Review of Contribución del Análisis Espacial a la Ciencia y a la Geografía. Referencia Histórico-Bibliográfica

El libro del profesor Darío César Sánchez que se presenta en esta reseña aporta un “riguroso análisis de la evolución a través del tiempo del concepto y método del análisis espacial en la ciencia y en la Geografía”, con el objetivo de contribuir al debate científico, a la reflexión teórica y a la formación y al desarrollo de un sentido crítico entre los “jóvenes científicos sociales argentinos y latinoamericanos”.</jats:p

Las salas de cine en Madrid. De los primeros cinematógrafos a la demanda por «salvar» los cines históricos de la ciudad

From the appearance of the first filmmakers to the opening of the large multiscreen cinemas in modern shopping malls, cinema attendance in the city of Madrid has run parallel to the changes that have affected its demand within different social and cultural contexts. This paper discusses the changes caused by this fact in shaping the film exhibition space in Madrid over time and in recent decades, a phase in which its development has been influenced by the closure of cinemas, the development of new business formulas that have altered the characteristics of conventional cinemas and the distribution of the audience, and the emergence of new demands to ensure the preservation of historical cinemas for their heritage value.Desde la aparición de los primeros cinematógrafos, hasta la inauguración de las grandes salas en los modernos centros comerciales, la frecuentación al cine en la ciudad de Madrid ha corrido en paralelo a los cambios que han afectado a su demanda en el marco de diferentes contextos sociales y culturales. En este trabajo se analizan los cambios que ha provocado este hecho en la conformación del espacio de exhibición cinematográfico madrileño a lo largo del tiempo y en las últimas décadas, fase en la que su desarrollo ha estado condicionado por los cierres de locales, el desarrollo de nuevas fórmulas de negocio que han alterado las características del cine convencional y la distribución territorial del aforo, y la emergencia de nuevas demandas para garantizar la conservación de los locales históricos del cine por sus valores patrimoniales

Los museos, oferta consolidada para el turismo sostenible y la calidad del paisaje

The International Council of Museums (ICOM) and the World Federation of Friends of Museums (WFFM) for worldwide Sustainable Cultural Tourism acknowledge that museums constitute an example of sustainable cultural tourism for a society with increasing free time and the ability to move for reasons of leisure and tourism. This paper analyzes the evolution of museums since their initial function of gathering material for its conservation to the current situation, in which museums form part of the tourism offer and compete among themselves to increase the number of visitors, and enhance feelings of a collective identity and of respect and tolerance towards other cultures in accordance with the Charter for Sustainable Tourism of 1995. Museums also contribute, through tourism, to generating employment and enhancing the landscape following strategies of the Convention of the European landscape of 2000.El Consejo Internacional de Museos (ICOM) y la Federación Mundial de Amigos de los Museos (WFFM) reconocen los museos como oferta de turismo cultural sostenible para una sociedad cada vez con más tiempo libre y capacidad de desplazarse por ocio y turismo. En este artículo se analiza la evolución de los museos desde su primera función de acopio de materiales para su conservación hasta la situación actual, en la que forman parte de la oferta turística y compiten para aumentar sus visitantes, potenciando sentimientos de identidad colectiva y de respeto y tolerancia hacia otras culturas, de acuerdo con la Carta del Turismo Sostenible de Lanzarote de 1995. Los museos contribuyen también a través del turismo a la generación de empleo y a la puesta en valor del paisaje siguiendo estrategias de la Convención del Paisaje Europeo de 2000

Thermo-economic and sensitivity analysis of a central tower hybrid Brayton solar power plant

[EN]A hybrid central tower thermo-solar plant working with a gas turbine is simulated by means of an in-house developed model and software. The model considers the integration of all plant subsystems. The calculation of the heliostat solar field efficiency includes the main losses factors as blocking, shadowing, attenuation, interception, and cosine effect. The simulation considers a Brayton cycle for the power unit with irreversibilities in the compressor and turbine, and pressure drops in the heat absorption and extraction processes. A combustion chamber burning natural gas ensures an approximately constant power output. The model is flexible and precise. At the same time it is fast enough to perform sensitivity studies on the efficiency of any subsystem and the overall plant. Thus, it allows for performing a thermo-economic analysis of the plant checking the influence of the main plant design parameters. The focal objective is to analyze the importance on the levelized cost of electricity (LCoE) of the key plant design parameters. The direct influence of parameters from the heliostat field and receiver (as tower height, distance to the first row of heliostats, heliostats size, receiver size and heat losses, etc.) on final LCoE is surveyed. Similarly, parameters from the turbine as pressure ratio, turbine inlet temperature, influence of recuperation and others, are also analyzed. The dimensions of the plant are taken from SOLUGAS prototype near Seville, Spain, although another location with quite different solar conditions in Spain is also considered. LCoE values predicted are about 158 USD/MWh. The analysis concludes that among several parameters surveyed, two of them are key in LCoE predicted values: turbine inlet temperature and solar receiver aperture size.Junta de Castilla y León of Spain (project SA017P17

Towards a Sustainable Future through Renewable Energies at Secondary School: An Educational Proposal

[EN]A compilation of innovative educational activities to work on concepts related to the production of electrical energy is presented. To approach the real-life secondary education curriculum, they are grouped to be performed during a week denominated Renewable Energy Week: an educational proposal aimed to promote the respect for the environment through the insight on Sustainable Development Goals (SDG) and renewable energy sources. The students would build and perform low-cost experiments so as to deeply understand the essence of energetic transformations, as well as electricity generation. Learning by discovery, collaborative learning and experimentation, are the methodological pillars that characterize Renewable Energy Week, since they have been proven to be efficient methodologies to promote students’ learning. Innovative techniques for pupils evaluation are employed, including a rubric, Socrative application and a set of sheets regarding experiments. Through this educational proposal, the students are expected to achieve a deep understanding of some key concepts related to electricity and awaken their interest in scientific subjects, making them conscious of the transition to sustainable development that our planet urgently requires. At the same time, this project offers to teachers a series of experiments and innovative activities to work on the SDG in Physics, Chemistry and Technology subjects.University of Salamanca through Innovation and teaching improvement project ID 2019/16

Study of size effects on the peak and residual strength of intact and artificially fissured granite samples

There are not many studies on jointed rock specimens, which can be considered small scale rock mass analogs. On the other hand, the scale effects in the mechanical properties of such samples have seldom been studied. With the aim of continuing previous research on intact granite rocks, the authors have carried out sets of 25 stress-strain triaxial compressive tests on 1 sub-vertical and 2 sub-horizontal 38 mm, 54 mm and 84 mm diameter jointed granite specimens at various confinements. Peak and residual strength values were obtained and compared to those recovered form intact rock samples. Results suggest that peak strength follows similar trends with scale to those observed on intact rock, even if lower strength values are logically recorded. Regarding residual strength, the obtained results are in line with those observed trends for standard size samples, showing a similar trend for all cases independently of scale, even if we observe larger variability for jointed samples. The authors have also compared the values fitting the generalized Hoek-Brown criterion for rock masses to better understand the behavior in relation to sample size. So scale effects clearly appear on jointed rock peak strength of jointed sample; even if residual strength seems hardly affected by scale.Agencia Estatal de Investigación | Ref. RTI2018-093563-B-I0

Thermo-economic study of hybrid parabolic dish solar power plants in different regions of Spain

[EN]Small-scale hybrid parabolic dish Concentrated Solar Power (CSP) systems coupled to a micro-gas turbine are a promising option to obtain electrical energy in a distributed manner. During the day, solar energy is used to produce electricity and the absence of sunlight can be overcome with the combustion of a fossil or renewable fuel. This study presents the technical feasibility and thermo-economic model of a hybridized power plant in different regions of Spain, considering the local climatic conditions. The implemented model aims to provide a realistic view of the behaviour of the system, using a reduced number of selected parameters with a clear physical meaning. The irreversibilities taking place in all subsystems (solar part, combustion chamber, micro-gas turbine, and the corresponding heat exchangers) have been considered in the model, developed in Mathematica® language. The model considers the instant solar irradiance and ambient temperature dynamically, providing an estimation of the power output, the associated fuel consumption, and the most relevant pollutant emissions (CO2, CH4 and NO2) linked to combustion, for hybrid and combustion only operating modes at selected geographical locations in Spain. The considered power output ranges between 7 to 30 kWe which is achieved by varying the design specifications. The levelized cost of electricity (LCoE) indicator is estimated as a function of investment, interest rate, maintenance and fuel consumption actual costs in Spain. The electricity costs from hybrid parabolic dish are between 22% and 27% lower compared to pure combustion power plant, while specific fuel consumption and therefore CO2 emissions can be reduced up to 33%. This model shows the potential of hybrid solar dishes to become cost-competitive against non-renewable ones from the point of view of electricity costs and significant reduction in gas emission levels in regions with high solar radiation and low water resources.Junta de Castilla y Leó

Micro Gas Turbine and Solar Parabolic Dish for distributed generation

[EN]A thermodynamic model for a Brayton-like microturbine in combination with a solar parabolic dish is analyzed in order to evaluate its efficiency under any ambient condition. The thermodynamic cycle is a recuperative Brayton cycle with internal irreversibilities in the recuperator, compressor and turbine and external losses associated to the heat transfers in the solar receiver, the combustion chamber, and the environment. All the irreversibilities have been taken into account in the model with home-software elaborated using Mathematicaâ. The model validation is done by comparison with results provided by Semprini et al. [1]. An analysis of hybrid and sunless performance is carried out for four different microturbine power outlets (30, 23, 15 and 7 kWe) and for four days of the year (corresponding to each season). The greenhouse emissions are also calculated for both off-design performance and for the four power output levels