4,849 research outputs found

    Assessment of the performance of X-band satellite radar data for landslide mapping and monitoring: Upper Tena Valley case study.

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    Abstract. The aim of this work is to analyse the advantages and disadvantages of using the new X-band SAR data acquired by TerraSAR-X sensors for landslides mapping. This dataset has been processed using a Persistent Scatterer Interferometry technique over the Upper Tena Valley (Central Pyrenees, Spain). In the first section, the geological and geomorphological setting of the study area is introduced, focusing on the description of the landslide inventory. Then the Stable Point Network technique is briefly described, followed by the assessment of the performance of the X-band SAR dataset. In this context, we present first a model to predict the distribution of Persistent Scatterers based on the slope geometry and the land use information, which has then been validated with X-band data results. On a second stage, we have assessed the performance of X-band dataset to detect and monitor mapped landslides. Finally some illustrative case studies are shown demonstrating the potential of using X-band SAR data not only for landslide mapping but also to detect and monitor deformations affecting human infrastructures

    Gamma Ray Bursts: Observations and Theoretical Conjectures

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    Gamma Ray Bursts (GRBs) are short bursts of very high energy photons which were discovered in the late 1960s. Ever since their discovery, scientists have wondered about their origin. Nowadays it is known that they originate outside the Milky Way because of their high red shift rst measured in the afterglows thanks to the Beppo-SAX satellite and ground-based observations. However, theoreticians still do not agree about the mechanism that generates the bursts, and different competing models are animatedly debated. Current GRB experiments include the Swift satellite and the Pierre Auger Observatory that could detect GRBs with an increase of the background. A forthcoming dedicated experiment is GLAST, a satellite observatory for detecting gamma rays with energies up to 300 GeV, whose launch is scheduled for early 2008

    Geoenvironmental Analysis of Oil Extraction Activities in Urban and Rural Zones of Santa Elena Province, Ecuador

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    From an environmental viewpoint, oil wells can be considered a potential source of pollution when improperly managed. The Santa Elena province (Ecuador), located on the Pacific coast, currently has a residual crude oil extraction compared to production generated in the Amazon region of the country. However, this activity in the coastal zone is very near to urban and rural populations. Therefore, a detailed influence analysis of these wells on the environment is necessary. This work aims to analyse, from a geoenvironmental perspective, the oil wells impact located in a pilot zone (urban and rural) of the oil field studied and, complementarily, to describe their incidence on the community and territory. The methodological process includes (i) oil wells compilation and inventory within the study zone and selection of a pilot zone; (ii) contaminating factors identification generated by the wells infrastructure (mechanical and territorial) and their current state of activity (production or abandoned); (iii) environmental impacts analysis generated through the development of a cause-effect matrix and, finally, the evaluation of a method and results found through a focus group technique. The results reflect a negative impact on the land cover and vegetative-animal environment in the vicinity of the wells, caused by the continuous release of gases, metallic oxidation and bituminous exhumation. The overall impacts interpretation compiled indicates that comprehensive action is needed at the wells to control and minimise them. The implementation of new environmental strategies through zoning can help to achieve adequate land-use planning, thus combining the safe and sustainable use of the resource with the development of other community activities (urbanisation, tourism, industry, agriculture and fishing) and environmental protection.This work was carried out in collaboration with the ‘Peninsula Santa Elena Geopark Project’ with code no. 91870000.0000.381017, and ‘Factores Geoambientales de los pozos petroleros y su incidencia en el desarrollo territorial en los cantones Salinas y La Libertad de la provincia de Santa Elena’, with code no: 91870000.0000.385428, by UPSE University. Support for the project was also provided by the ‘Registry of geological and mining heritage and its impact on the defence and preservation of geodiversity in Ecuador’, academic research project by ESPOL University, CIPAT-01-2018

    Analysis of Sugarcane Ethanol Production for Energy Development: Case Study Ecuador

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    The global energy issue is crucial for the development of the population and the environmental protection of the planet. The agricultural sector is part of economic, social and environmental development. However, in Ecuador, this sector has internal problems due to the suspension of the bioconversion project (e.g., ethanol production). This study aims to analyse the situation of sugarcane ethanol production in Ecuador and, through information management, to search for development strategies. The methodology includes the following: (i) sugarcane production analysis in Ecuador and ethanol distribution; (ii) policies and legal context concerning renewable energies and biofuels production in Ecuador; (iii) Political, Economic, Social, Technological, Ecological and Legal (PESTEL) as well as Strengths, Weaknesses, Opportunities and Threats (SWOT) analysis of ethanol production, based on the criteria of the experts involved and (iv) strategic guidelines for sustainable sugarcane ethanol development. Ecuador has a potential for sugarcane ethanol production that is currently not fully exploited; that is, the consumption of this resource would reduce energy demand and economic problems in the agricultural sector. Sugarcane ethanol production has generated a direct contribution to the country’s Gross Domestic Product (0.5%) and a contribution to social growth (751,799 people benefited). Ethanol production could increase by 20%, generating new alternatives for biofuel consumption. This progress in Ecuador would strengthen the contribution to the Sustainable Development Goals criteria and benefit the population with new job opportunities (approximately 42,000). Therefore, the production of ethanol from sugarcane, under a legal framework, benefits economic, social and ecological relations.This work had the collaboration of several business associations, such as the Asociación de Productores de Caña de Azúcar del Cantón Milagro (APCAM) and the Asociación de Biocombustibles del Ecuador (APALE). Alejandro Gallardo and Orlando Zambrano participated in APCAM. In APALE, Gustavo Heinert (president) and Carlos León (analyst) participated. In addition, had the collaboration to project of the ESPOL Polytechnic University such as “Registry of geological and mining heritage and its impact on the defence and preservation of geodiversity in Ecuador” with code CIPAT-01-2018

    Scale dependence of the quark masses and mixings: leading order

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    We consider the Renormalization Group Equations (RGE) for the couplings of the Standard Model and its extensions. Using the hierarchy of the quark masses and of the Cabibbo-Kobayashi-Maskawa (CKM) matrix our argument is that a consistent approximation for the RGE should be based on the parameter λ=V^ud0.22\lambda= |\hat{V}_{ud}| \approx0.22. We consider the RGE in the approximation where we neglect all the relative terms of the order λ4\sim\lambda^{4} and higher. Within this approximation we find the exact solution of the evolution equations of the quark Yukawa couplings and of the vacuum expectation value of the Higgs field. Then we derive the evolution of the observables: quark masses, CKM matrix, Jarlskog invariant, Wolfenstein parameters of the CKM matrix and the unitarity triangle. We show that the angles of the unitarity triangle remain constant. This property may restrict the possibility of new symmetries or textures at the grand unification scale.Comment: 15 pages, 4 figures, author of one reference adde

    Bibliometric Analysis and Review of Low and Medium Enthalpy Geothermal Energy: Environmental, Economic, and Strategic Insights

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    Received: 10 July 2023. Revised: 30 July 2023. Accepted: 8 August 2023. Available online: 25 September 2023.Geothermal energy, an efficacious and readily available resource, has emerged as a sustainable alternative poised to satisfy escalating global energy demands. This study undertakes a comprehensive analysis of low (heat below 100℃) and medium (heat between 100℃ to 150℃) enthalpy geothermal energy through a bibliometric approach and a literature survey, with an emphasis on the environmental and economic aspects. The methodological procedure encompasses: (i) systematic information processing and configuration, (ii) bibliometric assessment of the evolution and domains of the investigated field, (iii) evaluation of environmental and economic contributions, and (iv) Strengths, Weaknesses, Opportunities and Threats (SWOT) analysis, facilitated by a Focus Group comprising experts from the energy sector. The research on low and medium enthalpy geothermal energy has been identified as an expanding field, with five primary areas of focus: sustainability, cascade systems, heat pumps, numerical modelling, and roundwater potential in geothermal systems. Italy, the United States, and Germany have been recognized as the leading contributors in terms of scientific production. Geothermal energy, from an environmental standpoint, aids the decarbonisation process, reducing reliance on fossil fuels and other renewable energy sources. Although initial investment costs are considerable, the financial recovery period is relatively short. The promotion of geothermal energy, alongside the active involvement of academia, corporations, and governments, bolsters energy and socio-economic development, thereby contributing to the achievement of the Sustainable Development Goals (SDG).This work is supported by ESPOL Polytechnic University research project "Register of geological and mining heritage and its incidence in the defence and preservation of geodiversity in Ecuador" with institutional code CIPAT-01- 2018, and Instituto de Investigación Geológico y Energético (IIGE). We would also like to thank the editorial office for the editorial handling and four anonymous reviewers for their constructive comments and corrections

    Localization of gravity on a de Sitter thick braneworld without scalar fields

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    In this work we present a simple thick braneworld model that is generated by an intriguing interplay between a 5D cosmological constant with a de Sitter metric induced in the 3-brane without the inclusion of scalar fields. We show that 4D gravity is localized on this brane, provide analytic expressions for the massive Kaluza-Klein (KK) fluctuation modes and also show that the spectrum of metric excitations displays a mass gap. We finally present the corrections to Newton's law due to these massive modes. This model has no naked singularities along the fifth dimension despite the existence of a mass gap in the graviton spectrum as it happens in thick branes with 4D Poincare symmetry, providing a simple model with very good features: the curvature is completely smooth along the fifth dimension, it localizes 4D gravity and the spectrum of gravity fluctuations presents a mass gap, a fact that rules out the existence of phenomenologically dangerous ultralight KK excitations in the model. We finally present our solution as a limit of scalar thick branes.Comment: 11 pages in latex, no figures, title and abstract changed, a new section and some references adde

    Simulación Numérica del Efecto de un Mecanismo de Estratificación de Aire en un Quemador de Alta Velocidad

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    In this work, staged air combustion in a high speed burner was analyzed by mean of numerical simulation in order to determine its effects on temperature distribution and pollutant chemical species formation such as CO and NOx. The simulations were achieved using the commercial software ANSYS FLUENT as a design tool to predict the behavior of the thermal system and to establish operation conditions with or without staged air. Eddy Dissipation model was used for combustion simulation, while k - ε Realizable and Discrete Ordinates models were utilized for turbulence and radiation simulation, respectively. Results show that staged air mechanism allows better flame stabilization, combustion reactions initiation and fuel-air mixing. The CO formation was different in reaction zone and NOx emissions were not significantly influenced by the staged air.En este trabajo se analizó por medio de simulación numérica el efecto de la estratificación de aire en un quemador de alta velocidad con el fin de determinar su efecto sobre la distribución de temperatura, la estabilidad de llama y la formación de especies químicas contaminantes como CO y NOx. Las simulaciones se realizaron utilizando el software comercial ANSYS FLUENT para predecir el comportamiento del sistema con y sin uso del mecanismo de suministro de aire por etapas. En cada simulación se empleó el modelo Eddy Dissipation para la combustión, mientras que los modelos k - ε Realizable y Ordenadas Discretas fueron usados para la simulación del flujo turbulento y la radiación, respectivamente. Los resultados muestran que el uso de un mecanismo para estratificar el aire favorece la estabilización de llama, la iniciación de las reacciones de combustión y el mecanismo de mezclado. La formación de CO presentó diferencias en la zona de reacción y las emisiones de NOx no fueron significativamente influenciadas por el mecanismo de estratificación de aire
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