Influencia de la maquinaria agrícola sobre la variabilidad espacial de la compactación del suelo. Aplicación de la metodología geoestadística-fractal

El cultivo de la caña de azúcar es uno de los más importantes en muchos países del mundo. Los suelos dedicados a este cultivo son usualmente compactados por el tránsito de la maquinaria en el proceso de cosecha. El uso combinado de la geoestadística con el análisis fractal ha demostrado ser útil para el estudio de los mismos. El objetivo del trabajo fue determinar los cambios espaciales de la resistencia a la penetración del suelo debido a la influencia del tránsito de la maquinaria en el proceso de cosecha de la caña de azúcar en un Vertisol, aplicando la metodología geoestadística-fractal. La investigación se llevó a cabo en el período de cosecha 2008-2009. Se evaluó la resistencia a la penetración en dos momentos, antes y después de la cosecha. El muestreo se realizó sistemáticamente en cuadrícula y en transecto, seleccionando 144 y 100 observaciones antes y después de la cosecha, respectivamente, y 221 para el transecto en diagonal. También se determinó el contenido de humedad del suelo por el método gravimétrico, para lo que se tomaron 288 muestras aleatorias en todo el campo. Los resultados demuestran que los valores de resistencia a la penetración (RP) presentaron una distribución normal a partir de los 5 cm de profundidad, el tránsito de la maquinaria agrícola para la cosecha de la caña de azúcar provocó concentración de la variabilidad espacial a escalas inferiores a la del muestreo (el efecto pepita aumentó), un aumento del rango de correlación espacial y una redistribución de las zonas de compactación (las variaciones de los mapas de Krigeaje). También indujo anti-persistencia y anisotropía en algunas direcciones horizontales. Se observó un comportamiento irregular de (RP) verticalmente en el transecto, donde no solamente influyó la maquinaria, sino que también otros factores influyeron como: la hilera, borde de la hilera y grietas. ABSTRACT The cultivation of the cane of sugar is one of the most important in many countries of the world. The soils dedicated to this cultivation are usually compacted by the traffic of the machinery in the harvest process. The combined use of the geostatistics with the fractal analysis has demonstrated to be useful for the study of the same ones. The objective of the work was to determine the space changes from the resistance to the penetration of the floor due to the influence of the traffic of the machinery in the harvest process of harvest of the cane of sugar in a Vertisol applying the geostatistic-fractal methodology. The investigation was carried out in the period of harvest 2008-2009. The resistance to the penetration at two moments was evaluated, before and after the harvest. The sampling was realized systematically in grid and transect, selecting 144 and 100 observations before and after the harvest, respectively, and 221 for transect in diagonal. Also the soil moisture content of the ground by the gravimetric method was determined, so 288 random samples in the entire field were taken. The results shown that resistance to penetration values presented a normal distribution deeper than 5 cm before and after harvest. The transit of the agricultural machinery for sugar cane harvest concentrated the space variability at lower distances than the sampling one, reflected an increase in the nugget effect. At the same time, an increase space correlation rank and a redistribution of compaction areas were observed studying the variations in kriging maps. Another effect of the agricultural machinery transit was to induce antipersistence and anisotropy in some horizontal directions. However, in vertical direction of the longest transect an irregular behaviour was induced not only by the machinery as by another factors such as soil cracks, crop rows and allocation.

Chaotic behaviour evaluation in optical logic gates with fractal concepts

A chaotic output was obtained previously by us, from an Optical Programmable Logic Cell when a feedback is added. Some time delay is given to the feedback in order to obtain the non-linear behavior. The working conditions of such a cell is obtained from a simple diagram with fractal properties. We analyze its properties as well as the influence of time delay on the characteristics of the working diagram. A further study of the chaotic obtained signal is presented.

On the generative equations of fractal self-similarity in granular media and the related PSD models

The physical appearance of granular media suggests the existence of geometrical scale invariance. The paper discuss how this physico-empirical property can be mathematically encoded leading to different generative models: a smooth one encoded by a differential equation and another encoded by an equation coming from a measure theoretical property.

El agua en el aula: ¿cómo enseñar su nueva dimensión?

A raíz de la implementación de las Directivas Marco del Agua de la CE se han producido una serie de cambios conceptuales en el estudio del agua. Hoy en día, el agua necesita ser estudiada no sólo como agente a controlar, sino también como recurso a gestionar, como bien a valorar y como elemento básico del ecosistema a preservar. En esta nueva etapa que se abre son indispensables disciplinas también nuevas que capaciten a los técnicos encargados de esta gestión : conocimientos avanzados para entender el comportamiento no sólo de las aguas superficiales, sino también de las subterráneas, costeras y de transición, aplicaciones informáticas , nuevos procedimientos para el control de la escorrentía superficial y la conservación de suelos entre otras las nuevas técnicas de ordenación de cultivos, herramientas que permitan conocer el funcionamiento de los ecosistemas fluviales, técnicas para caracterizar y clasificar los regímenes hidrológicos, procedimientos para la obtención de series de caudales sintéticos , metodologías que permitan valorar el grado de alteración hidrológica y estrategias para la propuesta de medidas correctoras, protocolos de análisis de la calidad de los ecosistemas acuáticos, metodologías y técnicas fluviales, conocer e implementar técnicas de modelización del hábitat fluvial, estudio de los riegos de inundaciones, etc…Todo ello supone una nueva manera de entender la educación, la ingeniería y la política ambiental.

Fractal analysis of laplacian pyramidal filters applied to segmentation of soil images

The laplacian pyramid is a well-known technique for image processing in which local operators of many scales, but identical shape, serve as the basis functions. The required properties to the pyramidal filter produce a family of filters, which is unipara metrical in the case of the classical problem, when the length of the filter is 5. We pay attention to gaussian and fractal behaviour of these basis functions (or filters), and we determine the gaussian and fractal ranges in the case of single parameter ?. These fractal filters loose less energy in every step of the laplacian pyramid, and we apply this property to get threshold values for segmenting soil images, and then evaluate their porosity. Also, we evaluate our results by comparing them with the Otsu algorithm threshold values, and conclude that our algorithm produce reliable test results.

A packing computational method relating fractal particle size distribution and void fraction in granular media

The study of granular systems is of great interest to many fields of science and technology. The packing of particles affects to the physical properties of the granular system. In particular, the crucial influence of particle size distribution (PSD) on the random packing structure increase the interest in relating both, either theoretically or by computational methods. A packing computational method is developed in order to estimate the void fraction corresponding to a fractal-like particle size distribution.

La nueva dimensión del Banco Hispano Americano: los edificios de la Banca Sainz, del Crédit Lyonnais y del Banco Zaragozano

La nueva dimensión del Banco Hispano Americano: los edificios de la Banca Sainz, del Crédit Lyonnais y del Banco Zaragozano

Computer simulation of the interplay between fractal structures and surrounding heterogeneous multifractal distributions. Applications

In a large number of physical, biological and environmental processes interfaces with high irregular geometry appear separating media (phases) in which the heterogeneity of constituents is present. In this work the quantification of the interplay between irregular structures and surrounding heterogeneous distributions in the plane is made For a geometric set image and a mass distribution (measure) image supported in image, being image, the mass image gives account of the interplay between the geometric structure and the surrounding distribution. A computation method is developed for the estimation and corresponding scaling analysis of image, being image a fractal plane set of Minkowski dimension image and image a multifractal measure produced by random multiplicative cascades. The method is applied to natural and mathematical fractal structures in order to study the influence of both, the irregularity of the geometric structure and the heterogeneity of the distribution, in the scaling of image. Applications to the analysis and modeling of interplay of phases in environmental scenarios are given.

An introduction to flow and transport in fractal models of porous media: Part I

This special issue gathers together a number of recent papers on fractal geometry and its applications to the modeling of flow and transport in porous media. The aim is to provide a systematic approach for analyzing the statics and dynamics of fluids in fractal porous media by means of theory, modeling and experimentation. The topics covered include lacunarity analyses of multifractal and natural grayscale patterns, random packing's of self-similar pore/particle size distributions, Darcian and non-Darcian hydraulic flows, diffusion within fractals, models for the permeability and thermal conductivity of fractal porous media and hydrophobicity and surface erosion properties of fractal structures.

La dimensión sonora del paisaje. Herramientas, modelos y prototipos aplicados para la interpretación del paisaje sonoro pretérito

Arrancando en la definición de paisaje como construcción de un espacio virtual desde una posición referencial, la investigación constituye una inmersión en la escucha como mirada específica para llevarlo a cabo. La investigación se centra en la búsqueda de una serie de estrategias: herramientas de interpretación y modelos de análisis de la realidad que pueden interactuar con el medio espacial. Mediante el estudio del territorio a través de parámetros vinculados a las energías dinámicas existentes en el mismo, el fin es aportar una nueva lectura, una transcripción del evento sonoro generador del ser de un lugar, empleando para ello el lenguaje arquitectónico y la notación espacio-temporal. El acantilado del Pointe du Hoc se toma como primer caso de estudio para el planteamiento del análisis de la dimensión sonora del territorio, a través de la fabricación de ntermediarios espaciales, que constituirán un modelo aplicable a otros lugares cuya identidad y energía sonora formen un rasgo significativo de su existencia. PALABRAS CLAVE Paisaje sonoro, sonido, Intermediario espacial, territorio Starting in the definition of landscape as building a virtual space from a reference position, this research is an immersion in listening as specific look to carry it out. The research is focused on a number of strategies: prototypes, tools for interpretation and analysis models of reality that can interact with the space environment. By studying the area using parameters linked to existing dynamic energies in territory, the aim is to provide a new reading, a transcript of the sound event generator, employing the architectural language and space-temporary notation. The Pointe du Hoc cliff is taken as a first case study for the approach to the analysis of the sound dimension of the territory, through space intermediaries, which will be a model for other places whose sound energy is the significance of their existence. KEYWORDS Soundscape, Sound, space intermediate, territory

Fractal parameters of pore space from CT images of soils under contrasting management practices

Soil structure plays an important role in flow and transport phenomena, and a quantitative characterization of the spatial heterogeneity of the pore space geometry is beneficial for prediction of soil physical properties. Morphological features such as pore-size distribution, pore space volume or pore?solid surface can be altered by different soil management practices. Irregularity of these features and their changes can be described using fractal geometry. In this study, we focus primarily on the characterization of soil pore space as a 3D geometrical shape by fractal analysis and on the ability of fractal dimensions to differentiate between two a priori different soil structures. We analyze X-ray computed tomography (CT) images of soils samples from two nearby areas with contrasting management practices. Within these two different soil systems, samples were collected from three depths. Fractal dimensions of the pore-size distributions were different depending on soil use and averaged values also differed at each depth. Fractal dimensions of the volume and surface of the pore space were lower in the tilled soil than in the natural soil but their standard deviations were higher in the former as compared to the latter. Also, it was observed that soil use was a factor that had a statistically significant effect on fractal parameters. Fractal parameters provide useful complementary information about changes in soil structure due to changes in soil management. Read More: http://www.worldscientific.com/doi/abs/10.1142/S0218348X14400118?queryID=%24%7BresultBean.queryID%7D&

A Packing Computational Method Relating Fractal Particle Size Distribution and Void Fraction in Granular Media

The study of granular systems is of great interest to many fields of science and technology. The packing of particles affects to the physical properties of the granular system. In particular, the crucial influence of particle size distribution (PSD) on the random packing structure increase the interest in relating both, either theoretically or by computational methods. A packing computational method is developed in order to estimate the void fraction corresponding to a fractal-like particle size distribution.

El agua en el aula ¿cómo enseñar su nueva dimensión?

La Directiva Marco del Agua y la Directiva de Inundaciones han conformado una nueva manera de entender el agua en la Unión Europea. Paralelamente el panorama educativo universitario ha sido renovado con la Declaración de Bolonia y la creación del Espacio Europeo de Educación Superior. Estamos ante una oportunidad única, la Universidad ofrece la posibilidad de cambiar contenidos, métodos y procedimientos y desde Europa se formulan nuevos paradigmas en los aspectos más relevantes de la gestión del agua.

Characterization of rock joints by fractal analysis

From a physical perspective, a joint experiences fracturing processes that affect the rock at both microscopic and macroscopic levels. The result is a behaviour that follows a fractal structure. In the first place, for saw-tooth roughness profiles, the use of the triadic Koch curve appears to be adequate and by means of known correlations the JRC parameter is obtained from the angle measured on the basis of the height and length of the roughnesses. Therefore, JRC remains related to the geometric pattern that defines roughness by fractal analysis. In the second place, to characterise the geometry of irregularities with softened profiles, consequently, is proposed a characterisation of the fractal dimension of the joints with a circumference arc generator that is dependent on an average contact angle with regard to the mid-plane. The correlation between the JRC and the fractal dimension of the model is established with a defined statistical ratio.

Dimensión territorial de los sistemas alimentarios locales. El caso de Madrid

Una de las características definitorias del sistema urbano contemporáneo es su desterritorialización, es decir, su adopción de un modelo de desarrollo que se da al margen del territorio concreto que lo sustenta y de los recursos biofísicos y culturales existentes en él. Dicha desterritorialización es posible gracias al uso intensivo de energía que ha permitido ampliar hasta la escala global los flujos del metabolismo urbano. De este modo se han roto las relaciones de proximidad urbano-rurales, y se ha aumentado la dependencia de recursos externos. Entre las diferentes manifestaciones de esta desterritorialización se encuentra la organización del sistema alimentario, que en la actualidad responde a un modelo globalizado, en el que la distancia entre producción y consumo ha aumentado a costa de incrementar el gasto energético en transporte y conservación de alimentos. Este distanciamento físico va acompañado también de un distanciamiento social e identario, con la hegemonía de un modelo agroindustrial que no respeta los paisajes, las prácticas agrícolas, los conocimientos tradicionales ni las variedades genéticas locales. Tanto el modelo territorial como el alimentario son altamente vulnerables ante crisis externas que pueden alterar su funcionamiento. El enfoque (bio)regionalista desde el mismo inicio de la ciudad industrial hasta nuestros días ha propuesto un modelo de ordenación territorial alternativo, adaptado a las condiciones locales y basado en la proximidad, que dotaría al sistema territorial de mayor resiliencia y sostenibilidad. Para confirmar este presupuesto y evaluar la capacidad de reterritorialización alimentaria se ha desarrollado una metodología que aborda el estudio del sistema territorial como socioecosistema complejo, en el que se distinguen componentes de tipo social, construido y biofísico, que se encuentran interrelacionados. La historia de cambios en la organización del sistema, su estado actual y su capacidad de reorganizarse en estados alternativos son las bases de dicha evaluación. Esta metodología se aplica a la Comunidad de Madrid con el fin de describir su sistema territorial desde el punto de vista del abastecimiento alimentario y evaluar su capacidad de reterritorialización. ABSTRACT Deterritorialization is one of the defining characteristics of the contemporary urban system. This means that its development model is designed ignoring the attributes of the specific region in which is located, and the biophysical and cultural resources therein. Such territorialization is possible due to the intensive energy consumption that allows expanding to a global scale the flows of urban metabolism. This way, urban-rural linkages have been broken, increasing dependency on external resources. The modern food system is among the clearest expressions of a deterritorialized model. In a globalized food system, increasing distances between production and consumption spaces are possible through energy-intensive transport and preservation activities. Physical distanciation goes hand in hand with social disconnection and loss of identity, due to a hegemonic agro-industrial model that does not respect local landscapes, agricultural practices, traditional knowledge or genetic varieties. Both the regional and the food systems are highly vulnerable to external shocks that may affect their functions. The bioregionalist approach has proposed, since the industrial city until today, an alternative model, adapted to local conditions and rooted on proximity, which provides a sustainable and resilient regional planning and management. To confirm this assumption and assess the food reterritorialisation capacity, a methodology has been developed that address the regional system as a complex social-ecosystem, in which interrelated social, built and biophysical subsystems are included. Assessment is based in the analysis of regimes shifts in the history of the system, and in the description of its current and alternative states. This methodology is applied to the administrative region of Madrid in order to describe its regional food system and assess its reterritorialization capacity.