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Chemical looping combustion (CLC) technology offers cost-effective CO2 emission reduction. Coal direct chemical looping (CDCL) emerges as a promising solid fuel CLC technology owing to its ability to directly utilize coal without prior gasification, enhancing system integration and efficiency. Despite significant progress in CDCL, challenges persist, including carbon deposition and insufficient oxidation and reduction of oxygen carriers (OCs). This study conducted a thermodynamic equilibrium analysis of a CDCL combustion reactor using Cantera 3.0, a chemical calculation module developed at the California Institute of Technology. The analysis explored the impact of different temperatures, OC-to-coal molar ratios (θ), and OCs types on combustion products. By employing the minimum Gibbs function method and analyzing intrinsic reaction mechanisms, the study provides insights for predicting and optimizing system performance. Thermodynamic equilibrium analysis revealed that with CuO as the OC, insufficient OC (θ < 0.6) led to Cu as the reduction product, while sufficient OC (0.6 < θ < 1.3) yielded Cu and CuO, and excess OC (θ > 1.3) resulted in Cu2O. To optimize CO2 capture, a molar ratio of θ of at least 1.4 and a temperature of at least 800°C are recommended. When Fe2O3 served as the OC, insufficient OC (θ < 0.45) produced Fe and FeO, while excess OC generated FeO and Fe3O4. Optimal operational performance and CO2 capture efficiency required an OC-to-coal molar ratio exceeding 1.4 and a temperature higher than 700°C. This study demonstrates that in CDCL combustion systems, selecting appropriate OCs, temperatures, and OC-to-coal molar ratios ensures stable and efficient combustion and CO2 capture. These findings offer crucial guidance for optimizing system operation. [ABSTRACT FROM AUTHOR]

Una de las peculiaridades de los espacios e infraestructuras subterráneas es el quedar ocultos dentro de grandes masas pétreas, sin un correlato masivo exterior. El límite entre espacio y masa es la propia superficie excavada donde percibimos la textura pétrea o terrena. En cuanto a su consideración patrimonial, son espacios creados en el terreno para cumplir un fin específico que complementa a las estructuras emergentes. Su construcción en muchos casos es sustractiva, una singularidad tipológica, que los sitúa a medio camino entre su calificación como edificios patrimoniales, como elementos infraestructurales o como yacimientos arqueológicos. Estas singularidades hacen que su representación, documentación y análisis gráfico sean complejos, y muchas veces infructuoso. Por ello este ­ofrecer estrategias y metodologías que contribuyan, a través de recursos gráficos digitales e impresiones 3d, a la correcta documentación, visualización de espacios con geometría irregular y compleja, con el objetivo de favorecer su análisis, conservación, difusión y puesta en valor.

In this paper, we explore the deflagration combustion of methane–air mixtures through both experimental and numerical analyses. The key parameters defining deflagration combustion dynamics include maximum explosion pressure (Pmax), maximum rate of explosion pressure rise (dP/dt)max, deflagration index (KG), and laminar burning velocity (SU). Understanding these parameters enhances the process of safety design across the energy sector, where light-emissive fuels play a crucial role in energy transformation. However, most knowledge on these parameters comes from experiments under standard conditions (P = 1 bar, T = 293.15 K), with limited data on light hydrocarbon fuels at elevated temperatures. Our study provides new insights into methane–air mixture deflagration dynamics at temperatures ranging from 293 to 348 K, addressing a gap in the current process industry knowledge, especially in gas and chemical engineering. We also conduct a comparative analysis of predictive models for the laminar burning velocity of methane mixtures in air, including the Manton, Lewis, and von Elbe, Bradley and Mitcheson, and Dahoe models, alongside various chemical kinetic mechanisms based on experimental findings. Notably, despite their simplicity, the Bradley and Dahoe models exhibit a satisfactory predictive accuracy when compared with numerical simulations from three chemical kinetic models using Cantera v. 3.0.0 code. The findings of this study enrich the fundamental combustion data for methane mixtures at elevated temperatures, vital for advancing research on natural gas as an efficient "bridge fuel" in energy transition. [ABSTRACT FROM AUTHOR]

This study investigates the Rankine vapor power thermodynamic cycle using steam/water as the working fluid, which is common in commercial power plants for power generation as the source of the rotary shaft power needed to drive electric generators. The four-process cycle version, which comprises a water pump section, a boiler/superheater section, a steam turbine section, and a condenser section, was considered. The performance of this thermodynamic power cycle depends on several design parameters. This study varied a single independent variable, the absolute pressure of the condenser, by a factor of 256, from 0.78125 to 200 kPa. The peak pressure and peak temperature in the cycle were fixed at 50 bar (5,000 kPa) and 600°C, respectively, corresponding to a base case with a base value for the condenser's absolute pressure of 12.5 kPa (0.125 bar). The analysis was performed using the thermodynamics software package Cantera as an extension of the Python programming language. The results suggest that over the range of condenser pressures examined, a logarithmic function can be deployed to describe the dependence of input heat, the net output work, and cycle efficiency on the absolute pressure of the condenser. Each of these three performance metrics decreases as the absolute pressure of the condenser increases. However, a power function is a better choice to describe how the steam dryness (steam quality) at the end of the turbine section increases as the absolute pressure of the condenser rises. [ABSTRACT FROM AUTHOR]

A rotating detonation engine (RDE) is a highly promising detonation-based propulsion system and has been widely researched in recent decades. In this study, BYCFoam, the latest gaseous version of the BYRFoam family, is developed specifically for RDE simulations. It is based on the standard compressible flow solver rhoCentralFoam in OpenFOAM and incorporates several enhancements: improved reconstruction variables and flux schemes; detailed chemistry and transport properties; the utilization of an adaptive mesh refinement (AMR) and dynamic load balancing (DLB). A series of comprehensive numerical tests are conducted, including the shock-tube problem, shock-wave diffraction, homogeneous ignition delay, premixed flame, planar detonation, detonation cellular structure and rotating detonation combustor (RDC). The results demonstrate that BYCFoam can accurately and efficiently simulate the deflagration and detonation processes. This solver enhances the capability of the BYRFoam family for the in-depth exploration of RDE in future research. [ABSTRACT FROM AUTHOR]

In a time when low emission solutions and technologies are of utmost importance regarding the sustainability of the aviation sector, this publication introduces a reduced-order physics-based model for combustion chambers of aeroengines, which is capable of reliably producing accurate pollutant emission and combustion efficiency estimations. The burner is subdivided into three volumes, with each represented by a single perfectly stirred reactor, thereby resulting in a simplified three-element serial chemical reactor network configuration, reducing complexity, and promoting the generality and ease of use of the model, without requiring the proprietary engine information needed by other such models. A tuning method is proposed to circumvent the limitations of its simplified configuration and the lack of detailed geometric data for combustors in literature. In contrast to most similar frameworks, this also provides the model with the ability to simultaneously predict the combustion efficiency and all pollutant emissions of interest ( N O x , C O and unburnt hydrocarbons) more effectively by means of implementing a detailed chemical kinetics model. Validation against three correlation methods and actual aeroengine configurations demonstrates accurate performance and emission trend predictions. Integrated within two distinct combustion chamber low-emission preliminary design processes, the proposed model evaluates each new design, thereby displaying the ability to be employed in terms of optimizing a combustor's overall performance given its sensitivity to geometric changes. Overall, the proposed model proves its worth as a reliable and valuable tool for use towards a greener future in aviation. [ABSTRACT FROM AUTHOR]

Accidental explosions of flammable gases are risky for lives and properties, especially if such an explosion occurs within a confined space, because internal pressure builds up within the enclosure. Having a deep understanding of these explosions and their consequences will enhance developing mitigation strategies to prevent future explosions and reduce the impact of their consequences. Explosion venting is a conventional method to mitigate the consequences of explosions in enclosures, with the computational explosion vent analyzer (EVA) being a tool used for predicting both the peak and transient pressures generated from accidental gaseous explosions. While the EVA has been employed to gaseous one-compound fuels so far, exploding multi-compound fuel mixtures are usually dealt with in practice. Hence, there has been a critical need to extend the capabilities of the EVA to account for fuel-blend explosions. This is performed in the present work, incorporating the Cantera software into the EVA platform to compute the laminar flame speeds for various fuel blends. As a result, a model predicting both the peak and transient pressures in an explosion of gaseous fuel blends is developed. Such a modification of the EVA entailed simulating explosions of hydrogen and hydrocarbons as well as hydrocarbon fuel blends of various compositions in vented and closed enclosures, along with its validation through experimental measurements. The study further investigated the effect of various parameters on the predicted transient and peak pressures, and the simulation results can be used in the design of safety vents for confined spaces. For explosion of a hydrogen-methane-air mixture, the model works better when the fuel mixture has higher vol% of hydrogen and predicts the peak pressure more accurately at larger vent areas. [ABSTRACT FROM AUTHOR]

El trabajo que se presenta en este artículo trata sobre el desarrollo de productos en material de cantera. Desde la perspectiva social del diseño, se busca una innovación sistémica, donde los saberes tradicionales de una comunidad como el Ejido de Escalerillas, en el estado de San Luis Potosí, México, son el referente para reflexionar sobre los cambios esperados en la localidad. El proceso del proyecto consideró, como parte del sistema, a tres ejes de indagación: lo productivo, lo social y lo comercial. A partir del reconocimiento de esos aspectos, se hicieron las siguientes preguntas: ¿Es necesaria una adecuación o cambio en sus procesos productivos? ¿Qué debería permanecer o quizá movilizarse de manera más pausada en los aspectos sociales? ¿Qué dirección debían tomar los cambios comerciales? Esto se hizo con el fin de poder generar propuestas de diseño comprometidas con la trayectoria cultural del grupo. El resultado fue, por un lado, una línea de productos utilitarios de pequeñas dimensiones en cantera como principal material y con un alto valor simbólico. Además, emergieron otros proyectos de carácter interdisciplinar, colaborativo y de investigación, donde la comunidad del Ejido y la institución educativa han mantenido doce años de intercambio permanente. Este artículo se centra en las bases que dieron inicio al proyecto.

In this paper, we explore the deflagration combustion of methane–air mixtures through both experimental and numerical analyses. The key parameters defining deflagration combustion dynamics include maximum explosion pressure (Pmax), maximum rate of explosion pressure rise (dP/dt)max, deflagration index (KG), and laminar burning velocity (SU). Understanding these parameters enhances the process of safety design across the energy sector, where light-emissive fuels play a crucial role in energy transformation. However, most knowledge on these parameters comes from experiments under standard conditions (P = 1 bar, T = 293.15 K), with limited data on light hydrocarbon fuels at elevated temperatures. Our study provides new insights into methane–air mixture deflagration dynamics at temperatures ranging from 293 to 348 K, addressing a gap in the current process industry knowledge, especially in gas and chemical engineering. We also conduct a comparative analysis of predictive models for the laminar burning velocity of methane mixtures in air, including the Manton, Lewis, and von Elbe, Bradley and Mitcheson, and Dahoe models, alongside various chemical kinetic mechanisms based on experimental findings. Notably, despite their simplicity, the Bradley and Dahoe models exhibit a satisfactory predictive accuracy when compared with numerical simulations from three chemical kinetic models using Cantera v. 3.0.0 code. The findings of this study enrich the fundamental combustion data for methane mixtures at elevated temperatures, vital for advancing research on natural gas as an efficient “bridge fuel” in energy transition.

The Adiabatic Flame Temperature (AFT) in combustion represents the maximum attainable temperature at which the chemical energy in the reactant fuel is converted into sensible heat in combustion products without heat loss. AFT depends on the fuel, oxidizer, and chemical composition of the products. Computing AFT requires solving either a nonlinear equation or a larger minimization problem. This study obtained the AFTs for oxy-methane (methane and oxygen), oxy-hydrogen (hydrogen and oxygen), air-methane (methane and air), and air-hydrogen (hydrogen and air) for stoichiometric conditions. The reactant temperature was 298.15 K (25°C), and the pressure was kept constant at 1 atm. Two reaction mechanisms were attempted: a global single-step irreversible reaction for complete combustion and the GRI-Mech 3.0 elementary mechanism (53 species, 325 steps) for chemical equilibrium with its associated thermodynamic data. NASA CEARUN was the main modeling tool used. Two other tools were used for benchmarking: an Excel and a Cantera-Python implementation of GRI-Mech 3.0. The results showed that the AFTs for oxy-methane were 5,166.47 K (complete combustion) and 3,050.12 K (chemical equilibrium), and dropped to 2,326.35 K and 2,224.25 K for air-methane, respectively. The AFTs for oxy-hydrogen were 4,930.56 K (complete combustion) and 3,074.51 K (chemical equilibrium), and dropped to 2,520.33 K and 2,378.62 K for air-hydrogen, respectively. For eight combustion modeling cases, the relative deviation between the AFTs predicted by CEARUN and GRI-Mech 3.0 ranged from 0.064% to 3.503%. [ABSTRACT FROM AUTHOR]

Lithium-ion battery cells exhibit a complex and nonlinear coupling of thermal, electrochemical, and mechanical behavior. In order to increase insight into these processes, we report the development of a pseudo-three-dimensional (P3D) thermo-electro-mechanical model of a commercial lithium-ion pouch cell with graphite negative electrode and lithium nickel cobalt aluminum oxide/lithium cobalt oxide blend positive electrode. Nonlinear molar volumes of the active materials as function of lithium stoichiometry are taken from literature and implemented into the open-source software Cantera for convenient coupling to battery simulation codes. The model is parameterized and validated using electrical, thermal and thickness measurements over a wide range of C-rates from 0.05 C to 10 C. The combined experimental and simulated analyses show that thickness change during cycling is dominated by intercalation-induced swelling of graphite, while swelling of the two blend components partially cancel each other. At C-rates above 2 C, electrochemistry-induced temperature increase significantly contributes to cell swelling due to thermal expansion. The thickness changes are nonlinearly distributed over the thickness of the electrode pair due to gradients in the local lithiation, which may accelerate local degradation. Remaining discrepancies between simulation and experiment at high C-rates might be attributed to lithium plating, which is not considered in the model at present. [ABSTRACT FROM AUTHOR]

Copyright of Ciencia, Tecnología y Salud is the property of Ciencia, Tecnologia y Salud and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A rotating detonation engine (RDE) is a highly promising detonation-based propulsion system and has been widely researched in recent decades. In this study, BYCFoam, the latest gaseous version of the BYRFoam family, is developed specifically for RDE simulations. It is based on the standard compressible flow solver rhoCentralFoam in OpenFOAM and incorporates several enhancements: improved reconstruction variables and flux schemes; detailed chemistry and transport properties; the utilization of an adaptive mesh refinement (AMR) and dynamic load balancing (DLB). A series of comprehensive numerical tests are conducted, including the shock-tube problem, shock-wave diffraction, homogeneous ignition delay, premixed flame, planar detonation, detonation cellular structure and rotating detonation combustor (RDC). The results demonstrate that BYCFoam can accurately and efficiently simulate the deflagration and detonation processes. This solver enhances the capability of the BYRFoam family for the in-depth exploration of RDE in future research.

Las canteras de calizas y conglomerados – “jaspe” – de Espejón (Soria) y Huerta de Rey (Burgos) esconden un valor añadido al hasta ahora impuesto por su utilización como piedra ornamental en grandes programas monumentales, entre los que destacan las catedrales de Toledo, Burgos y Segovia, El Monasterio de El Escorial o el Palacio Real (Madrid). Un análisis más amplio de los originales de los siglos XVI al XVIII, revelan su importancia en el proceso de estratificación de la sociedad del Antiguo Régimen, dado que la Monarquía, los Concejos de Huerta de Rey y Espejón y el Monasterio de San Jerónimo de Espeja lucharon por su control como fuente de poder.

Copyright of Human Review is the property of Eagora Science and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

• A machine learning model that can predict laminar flame speed of pure fuels and fuel blends is developed. • Reduced cost and time of computational models requiring laminar flame speed of fuel blends. • Robust framework that can capture the laminar flame speed of conventional fuel blends and lithium-ion battery vented gases. • Extended practical parametric domain considerations for laminar flame speed computation. A data-driven machine learning (ML) model for predicting laminar flame speeds (LFS) of common fuel–air mixtures is developed, with a major advantage of being convenient and prompt to be used at various temperatures, pressures, equivalence ratios and various compositions for both single and multi-compounds fuels. Specifically, combining (i) Cantera, an open-source software for modeling chemical kinetics, thermodynamics, and transport processes and (ii) the regression learner model, the newly developed model is able to predict the LFS for various fuels and fuel blends, including those of hydrogen, hydrocarbons such as methane, ethane, propane as well as combustible gases from lithium-ion batteries. A total of 75,000 data points has been generated for the model development, with a total of 24 various ML models available in the MATLAB regression learner applications being trained and verified using the 75 % of the total data, while the remaining 25 % of the data, randomly selected, were used for validation purposes. The Matern 5/2 GPR model has demonstrated the best performance out of the 24 ML models considered. In addition to comparison with Cantera, the developed ML-LFS model has been further validated using experimental data from the literature. Overall, the newly developed ML-LFS model provides a good prediction for the LFS of pure fuels, binary fuel blends, and ternary fuel blends at various parametric conditions. The ML model offers a significant reduction in computational time and cost in computing the LFS. [ABSTRACT FROM AUTHOR]

Tarragona's physiognomy was transformed due to the fortifications, the exploitation of the quarries and the bulk earthworks for the urban expansion. Agustín Elcoro Berecíbar introduced the tramway for the transport of large rocks. Amado de Lázaro designed a tramway to speed up the grading works of the Rambla Nova and varied the quarrying of the port. In addition, this analysis highlights the relationship between the quarries and the progress of the port works, as well as the alteration of the urban landscape and the development of domestic architecture. [ABSTRACT FROM AUTHOR]

Copyright of Revista Kronos is the property of Revista Kronos and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Retos: Nuevas Perspectivas de Educación Física, Deporte y Recreación is the property of Federacion Espanola de Asociaciones de Docentes de Educacion Fisica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We describe the implementation of several thermo-chemical analyses in Cantera and the Shock and Detonation Toolbox (SDT), that can be employed to investigate the chemical dynamics of planar steady detonation. A MATLAB graphical user interface has also been developed to post-process the data provided by the detonation codes. These utilities will be made available on request and in the future releases of the SDT. [ABSTRACT FROM AUTHOR]

El objetivo de este estudio fue analizar y determinar la revalorización en el mercado de los jugadores de fútbol de los equipos filiales de una liga de fútbol profesional. Se llevó a cabo un análisis descriptivo donde participaron los jugadores de fútbol de los equipos filiales de LaLiga Santander de la temporada 19-20 (n=144) de edades entre 17 y 26 años (M=22.34±2.18). Los resultados más relevantes muestran como la mayoría de los jugadores están tan solo 4 años formándose en el club, con una revalorización en el mercado al cabo de tres años de 15.57 millones de euros de media, siendo aquellos que se incorporan al club en edad cadete e infantil los que más valor suelen obtener al cabo del tiempo. Se puede concluir que los procedimientos utilizados en esta investigación pueden ser de gran utilidad para analizar el proceso formativo el jugador de fútbol y la rentabilidad que este genera en sus clubes. Abstract. The aim of this study was to analyze and determine the market revaluation of U23 football players from professional league clubs. A descriptive analysis was carried out with the participation of football players from LaLiga Santander subsidiary teams in the 19-20 season (n=144) aged between 17 and 26 years (M=22.34±2.18). The most relevant results show that the majority of the players are only 4 years training in the club, with a revaluation in the market after three years of 15.57 million euros on average, being those who join the club at U15-16 and U13-U14, the ones that tend to obtain the most value over time. It can be concluded that the procedures used in this research can be of great use in analysing the training process of the football player and the profitability that he generates for his club.

The Court of Justice of the European Union issued a judgment on Directive 2011/92, which deals with the assessment of the impact of projects on the environment. The case refers to an exception granted to a company for the exploitation of a quarry in Belgium. The court determined that the previous administrative decision exempting the application of species protection measures does not require public participation and is part of the project authorization procedure. Although the exception was granted, the project was ultimately rejected. [Extracted from the article]

A complete description of the thermodynamic behavior of an Otto cycle engine is obtained in terms of shaft rotation angle by a Python code. From results, indicators of high technical relevance are calculated, including effective pressure, specific break power, specific fuel consumption and volumetric efficiency. The proposed transient model solves transient mass and energy balances including compressible flow through the valves and combustion speed. The implemented code is validated by comparing numerical results with experimental measurements of an engine operating without combustion stage and at constant angular speed. By using the developed method, more conservative and realistic results are found for, among other indicators, thermal efficiency, volumetric efficiency and effective average pressure, and it is possible to predict the thermodynamic behavior of Otto cycle engines in an accurate and efficient way. [ABSTRACT FROM AUTHOR]

Se obtiene una completa descripción del comportamiento termodinámico de un motor tipo Otto en función del ángulo de giro del eje mediante un código en lenguaje Python. A partir de los resultados, se estiman indicadores de alta relevancia técnica como la presión efectiva indicada, la potencia específica de freno, el consumo específico de combustible y la eficiencia volumétrica. El método propuesto soluciona balances de masa y energía en estado transitorio incluyendo flujo compresible a través de las válvulas y velocidad de combustión. La validación del código implementado se realiza mediante comparación con mediciones experimentales para funcionamiento de motor en modo de arrastre y a condiciones de velocidad angular constante. Empleando la metodología desarrollada, se encuentran resultados más realistas para, entre otros indicadores, la eficiencia térmica, eficiencia volumétrica y la presión media efectiva, y es posible predecir de manera precisa y eficiente el comportamiento termodinámico de motores tipo Otto.

Una de las rocas sedimentarias con gran utilidad en la industria de la construcción, agricultura, manufactura, metalurgia, entre otras; es la roca caliza. La cuales materia prima para la fabricación del yeso, cal, cemento, concretos, estucos entre otros; debido a esto, la demanda para la obtención de dicho material ha aumentado en los ́últimos años, encontrándonos hoy con m ́as demanda que oferta, lo cual hace importante que se obtenga un buen aprovechamiento teniendo en cuenta sus diferentes propiedades físicas y químicas. En el municipio de Bosconia, departamento del Cesar se encuentran en superficie rocas sedimentarias, las cuales están siendo extra ́ıdas por diferentes canteras tales como Minera de los Santos, Cantera Midas y Eliseo Cañón para su aprovechamiento industrial. En este artículo se determinaron mediante ensayos de fluorescencia de rayos x, mecánica y petrografía los diferentes usos de las Calizas aflorantes en dichas canteras, por medio de estos ensayos se evidencio que las calizas encontradas en la zona poseen una concentración de calcio entre94.39%y45.45%, sílice entre35%y2.88%y otros como Fe, K, Al, Mg y S que no superan el1%; según las normas NTC 4915 [1] (ICONTEC)equivalente a la ASTM C 911-99 [2], la utilidad de las rocas extraídas en la mina Eliseo Cañón y Minera de los Santos es para descalcificación de agua, tratamiento de aguas e hipoclorito (blanqueador), y para pulpa de papel solo las de Eliseo Cañón. De igual formase realizaron ensayos de compresión uniaxial, arrojando valores de compresión uniaxial:6.3Mpa; 5.9Mpa; 4.9Mpa respectivamente

Copyright of Spal: Revista de Prehistoria y Arqueologia de la Universidad de Sevilla is the property of Spal. Revista de Prehistoria y Arqueologia de la Universidad de Sevilla and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

El contenido se focaliza en conseguir una reconstrucción ideal y un entendimiento, a través de la comparación y de los principios básicos constructivos y geométricos de modelos semejantes, de uno de los elementos arquitectónicos más característicos y representativos de la Arquitectura del Renacimiento Andaluz: el soporte. Para ello se propone como objeto de estudio las ruinas de la Iglesia de Santa Mará de Cazorla, cuyo estado inconcluso permite utilizarlas como tapiz sobre el que encajar piezas inexistentes que derivan del análisis estilístico, geométrico y formal que, por comparación, podemos deducir de arquitecturas equivalentes. La idealización de los modelos permitirá que el estudio de los soportes pueda acercarse con precisión sobre los requerimientos espaciales, métricos y constructivos que se detectan.

Se evaluó el desempeño de los indicadores económicos en las canteras de materiales de la construcción de la Empresa de Canteras de La Habana. La investigación se desarrolló a través de tres etapas metodológicas que posibilitaron evaluar los principales indicadores de la actividad económica de una cantera a través de la identificación de los indicadores económicos para la evaluación del desempeño de canteras, selección de los indicadores económicos aplicables a las canteras de materiales de construcción a través de criterio de expertos y caracterización de los indicadores económicos para la evaluación del desempeño de canteras de materiales de construcción. A pesar de que los resultados económicos fueron deficientes en el periodo productivo, la cantera genera utilidades.

In order to reduce computing costs in the calculation of combustion in cooktops burning methane-hydrogen mixtures, automatic reduction techniques have been used to develop a reduced mechanism for atmospheric, methane-hydrogen-air flames involving 26 species and 143 reactions starting from GRI-Mech 3.0. Validation for 0-D and 1-D calculations shows good agreement with the original mechanism for gas mixtures ranging from pure methane up to a 1:1 methane-hydrogen ratio, showing that it can be used for a variety of methane-hydrogen mixtures. An improved, customized OpenFOAM solver has been developed and employed to perform 2-D and 3-D calculations. Results from a computational experiment for an axisymmetric, partially premixed flame are in good agreement with the original mechanism and with published experimental results. Flame stability has been studied in realistic 3-D methane-hydrogen cooktop calculations. Using the reduced mechanism, light back phenomena are reproduced accurately while providing a fourfold speed-up over the original mechanism. • A reduced chemical mechanism for methane-hydrogen cooktops with 26 species. • Very good agreement for atmospheric 0D/1D flames, various methane-hydrogen contents. • Good agreement for atmospheric 2D/3D flames (OpenFOAM). • Transient analysis of light back events in a cooktop with several mechanisms. • It replicates light back in 3D simulations of a cooktop burner, with a 4x speedup. [ABSTRACT FROM AUTHOR]

The following paper compares experiments with the performance of a simplified numerical model aimed at estimating surface temperatures of a mesoscale, combustion-driven, heat recirculating parallel channel reactor. Simplification is enabled by discretizing the domain of interest using a series of perfectly stirred reactors. This approach avoids the treatment of convective and diffusive transport and instead focuses on chemistry and heat transfer. An end user of the model is empowered to casually vary system parameters to satisfy a latent curiosity or as part of a larger parametric analysis, both of which are, otherwise, computationally expensive. Once designed, the reactor will serve as a heat source for a thermal-to-electrical energy convertor when coupled to a thermophotovoltaic receiver. All simulations are performed using Cantera: an open-source chemical kinetics library, which defines a set of abstracted forms to be used as building blocks to study the interaction between chemistry and heat transfer in a simplified geometry. The utility of this approach is demonstrated by assessing energy loss mechanisms through various surfaces, an impractical feat experimentally. The code developed as a part of this effort will be made available in an online repository. [ABSTRACT FROM AUTHOR]

El texto describe y dibuja una estrategia de recuperación ecológica de una explotación minera de piedra ornamental en activo, situada en el entorno del parque arqueológico del Tolmo de Minateda, en el Término municipal de Hellín (Albacete, España). En el año 2015, la empresa Areniscas Rosal, propietaria de los derechos de explotación de dicha cantera, encargó a la oficina de Arquitectura y Urbanismo SSS (Spanish Studio of Space) un Plan de Restauración para establecer las directrices básicas de una recuperación paisajística que revierta el impacto de la actividad extractiva en un futuro próximo. El proyecto, fundamentado en la filosofía del Land Art, es una reconstrucción geométrica del terreno por medio de la reutilización de los sobrantes de la propia actividad, para así crear un paisaje totalmente nuevo y contemporáneo. El reciclaje, la re-vegetación y una solución proyectual innovadora fundamentan las directrices de esta intervención paisajística y territorial. Las posibilidades de reutilización y disfrute de este nuevo entorno natural podrán ser variadas y enriquecedoras y solo dependerán de una gestión sensible y respetuosa de la relación del hombre con la naturaleza. The former document describes and draws a strategy of ecological recovery of an ornamental stone mine in active, located in the archaeological park environment of Tolmo de Minateda in the municipality of Hellín (Albacete, Spain). Back in 2015, the company Rosal Sandstones, which owns the rights to exploit the quarry, commissioned the Office of Architecture and Urbanism SSS (Spanish Studio of Space) a Restoration Plan in order to establish the basic guidelines for a landscape recovery to revert the impact of mining activity in the near future. The project, based on the philosophy of Land Art, is a geometric reconstruction of the ground by means of reusing the leftovers of the activity itself, to thereby create a totally new and contemporary landscape. Recycling, re-vegetation and innovative design methodology solutions substantiate the guidelines of this landscape and territorial intervention. The possibilities for re- usability and enjoyment of this new natural environment can be diverse and enriching and, only depend on a sensitive and respectful management of the relationship between man and nature.

Underground coal gasification (UCG) is an in situ conversion technique that enables the production of high-calorific synthesis gas from resources that are economically not minable by conventional methods. A broad range of end-use options is available for the synthesis gas, including fuels and chemical feedstock production. Furthermore, UCG also offers a high potential for integration with Carbon Capture and Storage (CCS) to mitigate greenhouse gas emissions. In the present study, a stoichiometric equilibrium model, based on minimization of the Gibbs function has been used to estimate the equilibrium composition of the synthesis gas. Thereto, we further developed and applied a proven thermodynamic equilibrium model to simulate the relevant thermochemical coal conversion processes (pyrolysis and gasification). Our modeling approach has been validated against thermodynamic models, laboratory gasification experiments and UCG field trial data reported in the literature. The synthesis gas compositions have been found to be in good agreement under a wide range of different operating conditions. Consequently, the presented modeling approach enables an efficient quantification of synthesis gas quality resulting from UCG, considering varying coal and oxidizer compositions at deposit-specific pressures and temperatures.

This study evaluates the performance of the CALPUFF model to estimate PM10 environmental concentrations caused by emissions from a quarry located in mountainous terrain in northern Colombia. The pollutant dispersions were simulated for a 22 km x 18 km domain with an approximate resolution of 100 meters. Predictions of the average concentrations of PM10 from the sources to the receptors were 17.50 μg/ m3 (<1km), 4.06 μg/m3 (<2km), 2.16 μg/m3 (<3km) and 0.82 μg/m3 (<6km). Although the model underestimated the concentration, it showed a satisfactory performance and acceptance criteria framed within the statistical indicators used to evaluate environmental models. The model showed an acceptable capacity to estimate PM10 concentrations in complex terrain due to the use of data from meteorological stations near sources, accuracy in the emissions inventory as a function of space-time, location of receptors for model validation and higher resolution of the domain area of the modeling that were not contemplated in previous studies. [ABSTRACT FROM AUTHOR]

Here, we study real gas effects on high-pressure combustion by comparing simulated and experimentally-measured shock tube ignition delay measurements for n-dodecane/O 2 /N 2 mixtures. Experiments and simulations occur at conditions relevant to diesel engines: 40–80 atm, 774–1163 K, equivalence ratios of 1.0 and 2.0, and O 2 concentrations of 13–21%. At these conditions the fuel, oxidizer and intermediate species may exist in a supercritical state during combustion, requiring a real gas equation of state to incorporate non-ideal effects on thermodynamics, chemical kinetics, and the resulting ignition characteristics. A constant-volume, adiabatic reactor model is developed to simulate the reflected shock tube experiments, and simulations compare results for real and ideal gas equations of state, with different expressions for reacting species’ activity concentrations. This paper focuses particularly on the cubic Redlich–Kwong equation of state and thermodynamically consistent chemical kinetic rate calculations based on it. Results demonstrate that the equation of state can have considerable influence on ignition delay times with increasing pressure, particularly in the negative temperature coefficient region. Additionally, the results establish important practices for incorporating real gas effects, namely that (i) the compressibilities of key species (i.e. those participating in rate-limiting reactions) are the appropriate way to screen for real gas effects, rather than the average mixture compressibility; and (ii) incorporating a real gas equation of state without also incorporating thermodynamically consistent chemical kinetics significantly under-predicts the magnitude of real gas effects. [ABSTRACT FROM AUTHOR]

La explotación de la cantera de materiales de la construcción Castellano, en la provincia de Pinar del Río, provoca impactos negativos al medio ambiente. Se propuso un plan de medidas para mitigar los efectos negativos que la cantera ocasiona al medio, el cual, además, favorece el fortalecimiento de las consecuencias positivas que produce la explotación del yacimiento sobre el medio ambiente. Las medidas elaboradas permiten mitigar los efectos negativos y potenciar los positivos que produce la explotación del yacimiento sobre el medio ambiente.