMs) to predict the biotic relative abundances based on these atmospheric variables were developed. The results (r = 0.70) were acceptable taking into account the scarcity of the available data. These models can be used as an indication of the biotic composition when no measurements are available. They are also a good starting point to continue working in the development of more accurate models and to investigate causal relationships.
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    Commissioning of the Controlled and Automatized Testing Facility for Human Behavior and Control (CASITA)
    (MDPI, 2018-08-27) Rodríguez Rodríguez, Ignacio; González Vidal, Aurora; Ramallo González, Alfonso Pablo; Zamora Izquierdo, Miguel Ángel; Ingeniería de la Información y las Comunicaciones; Facultades de la UMU::Facultad de Informática
    Human behavior is one of the most challenging aspects in the understanding of building physics. The need to evaluate it requires controlled environments and facilities in which researchers can test their methods. In this paper, we present the commissioning of the Controlled and Automatized Testing Facility for Human Behavior (CASITA). This is a controlled space emulation of an office or flat, with more than 20 environmental sensors, 5 electrical meters, and 10 actuators. Our contribution shown in this paper is the development of an infrastructure-Artificial Intelligence (AI) model pair that is perfectly integrated for the study of a variety of human energy use aspects. This facility will help to perform studies about human behavior in a controlled space. To verify this, we have tested this emulation for 60 days, in which equipment was turned on and off, the settings of the conditioning system were modified remotely, and lighting operation was similar to that in real behaviors. This period of commissioning generated 74.4 GB of raw data including high-frequency measurements. This work has shown that CASITA performs beyond expectations and that sensors and actuators could enable research on a variety of disciplines related to building physics and human behavior. Also, we have tested the PROPHET software, which was previously used in other disciplines and found that it could be an excellent complement to CASITA for experiments that require the prediction of several pertinent variables in a given study. Our contribution has also been to proof that this package is an ideal “soft” addition to the infrastructure. A case study forecasting energy consumption has been performed, concluding that the facility and the software PROPHET have a great potential for research and an outstanding accuracy.
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    Modelling of photosynthesis, respiration and nutrients yield coefficients in Scenedemus almeriensis culture as a function of nitrogen and phosphorus.
    (2021-09-14) Gómez serrano, Cintia; Acién Fernández, Francisco Gabriel; Fernández Sevilla, José María; Molina Grima, Emilio; Sánchez Zurano, Ana; Ingeniería Química
    Se aplicaron técnicas foto-respirométricas para evaluar la actividad fotosintética en organismos fototróficos. Estos métodos permiten analizar la respuesta fotosintética bajo diferentes condiciones. En este trabajo, se estudió la influencia de la disponibilidad de nutrientes (nitrato, amonio y fosfato) en la fotosíntesis y la respiración de Scenedesmus almeriensis mediante mediciones foto-respirométricas cortas. Tanto la fotosíntesis como la respiración aumentaron hasta un valor de saturación y posteriormente disminuyeron, mostrando inhibición a concentraciones altas. En cuanto a la influencia de la concentración de fósforo en las células de microalgas, se observó una tendencia hiperbólica similar, aunque no se detectó inhibición a concentraciones elevadas. A partir de estos datos experimentales, las tasas de respiración y fotosíntesis de S. almeriensis se modelaron utilizando la ecuación de Haldane para los datos de nitrato y amonio, y la ecuación de Monod para los datos de fosfato. Además, se realizaron experimentos para determinar los coeficientes de rendimiento de nitrógeno y fósforo en los cultivos de S. almeriensis. Los resultados mostraron que estos coeficientes no son constantes y se modifican según la concentración de nutrientes, evidenciando el fenómeno de absorción de lujo. Finalmente, los modelos propuestos se incorporaron en una herramienta de simulación para evaluar la actividad fotosintética y los coeficientes de rendimiento de nutrientes de S. almeriensis cuando se utilizan diferentes medios de cultivo y aguas residuales como fuente de nitrógeno y fósforo para su crecimiento.