Approximation to earth material from international normative

For centuries, earth has been used as a construction material. Nevertheless, the normative in this matter is very scattered, and the most developed countries, to carry out a construction with this material implies a variety of technical and legal problems. In this paper we review, in an international level, the normative panorama about earth constructions. It analyzes ninety one standards and regulations of countries all around the five continents. These standards represent the state of art that normalizes the earth as a construction material. In this research we analyze the international standards to earth construction, focusing on durability test (spray and drip erosion tests). It analyzes the differences between methods of test. Also we show all results about these tests in two types of compressed earth block.

New selective earth faults only current directional method for isolated neutral systems

In order to achieve total selectivity at electrical distribution networks it is of great importance to analyze the defect currents at ungrounded power systems. This information will help to grant selectivity at electrical distribution networks ensuring that only the defect line or feeder is removed from service. In the present work a new selective and directional protection method for ungrounded power systems is evaluated. The new method measures only defect currents to detect earth faults and works with a directional criterion to determine the line under faulty conditions. The main contribution of this new technique is that it can detect earth faults in outgoing lines at any type of substation avoiding the possible mismatch of traditional directional earth fault relays. This detection technique is based on the comparison of the direction of a reference current to the direction of all earth fault capacitive currents at all the feeders connected to the same bus bars. This new method has been validated through computer simulations. The results for the different cases studied are remarkable, proving total validity and usefulness of the new method.

Rammed earth walls in the late middle age castles in the actual province of Soria, Spain

This paper analyzed the building techniques based in the use of rammed earth in the Late Medieval fortifications in the province of Soria, Spain. The manorial castles of Serón de Nágima and Yanguas were built completely with rammed earth. However, these techinques are different. Through the study of the constructive signals, we can reconstruct the constructive process and made an hypothesis of the auxiliary scaffolding necessary for the construction. After, other four cases in which there is presence of rammed earth are described: Ágreda, Arcos de Jalón, Caracena and the tower of Martín González or castle of La Raya (the Border). Rammed earth is used in some secondary architectural elements and also as a filling of the masonry walls, but somtimes there are ancient rammed earth walls overlaid with stone masonry.

Earth Delivery of a Small NEO with an Ion Beam Shepherd

The possibility of capturing a small Near Earth Asteroid (NEA) and deliver it to the vicinity of the Earth has been recently explored by different authors. The key advantage would be to allow a cheap and quick access to the NEA for science, resource utilization and other purposes. Among the different challenges related to this operation stands the difficulty of robotically capturing the object, whose composition and dynamical state could be problematic. In order to simplify the capture operation we propose the use of a collimated ion beam ejected from a hovering spacecraft in order to maneuver the object without direct physical contact. The feasibility of a possible asteroid retrieval mission is evaluated.

Earth Architecture and Construction in the colonial archaeological site of Piura la Vieja, La Matanza (Piura, Perú)

Ponencia en el congreso internacional RESTAPIA 2012 que recoge los resultados de los trabajos de investigación realizados en el yacimiento arqueológico colonial de Piura la Vieja, La Matanza (Piura, Perú).

Analysis of bare-tether systems for deorbiting low-earth-orbit satellites

Performances, design criteria, and system mass of bare tethers for satellite deorbiting missions are analyzed. Orbital conditions and tether cross section define a tether length, such that 1) shorter tethers are electron collecting practically in their whole extension and 2) longer tethers collect practically the short-circuit current in a fixed segment length. Long tethers have a higher drag efficiency (defined as the drag force vs the tether mass) and are better adapted to adverse plasma densities. Dragging efficiency and mission-related costs are used to define design criteria for tether geometry. A comparative analysis with electric thrusters shows that bare tethers have much lower costs for low- and midinclination orbits and remain an attractive option up to 70 deg.

Integrating geographical information in the Linked Digital Earth

Many progresses have been made since the Digital Earth notion was envisioned thirteen years ago. However, the mechanism for integrating geographic information into the Digital Earth is still quite limited. In this context, we have developed a process to generate, integrate and publish geospatial Linked Data from several Spanish National data-sets. These data-sets are related to four Infrastructure for Spatial Information in the European Community (INSPIRE) themes, specifically with Administrative units, Hydrography, Statistical units, and Meteorology. Our main goal is to combine different sources (heterogeneous, multidisciplinary, multitemporal, multiresolution, and multilingual) using Linked Data principles. This goal allows the overcoming of current problems of information integration and driving geographical information toward the next decade scenario, that is, ?Linked Digital Earth.?

Diseño y ensayos en tierra de paneles solares para un satélite de órbita baja = Design and testing procedures of a Low Earth Orbit (LEO) satellite solar panels

Debido al reciente incremento de conflictos en el mundo árabe y dado el interés nacional de España en dicha zona, se propone en este proyecto un estudio inicial para el diseño y desarrollo de un microsatélite que ayude al gobierno de España a mantener esa zona bajo observación constante. En el presente trabajo se abarcan todos los subsistemas del satélite, haciéndose un estudio más detallado del subsistema de potencia

Diseño del sistema de potencia para un satélite de órbita baja(LEO) = Design of a Low Earth Orbit (LEO) satellite power subsystem

Este documento contiene el proceso de prediseño y cálculo de un satélite de observación terrestre mediante imágenes fotográficas. El principal objetivo del proyecto es el diseño detallado del subsistema de potencia del satélite y a validación de un modelo de funcionamiento del sistema de potencia de las placas solares que alimentan al mismo y mediante la herramienta Simulink. La primera parte consiste en un diseño breve de los subsistemas y parámetros más importantes del satélite tales como el Sistema de Control de Actitud, Sistema de Control Térmico y Sistema de Comunicaciones, además de la estructura del satélite, la órbita en la que se encontrará, el lanzador que se usará para situarlo en órbita y la cámara que llevara a bordo para la captación de imágenes. La segunda parte trata del diseño del subsistema de potencia de una manera más detallada y de su simulación mediante una herramienta diseñada en el programa MATLAB con la herramienta Simulink. Se pretende usar la herramienta para simular el comportamiento del subsistema de potencia de un satélite conocido que será el UPMSat-2.

Diseño y ensayos en tierra de las baterías para un satélite de órbita baja = Design and testing procedures of a Low Earth Orbit (LEO) satellite battery

Este proyecto consiste en el estudio y dimensionado inicial del sistema de potencia de un satélite de observación, que sirva de ayuda a otros sistemas de mayor precisión a la hora de detectar posibles terremotos y actividad volcánica mediante el análisis de señales electromagnéticas presentes en la ionosfera. Para ello el satélite incorpora, entre otros elementos sensores eléctricos, un analizador de plasma, y un detector de partículas. Con esta instrumentación se pretenden detectar los cambios que se producen en el campo electromagnético terrestre como consecuencia del movimiento de las placas tectónicas, y descubrir así las posibles anomalías que preceden a un seísmo. Para no sobrepasar el presupuesto con el que se ha ideado el proyecto se utilizarán sistemas que permitan la lectura de datos de la forma más simple, pudiendo ocurrir que los datos recogidos no se transmitan al control de Tierra en tiempo real, impidiendo a los científicos analizar los datos recogidos hasta unos días después, de ahí que este satélite experimental deba emplearse, en principio, como apoyo a programas de detención de terremotos más sofisticados y con mayores medios técnicos. Evidentemente, con este sistema también se podrán recoger datos tras los seísmos y examinarlos posteriormente. La órbita del satélite será una órbita LEO (Low Earth Orbit) de una altitud aproximada de 670 Km, estimándose el tiempo de vida del satélite en 5 años. Intentando emplear la mayor parte de los recursos económicos en el equipamiento científico, la estructura será la más simple posible, esto es, un paralelepípedo de dimensiones compactas con un peso aproximado de 185 kg, contando con paneles solares desplegables y en su interior con baterías que proporcionarán potencia al satélite durante la fase de lanzamiento y en momentos concretos.

Diseño y ensayos en tierra de paneles solares y baterías para un satélite de órbita baja = Design and testing procedures of a Low Earth Orbit (LEO) satellite power subsystem (solar panels and battery)

Las principal conclusión que se puede obtener tras el estudio es que el satélite, tal y como se ha tenido en cuenta, es perfectamente funcional desde el punto de vista eléctrico. Por la parte de la generación de potencia, los paneles son capaces de ofreces una cantidad tal como para que aproximadamente la mitad (en el caso de funcionamiento normal) de esta potencia sea destinada a la carga útil. Además, incluso en los modos de fallo definidos, el valor de potencia dedicada a la carga útil, es suficientemente alta como para que merezca la pena mantener el satélite operativo. Respecto de las baterías, se puede observar por su comportamiento que están, sobredimensionadas y por ello actúan como un elemento regulador del sistema completo, ya que tiene un amplio margen de trabajo por el cual se puede modificar el funcionamiento general. Y esto se demuestra no sólo en cuanto al estado de carga, que para el perfil de consumo constante y el de cuatro pulsos de 120 W por día se mantiene siempre por encima del 99%, si no también en términos de charging rate, el cual se está siempre dentro de los límites establecidos por el fabricante, asegurando una vida operativa acorde con la nominal. Por último, sobre el propio método de simulación se puede extraer que aun no siendo la mejor plataforma donde estudiar estos comportamientos. Presenta el inconveniente de que, en ciertas partes, restringe la flexibilidad a la hora de cambiar múltiples condiciones al mismo tiempo, pero a cambio permite un estudio bastante amplio con un requisito de conocimientos y de complejidad bajo, de manera que habilita a cualquier estudiante a llevar a cabo estudios similares.

Dynamic earth pressures against a retaining wall caused by Rayleigh waves

An approximate procedure for studying harmonic soil-structure interaction problems is presented. The presence of Rayleigh waves is considered and the resulting governing equations of the dynamic soil-structure system are solved in the time domain. With this method the transient and steady states of a vibratory motion and also the nonlinear behaviour of the soil can be studied. As an example, the dynamic earth pressure against a rigid retaining wall is investigated. The loads are assumed to be harmonic Rayleigh waves with both static and dynamic surface surcharges. The dependence of the results on the excitation frequency is shown.

Effect of rare earth additions on the critical resolved shear stresses of magnesium alloys

An inverse optimization strategy based on crystal plasticity finite element simulations of polycrystals was used to obtain the critical resolved shear stresses of two Mg?1%Mn alloys containing neodymium from macroscopic experimental data. It was found that, with respect to pure Mg, the presence of Nd increases the CRSSbasal, CRSStwinning, and the CRSSbasal/CRSStwinning ratio and decreases the CRSSnon-basal/CRSStwinning ratio. Additions of neodymium as high as 1 wt% result in similar CRSSs values for all deformation modes and, thus, in an isotropic yielding behavior.

Rocks are human beings: researching the humanizing metaphor in earth science scientific texts

This paper describes a corpus-based analysis of the humanizing metaphor and supports that constitutive metaphor in science and technology may be highly metaphorical and active. The study, grounded in Lakoff’s Theory of Metaphor and in Langacker’s relational networks, consists of two phases: firstly, Earth Science metaphorical terms were extracted from databases and dictionaries and, then, contextualized by means of the “Wordsmith” tool in a digitalized corpus created to establish their productivity. Secondly, the terms were classified to disclose the main conceptual metaphors underlying them; then, the mappings and the relational networks of the metaphor were described. Results confirm the systematicity and productivity of the metaphor in this field, show evidence that metaphoricity of scientific terms is gradable, and support that Earth Science metaphors are not only created in terms of their concrete salient properties and attributes, but also on abstract human anthropocentric projections.

Seismic soil-interaction on earth retaining structures. Performance-based seismic design of a Retaining Wall

The design of containment walls suffering seismic loads traditionally has been realized with methods based on pseudoanalitic procedures such as Mononobe- Okabe's method, which it has led in certain occasions to insecure designs, that they have produced the ruin of many containment walls suffering the action of an earthquake. A method is proposed in this papers for the design of containment walls in different soils, suffering to the action of an earthquake, based on the Performance-Based Seismic Design.