Extinción de una llama de premezcla en canales estrechos con y sin recirculación de calor

El avance experimentado en los últimos años en campos como las técnicas de fabricación y los materiales ha hecho que se abran barreras y surjan nuevas oportunidades en el mundo de la micro-generación de potencia. Este es un campo muy novedoso en el que la mayoría de sus aplicaciones se encuentran aún en la fase de viabilidad. A modo de introducción, en este proyecto se explica de dónde surge la necesidad de tener sistemas productores de potencia en muy pequeña escala, incluyendo una pequeña descripción de las cuestiones fluidotérmicas, físicas y químicas que lleva consigo implícita la reducción en la escala, donde el comportamiento difiere considerablemente en comparación con sistemas más grandes. Dentro de esta introducción estarán incluidas algunas de las posibles aplicaciones que puede tener la generación de potencia en pequeña escala. Después de la introducción, este proyecto se centrará en estudiar cómo afecta la reducción en la escala a la combustión en canales estrechos. Primero se estudiará el efecto que provocan las pérdidas de calor a través de las paredes en los límites de flamabilidad en un canal donde se permite la transferencia de calor al exterior por una de sus paredes, observando que incluso bajas pérdidas de calor llegan a producir la extinción completa de la llama según se reduce la longitud característica. Después basándose en el combustor Swiss-roll desarrollado por primera vez por Lloyd y Weinberg [Ref. 3] se contrarrestarán estas pérdidas de calor circulando un gas en contracorriente de manera que precaliente la mezcla fría a la entrada, provocando una disminución notable en las pérdidas de calor. Para realizar este estudio se utilizará un modelo simplificado y no se pretende analizar de manera exhaustiva la dinámica de la combustión, que resulta ser muy compleja, sino determinar los parámetros que afectan en mayor medida a la existencia de una llama en un canal estrecho y qué circunstancias la pueden llevar a su extinción. Se comprobará que existen valores limitantes en la escala a partir de los cuales la combustión no se puede sostener, incluso incrementando la entalpía de la mezcla entrante por medio de la recirculación de calor como se mencionaba antes. A pesar de que siempre existirá un límite en la escala, se verá que gracias a este método se alcanzan temperaturas superiores a la temperatura adiabática de llama y que se logra mantener la combustión para escalas mucho menores que en un solo canal sin recirculación. Para la realización del estudio se ha desarrollado un código en lenguaje Fortran donde se resuelven de forma numérica las ecuaciones que rigen una llama pobre de premezcla. Se empieza resolviendo el caso más sencillo, que es un solo canal con pérdidas, donde se analizan los efectos que producen las pérdidas de calor a través de las paredes conjuntamente con la reducción en la escala a la existencia de la llama. Posteriormente se resuelve el caso donde un gas que circula en contracorriente calienta la mezcla entrante y se analiza en función de distintos parámetros geométricos y fluidotérmicos la existencia de llama según se reduce la escala, hasta llegar a la extinción completa. Este análisis se realiza mediante un método de continuación. Finalmente se comparan ambos casos y se concluye que la recirculación de calor extiende en gran parte la existencia de combustión cuando se reduce la escala del problema. Por último, con el objetivo de optimizar el tiempo de cálculo y el coste computacional, en el apéndice se propone realizar una transformación de coordenadas, donde se aumenta la resolución en los alrededores de la llama.Ingeniería Industria

Business plan: Litux

Treball Final de Grau en Administració d'Empreses. Codi: AE1049. Curs 2020/2021Litux, is a web project for the promotion of premises, whose function is that users can consult and visit the places that best suit them. The objective of Litux is the promotion of bars, pubs, restaurants, discos, exchange clubs and singles clubs. As a result of this promotion, it is intended to classify the different places according to the public that visits them, in order to create stable and sociable climates. We want to offer a reservation management, promotion and customer loyalty service apart from transmitting a greater number of information to users so that they can choose the most suitable location for them, be it the average age of the customers or the average price between others. Our target audience is any owner of a local who is willing to promote himself and any user who is looking for a specific place to socialize. We must highlight as competitors those promotion websites or dating websites. What differentiates us from them is the amount of extra data we provide in reference to the public and the creation of an environment to socialize. In reference to the web page sector, it is a very mature sector, with a large number of competitors which leads us to an oligarchy. Based on the different analyzes carried out on the competitors and the environment, we have decided to take the following competitive and marketing strategies: Cost leadership, Low cost differentiation, focus strategy and “push” strategy. Initially, the company is consolidated by two working partners, who delegate certain tasks to external companies. The transmission and promotion of the service will be carried out personally by visiting certain venues or participating in certain events. With the growth of the company, it is intended to expand the workforce and that the tasks carried out by external companies are carried out by the staff themselves. In the same way, it is intended that clients look for our website to promote themselves and not us look for them (Change of strategy from "push" to "pull"). We intend to bill each client a different price depending on the category he chooses, the cheapest being € 30 per month. Being a new company, it requires a certain amount of money and a large amount of work. For this reason, we have estimated that we will need a bank loan of € 8,000 and the first year will cost us € 22,870. We have also calculated that the company will begin to be profitable from customer No. 60. We believe that Litux is a viable project, due to the change in today's society and by transmitting the amount of information necessary for users to feel safe and comfortable in their decisions without having to make prior visits to the premises. The first years will be negative and hard due to the total outlay involved in the creation of the company, but these results will be validated from the second year. With the obtaining of positive results, we will be able to consider the expansion of the company and the hiring of more people

Análisis de la transformación de los modelos de negocio periodísticos: propuesta de un nuevo framework para estudios de caso

La industria periodística ha mostrado dificultades para encontrar modelos de negocio sostenibles en el contexto digital. De acuerdo con la literatura científica del campo de la empresa, un modelo de negocio está formado por una serie de componentes cuyas interacciones describen la lógica con que una compañía crea, distribuye y captura valor. Sin embargo, la investigación centrada en la economía de los medios de comunicación se ha centrado en buscar nuevas fuentes de ingresos para el sector. Por esta razón, adolece una falta de visiones holísticas sobre el modelo de negocio que, además, tengan en cuenta la importancia de la creación de valor como elemento nuclear de cualquier estrategia empresarial. Para contribuir a la resolución de este problema, la presente investigación propone una herramienta metodológica que permita analizar, de forma completa y con atención a los procesos relacionados con la creación de valor, un modelo de negocio periodístico. La metodología se basa en un cuestionario (n=16) a expertos en modelos de negocio de empresas informativas y ofrece como resultado un framework para estudios de caso compuesto por una ficha de la empresa, preguntas de investigación para seis componentes del modelo de negocio y preguntas de investigación para desarrollar un análisis crítico sobre los vínculos, las interacciones y las sinergias entre esos elementos.The journalism industry is struggling to create sustainable business models for the digital age. Prior research in the field of media economics has broadly analyzed this challenge through case studies. According to extant research on management, a business model is comprised by components whose interactions convey the logic of creating, distributing and capturing the value developed by a firm. However, many journalism scholars have focused on new revenue streams, and not only is there a lack of holistic views, but value must be considered when applying the business model concept. In response to the aforementioned problem, this paper proposes a methodological tool that future researchers may use to analyze the business model of any news company. The method is based on a questionnaire (n=16) submitted to experts specialized in media business models, and the paper proposes a global framework aimed at improving comparisons between companies and gaining a better understanding of the success patterns for sustainable business models in order to foster innovation and knowledge transfer. This framework consists of a case file, research questions for six components of the business models, and re-search questions for a critical assessment of the links, interactions and synergies between them

Theoretical Spectrscopic Study of Two Ketones of Atmospheric Interest: Methyl Glyoxal (CH3COCHO) and Methyl Vinyl Ketone (CH3COCH=CH2)

Two ketones of atmospheric interest, methyl glyoxal and methyl vinyl ketone, are studied using explicitly correlated coupled cluster theory and core−valence correlationconsistent basis sets. The work focuses on the far-infrared region. At the employed level of theory, the rotational constants can be determined to within a few megahertz of the experimental data. Both molecules present two conformers, trans/cis and antiperiplanar (Ap)/ synperiplanar (Sp), respectively. trans-Methyl glyoxal and Ap-methyl vinyl ketone are the preferred structures. cis-Methyl glyoxal is a secondary minimum of very low stability, which justifies the unavailability of experimental data in this form. In methyl vinyl ketone, the two conformers are almost isoenergetic, but the interconversion implies a relatively high torsional barrier of 1798 cm−1. A very low methyl torsional barrier was estimated for trans-methyl glyoxal (V3 = 273.6 cm−1). Barriers of 429.6 and 380.7 cm−1 were computed for Ap- and Sp-methyl vinyl ketone. Vibrational second-order perturbation theory was applied to determine the rovibrational parameters. The far-infrared region was explored using a variational procedure of reduced dimensionality. For trans-methyl glyoxal, the ground vibrational state was estimated to split by 0.067 cm−1, and the two low excited energy levels (1 0) and (0 1) were found to lie at 89.588 cm−1/88.683 cm−1 (A2/E) and 124.636 cm−1/123.785 cm−1 (A2/E). For Ap- and Sp-methyl vinyl ketone, the ground vibrational state splittings were estimated to be 0.008 and 0.017 cm−1, respectively.European Commission 872081National Plan for Science, Technology and Innovation (MAARIFAH), King Abdulaziz City for Science and Technology, Kingdom of Saudi Arabia 0061-00101-17-2Spanish Government EIN2019-103072 PID2020112887GB-I00 PID2019-104002GB-C21ERDF A Way of Making Europe European Union Next Generation EU/PRTRCTI (CSIC)CESGARed Espanola de Computacion AECT-20202-0008 RES-AECT-2020-3-001

Configuration localized Morse wave functions: Application to vibrational transitions in anharmonic diatomic molecules

The bound states of a Morse potential are described in terms of a basis of states that are characterized for being eigenstates of the Morse variable. These states are strongly localized in configuration space; thus they are called configuration localized Morse (CLM) wave functions. These are shown to provide a powerful tool to calculate analytically, to a good approximation, matrix elements of arbitrary functions of the interatomic separation between vibrational states of anharmonic diatomic molecules. Applications of CLM wave functions to the calculation of vibrational transitions in HF and DF diatomic molecules are presented.Dirección General de Investigación Científica y Técnica PB95-0533European Commission CI1*-CT94-007

Studies of the early medieval pottery of Al-Andalus

Se adjunta el archivo de las pruebas de imprenta. "The definitive version is available at www.blackwell-synergy.com"This paper presents a review of the studies of early medieval (Amiral and Caliphal) pottery in al-Andalus. It opens with a discussion of the first archaeological and ceramics surveys, including an assessment of their historical and theoretical contexts and their relevance to the developing discipline. After discussion of the contributions and also shortcomings of current approaches, the article closes by sketching the direction of future research

Analytic evaluation of Franck-Condon integrals for anharmonic vibrational wave functions

The problem of calculating Franck-Condon overlap integrals in molecular transitions between vibrational states in different electronic configurations is addressed. An exact and easily applicable analytical expression is obtained when the vibrational states can be approximated by eigenstates of Morse potentials with different strengths and locations but identical ranges. An approximate analytical expression is obtained for the general case. The method is applied to the stretching S-S mode corresponding to [Formula Presented] transitions in the [Formula Presented] molecule.Dirección General de Investigación Científica y Técnica PB95-053

¿Estaba Bolivia inmunizada para evitar el contagio de la crisis financiera internacional?

35 p.La crisis financiera y económica de 2008 tuvo múltiples consecuencias, trastocó el desempeño de las economías y puso en duda paradigmas que habían orientado la política económica en la mayoría de los países. No obstante, la situación en Bolivia fue diferente, como resultado de los altos precios de las materias primas y la escasa vinculación al sistema financiero internacional, permitió que la economía boliviana estuviera inmunizada al contagio de la crisis internacional. Sin embargo, las acciones del gobierno de sustentar el crecimiento de la economía en el gasto público encubo una nueva enfermedad, manifestándose en los años venideros a las crisis.The financial and economic crisis of 2008 had multiple consequences, disrupting the performance of the economies and questioning paradigms that had guided economic policy in most countries. However, the situation in Bolivia was different, as a result of the high prices of raw materials and the poor connection to the international financial system, allowed the Bolivian economy to be immunized from contagion from the international crisis. However, the government's actions to support the growth of the economy in public spending concealed a new disease, manifesting itself in the coming years to the crises

Isocyanic acid (HNCO) in the hot molecular core G331.512-0.103: observations and chemical modelling

The authors thank the anonymous referee for the useful comments that improved the article. CMC acknowledges the support of CNPq, Conselho Nacional de Desenvolvimento Cientifico e Tecnologico Brazil, process number 141714/2016-6. This study was financed in part by the Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior - Brasil (CAPES) - Finance Code 001. LB acknowledges support fromCONICYT (Comision Nacional de Investigacion Cientifica y Tecnologica) project Basal AFB-170002. EM acknowledges support from the Brazilian agencies FAPESP (Fundacao de Amparo a Pesquisa do Estado de Sao Paulo, grant 2014/22095-6) and CNPq (grant 150465/2019-0). MC acknowledges the financial support from theEuropean Union'sHorizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement no 872081; from the Spanish National Research, Development, and Innovation plan (RDI plan) under the project PID2019-104002GB-C21; the Consejeria de Conocimiento, Investigacion y Universidad, Junta de Andalucia and European Regional Development Fund (ERDF), ref. SOMM17/6105/UGR; the Ministerio de Ciencia, Innovacion y Universidades (ref. COOPB20364); and by the Centro de Estudios Avanzados en Fisica, Matematicas y Computacion (CEAFMC) of the University of Huelva.Isocyanic acid (HNCO) is a simple molecule with a potential to form prebiotic and complex organic species. Using a spectral survey collected with the Atacama Pathfinder EXperiment, in this work we report the detection of 42 transitions of HNCO in the hot molecular core/outflow G331.512-0.103 (hereafter G331). The spectral lines were observed in the frequency interval ∼160–355 GHz. By means of Local Thermodynamic Equilibrium analyses, applying the rotational diagram method, we studied the excitation conditions of HNCO. The excitation temperature and column density are estimated to be Tex= 58.8 ± 2.7 K and N = (3.7 ± 0.5) × 1015 cm−2, considering beam dilution effects. The derived relative abundance is between (3.8 ± 0.5) × 10−9 and (1.4 ± 0.2) × 10−8. In comparison with other hot molecular cores, our column densities and abundances are in agreement. An update of the internal partition functions of the four CHNO isomers: HNCO; cyanic acid, HOCN; fulminic acid, HCNO; and isofulminic acid, HONC is provided. We also used the astrochemical code NAUTILUS to model and discuss HNCO abundances. The simulations could reproduce the abundances with a simple zero-dimensional model at a temperature of 60 K and for a chemical age of ∼105 yr, which is larger than the estimated dynamical age for G331. This result could suggest the need for a more robust model and even the revision of chemical reactions associated with HNCO.Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPQ) 141714/2016-6Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES) 001Comision Nacional de Investigacion Cientifica y Tecnologica (CONICYT) Basal AFB-170002Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) 2014/22095-6Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPQ) 150465/2019-0European Union'sHorizon 2020 research and innovation program under the Marie Sklodowska-Curie grant 872081Spanish National Research, Development, and Innovation plan (RDI plan) PID2019-104002GB-C21Consejeria de Conocimiento, Investigacion y UniversidadJunta de AndaluciaEuropean Commission SOMM17/6105/UGRMinisterio de Ciencia, Innovacion y Universidades COOPB20364Centro de Estudios Avanzados en Fisica, Matematicas y Computacion (CEAFMC) of the University of Huelv