Universidad Tecnológica de Bolívar
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Unidimensional and 3D Analyses of a Radial Inflow Turbine for an Organic Rankine Cycle under Design and Off-Design Conditions
No full textThe organic Rankine cycle (ORC) is an efficient technology for electricity generation from
low- and medium-temperature heat sources. In this type of power cycle, the radial inflow turbine
is the option usually selected for electricity generation. As a critical ORC component, turbine
performance markedly affects the efficiency of the system. Therefore, the challenge is to model the
behavior of the radial inflow turbine operating with organic fluids for heat recovery applications.
In this context, various groups of fluids are highlighted in the scientific literature, including R-123,
R-245fa, and R-141b, which are the fluids used in this research. Since little research has focused on
the turbine efficiency effect on the power cycle design and analysis, this study presents an analysis of
a radial inflow turbine based on a mathematical model of a one-dimensional design of the turbine.
From this analysis, geometric, thermal, and operating parameters were determined, as well as volute,
stator, and rotor losses. For this purpose, an algorithm was implemented in MATLAB to calculate
the one-dimensional parameters of the turbine. Using these parameters, a 3D model of the turbine
was designed in ANSYS-CFX, with performance curves of each projected turbine under design and
off-design conditions. The numerical results suggest that the isentropic efficiency of all the proposed
turbines under design conditions can surpass 75%. Additionally, the findings indicate that different
design conditions, such as specific speed, pressure ratio, and turbine size, can affect the efficiency of
radial inflow turbines in ORC systems
Does News Platform Matter? Comparing Online Journalistic Role Performance to Newspaper, Radio, and Television
No full textThe shifting role of journalism in a digital age has affected long-standing journalistic norms across media platforms. This has reinvigorated discussion on how work in online newsrooms compares to other platforms that differ in media affordances and forms. Still, more studies are needed on whether those differences translate into distinct practices, especially when examining cross-national studies. Based on a content analysis of 148,474 stories produced by 365 media organizations from 37 countries, this article compares the performance of journalistic roles in online newsrooms to three other types of media—TV, radio, and print. The paper analyzes if journalistic roles present themselves differently across platforms, and if these differences are constant or they vary across countries. Results show that there are measurable differences in role performance in online journalism compared to other platforms. Platform had a significant impact, particularly in terms of service and infotainment orientation, while the implementation of roles oriented toward public service was more similar. Additionally, country differences in the relationship between role performance and platforms mainly emerged for roles that enable political influence on news coverage, with differences in the relationship between online vs. traditional platforms appearing to be distinct features of the specific political system. © 2023 Informa UK Limited, trading as Taylor & Francis Group
Diagnóstico de las organizaciones solidarias del sector artístico-cultural en Córdoba y Sucre
No full textThis study from the creative and solidarity economy industries, aimed to diagnose the artistic-cultural solidarity organizations in the Colombia´s department Córdoba and Sucre, by reviewing external and internal factors, to expand possible channels in their development; the assisted questionnaires validated by Artesanías de Colombia and the business solidarity entities of Alfaro (2017) were applied in 103 entities. In the results of the diagnostic matrix, external factors had a score of 2.9 and internal factors 2.56; indicating that they are below the average level of cultural industries. In the synthesis of strategic factors the result was 3.0, within the average of the cultural industry; internally, the plurality and ethnic diversity in the composition of the associates, high creativity and medium expertise stand out. The main findings for the external, allow to recommend in the short term to participate in the integral program of rural cooperative solidarity intervention, participation in tourism from the cultural and heritage perspective promoting creative vocations. Future research should be considered from the development of capacities in innovation and sustainable intelligence. © 2020, Universidad del Zulia. All rights reserved
Love Thy Neighbor: La Vida Musical De Justo Almario
No full textEl viejo Rafa, en palabras de Justo, se esmeró en que él estudiara y aprovechara el tiempo (Rodríguez Osorio 1994a, vol. 1, sec. 0:45-0:50). El estudio y práctica de la música eran entonces centrales en su formación. Todos los testimonios que Justo da sobre esa época en Barranquilla están relacionados con su práctica y aprendizaje de la música en compañía de Jorge Rafael, momentos descritos con gran afecto y agradecimiento
Sí, el viejo tenía en el patio de la casa muchos árboles: árboles de anón, árboles de matarratón, guanábana, guayaba… tenía también yerbabuena, entonces nos levantábamos temprano, como a las cinco de la mañana y lo que hacíamos era regar el jardín. Al frente de la casa había una grama, la casa estaba como así a esta altura que tenía unos andenes que bajaban, entonces a cada lado de la casa había grama, entonces veníamos y regábamos, entonces él siempre usaba como filosofía para inspirarme a que lo ayudar a regar el jardín a comparar la vida con un jardín, y también la música. Me acuerdo que decía que “la música es un jardín de arte y ciencia entre el deleite y el ritmo universal”, algo así me decía él, entonces todo eso siempre se quedó conmigo. Y me acuerdo que después que regábamos el jardín, hacíamos desayuno, y en ese momento después del desayuno sacaba el flautín: “ok, Justico, saca el flautín, aquí viene la lección”, así, en el patio, bajo el palo de anón: “tu, tu, tu, tu, tu [tararea ejercicios de escalas]”, así como hasta las 8 de la mañana. “Bueno, pal colegio ahora” [decía]
Skin color correction via convolutional neural networks in 3D fringe projection profilometry
No full textFringe Projection Profilometry (FPP) with Digital Light Projector technology is one of the most reliable 3D sensing techniques for biomedical applications. However, besides the fringe pattern images,often a color texture image is needed for an accurate medical documentation. This image may be acquired either by projecting a white image or a black image and relying on ambient light. Color Constancy is essential for a faithful digital record, although the optical properties of biological tissue make color reproducibility challenging. Furthermore, color perception is highly dependent on the illuminant. Here, we describe a deep learning-based method for skin color correction in FPP. We trained a convolutional neural network using a skin tone color palette acquired under different illumination conditions to learn the mapping relationship between the input color image and its counterpart in the sRGB color space. Preliminary experimental results demonstrate the potential for this approach
Representación de la historia de españa por medio de la filatelia. Estudio de los sellos diseñados por gallego y rey
No full textThe research presents a detailed analysis of all Spanish postage stamps created by the humorists Gallego and Rey, which intended to reflect the Spanish history. This peculiar kind of philatelic product, based on the combination of historical facts and caricatures, had as initial objective to encourage mailing among young people resulting in an exhibition of a sole vision of the Spanish history. Through a review of the entire series of stamps entitled “History of Spain” (2000-2017) all the content of these communicative and pedagogical elements was studied. The most relevant results of this study allowed us to determine that the authors presented some ideological bias, concluding that this philatelic material transmitted a series of values that highlighted historical events linked to Spanish nationalismSe presenta un análisis pormenorizado de todos los sellos postales españoles elaborados por los humoristas gráficos Gallego y Rey, los cuales pretendieron reflejar la historia española. Este peculiar tipo de producto filatélico, basado en la combinación de hechos históricos y caricaturas, tuvo como objetivo inicial el de fomentar la correspondencia entre los jóvenes lográndose formar un conjunto que exhibe una visión de toda la historia española. Por medio de una revisión de toda la serie de sellos titulada “Historia de España” (2000-2017) se estudió todo el contenido de estos elementos comunicativos y pedagógicos. Los resultados más relevantes nos permitieron determinar que los autores presentaron ciertos sesgos ideológicos, concluyendo que este material filatélico transmitió una serie de valores que ensalzaban hechos históricos ligados al nacionalismo español
Student Entrepreneurship and Innovation Competition
No full textConsuming food with high nutritional value, reducing the negative impacts that indiscriminate cultivation causes in nature, and the low competitiveness of farming families against agricultural industries, are issues that Colombian society face nowadays. VEGY is an App that amid to act as a direct bridge between farming families and buyers who want to obtain their crops or rent a piece of land to harvest. The App also offers complete information about the agricultural product; location, planting day, harvesting and storage. We categorize in the service sector, particularly the sector of buying and selling agricultural food; vegetables, fruits, tubers, etc. Finally, the profile of our customers ranges between the ages of 18 and 45 years, who may be owners of medium and small businesses belonging to the food sector; food restaurants, community stores, farmers markets, etc., not forgetting family households passionate about environmental, technological and social issues
Agro-Industrial Waste from Cocoa Pod Husk (Theobroma cacao L.), as a Potential Raw Material for Preparation of Cellulose Nanocrystals
No full textObtaining cellulose from agro-industrial waste offers the possibility of generating added value to solid biomass that is currently deposited in sanitary landfills. This research performed the evaluation of a residue from cocoa husk pods (Theobroma cacao L.), from the agricultural industry. The cellulose fiber was obtained through chemical treatments with KOH at 5% w/v to remove non-cellulosic components and then the fiber was bleached with 3% v/v hydrogen peroxide. The changes in chemical structure were determined through Fourier transform infrared spectroscopy (FTIR). The FTIR analysis confirms the progressive decrease of lignin and hemicellulose after applying chemical treatment. The morphological changes in the surface of the fiber were characterized using the SEM technique. The mass percentage of cellulose increases up to 68 %. It is expected that the Nano Crystals (NCC) extracted from the biomass of the cocoa husk pods, present a high index of crystallinity and that they are also in suitable conditions to be useful as reinforcing agents in polymeric or mineral matrices, and may have potential application for technology transfer
Mudanças no jornalismo e seu impacto na autonomia profissional: evidência do estudo The Worlds of Journalism em sete países da América Latina
No full textLos debates en torno al futuro del periodismo posibilitaron numerosas investigaciones sobre sus cambios en el nuevo contexto hiperdigitalizado. Sin embargo, se desconoce su impacto en la libertad de prensa, específicamente en la autonomía editorial. Con datos del último The Worlds of Journalism Study 2012-2016, este artículo explora la percepción de 2789 periodistas de Argentina, Brasil, Chile, Colombia, Ecuador, El Salvador y México sobre este fenómeno. Mediante la aplicación de un análisis de covarianza SEM, se identificaron cinco factores de cambio percibidos por estos profesionales: la comunicación digital interactiva, la certificación profesional, las consideraciones formativas o normativas, la importancia social del periodismo y las presiones económicas. Respecto de la forma en la que operan estos cambios, la autonomía aumenta cuando se fortalece la percepción sobre la relevancia social del periodismo y el tiempo para investigar y disminuye cuando aumentan las presiones lucrativas. Los hallazgos reafirman la importancia de no perder de vista los valores o cualidades centrales del periodismo, como la autonomía, la responsabilidad social y el profesionalismo que deben mantenerse en estos tiempos de fuertes cambios mediados por las nuevas tecnologías de la información y de las comunicaciones.The debates on the future of journalism have led to a great deal of research
on its changes in the new hyper-digitalized context. However, its impact on press freedom,
specifically on editorial autonomy, is unknown. Using data from the last The Worlds of
Journalism Study (2012-2016), this article explores the perception of 2,789 journalists
in Argentina, Brazil, Chile, Colombia, Chile, Ecuador, El Salvador, and Mexico on this
phenomena. Applying SEM covariance analysis, we identified five factors of change perceived
by these professionals: interactive digital communication, professional certification, the social
importance of journalism, economic pressures, and training and regulatory considerations.
We found that autonomy increases when the perception of the social relevance of journalism
and time for research is strengthened and decreases when lucrative pressures increase. The
results reaffirm the importance of not losing sight of the core values or qualities of journalism,
such as autonomy, social responsibility, and professionalism, which must be maintained in
these times of strong changes mediated by new information and communications technologiesOs debates sobre o futuro do jornalismo levaram a muitas pesquisas sobre
suas mudanças no novo contexto de hiper digitalização. No entanto, seu impacto
na liberdade de imprensa, especialmente na autonomia editorial, é desconhecido.
Utilizando dados do último The Worlds of Journalism Study (2012-2016), este artigo
explora a influência de 2789 jornalistas da Argentina, do Brasil, da Colômbia, do
Chile, do Equador, de El Salvador e do México. Aplicando a análise de covariância
SEM, foram identificados cinco fatores de mudança percebidos por estes profissionais:
a comunicação digital interativa, a certificação profissional, as considerações
formativas ou normativas, a importância social do jornalismo, as pressões econômicas.
Em relação à forma em que operam essas mudanças, a autonomia aumenta quando
é fortalecida a percepçãosobre a relevância social do jornalismo e o tempo para
pesquisar, e diminui quando as pressões lucrativas aumentam. Os resultados
reafirmam a importância de não perder de vista os valores ou qualidades centrais
do jornalismo, como a autonomia, a responsabilidade social e o profissionalismo
que devem ser mantidos nesses tempos de fortes mudanças mediadas pelas novas
tecnologias da informação e das comunicações
A Software for Simulating Robot Swarm Aggregation
No full textSwarm robotics is a topic that focuses on studying a system composed of many homogeneous robots that collaborate to achieve a common goal. Swarm robotics presents several exciting challenges for engineers, with the development of controllers being one of the most critical. For this purpose, models and simulators have been developed to allow designers to test their designs. This paper presents a swarm robot simulator, made in Matlab, whose objective is to study robot aggregation, which is considered an essential swarm behavior. Simulations and results of a classical algorithm for environment-guided aggregation are presented to determine its ability to aggregate robots and how its efficiency is affected by environmental variations. © 2022, The Author(s), under exclusive license to Springer Nature Switzerland AG