La proyección estereográfica y deformación conforme de métricas en la bola

La proyección estereográfica de la esfera, desde uno de sus puntos N a un plano que toca a la esfera en un punto S, diametralmente opuesto al punto N, preserva ángulos y envía circunferencias a rectas o a circunferencias. En esta conferencia, conservando sus propiedades, extenderemos la proyección estereográfica a una función f de la bola unitaria en un semiespacio s de 3 R . Usando la función f construiremos una familia de métricas planas sobre la bola euclidiana conformes con la métrica euclidiana

Techno-Economic Analysis of Rural 4th Generation Biomass District Heating

Biomass heating networks provide renewable heat using low carbon energy sources. They can be powerful tools for economy decarbonization. Heating networks can increase heating efficiency in districts and small size municipalities, using more efficient thermal generation technologies, with higher efficiencies and with more efficient emissions abatement technologies. This paper analyzes the application of a biomass fourth generation district heating, 4GDH (4th Generation Biomass District Heating), in a rural municipality. The heating network is designed to supply 77 residential buildings and eight public buildings, to replace the current individual diesel boilers and electrical heating systems. The development of the new fourth district heating generation implies the challenge of combining using low or very low temperatures in the distribution network pipes and delivery temperatures in existing facilities buildings. In this work biomass district heating designs based on third and fourth generation district heating network criteria are evaluated in terms of design conditions, operating ranges, effect of variable temperature operation, energy efficiency and investment and operating costs. The Internal Rate of Return of the different options ranges from 6.55% for a design based on the third generation network to 7.46% for a design based on the fourth generation network, with a 25 years investment horizon. The results and analyses of this work show the interest and challenges for the next low temperature DH generation for the rural area under analysis

Development of Interactive Materials by Engineering Students Using the Descartes Applets.

In a degree course such as Forestry Engineering, the general teaching objectives consist of explaining and helping students to understand the principles of Mechanics. For some time now we have encountered significant difficulties in teaching this subject due to the students' lack of motivation and to their insufficient prior preparation for the topic. If we add to this the discipline's inherent complexity and the students' preconceptions about the subject, these teaching difficulties become considerable. For this reason a series of didactic activities have been introduced sequentially in the teaching of this subject. This work describes the methodology, procedure and results for the action of developing a work project in groups using Descartes software. The results of this experiment can be considered very positive. Some of the critical preconceptions for learning the subject can be corrected, and the tutoring process in the classroom contributes to an improvement in teacherstudent communication. Since this scheme was established, the number of students taking part each academic year has increased, and this is the group with the greatest percentage of passing scores

Middle part of the Mendoza River : water table level : 1986-1996

El área de surgencia del tramo medio del río Mendoza, está caracterizada hidrogeológicamente por afloramientos de vertientes que originan arroyos. Es la zona hortícola mas importante de Mendoza (Argentina), productora de verduras durante todo el año. Se practican no menos de dos cultivos anuales, en el mismo terreno, de lechuga, espinaca, repollo, coliflor, apio, ajo, cebolla, tomate y papa. Los suelos son intrazonales, ricos en materia orgánica, con tendencia a la salinización. En profundidad hay capas de arcillas que impiden o retardan la percolación de las aguas de riego. La topografía es suavemente ondulada en el sentido O-E. Tiene depresiones con afloramiento de vertientes, abundante durante el invierno, disminuyendo en primavera y tendiendo a la estabilización en verano. Con los registros 1989/96 de una red de freatímetros se confeccionaron tres planos de niveles freáticos: • isobatas mínimas absolutas • isobatas medias • isohipsas medias. Con el primer plano se establecieron 16 419  ha  (47,3  %  del  área  de  la  red freatimétrica) con niveles freáticos entre 0 y 1 m  de  profundidad.  La  superfiecie  para igual profundidad freática, según las isobatas medias fue de 1 496 ha (4,4 % del área precitada). Con las isohipsas medias se demostró la dirección SO-NE del flujo y la influencia de los arroyos en la descarga hídrica. De los hidrogramas anuales no se observa una correlación completa entre los volú- menes derivados en dique Cipolletti y los niveles freáticos medios en el área de estudio. El hidrograma de la serie 1989/96 revela que las profundidades freáticas medias oscilan entre 1,4 y 2,1 m pudiéndose observar un desfasaje -o retardo- de tres meses entre los aportes de agua y los niveles freáticos medios. Se recomendó mitigar las disminuciones de los caudales de las perforaciones y afloramientos de arroyos y vertientes como consecuencia de la puesta en funcionamiento del Dique Potrerillos. Igualmente, concluir el saneamiento del colector Pescara para mejorar rendimientos de cultivos y ambientales.The artesian aquifer area is in the middle reach of the Mendoza river has hidrogeological characteristics causing drainage outcrops and originating brooks. This important zone of Mendoza (Argentina) gives whole year vegetables. The agriculture is intensive, with never less than two cultivations a year in the same ground, of green salad, spinach, white cabbage, cauliflower, celery, garlic, onion, tomato and potato. Soils are intrazonal, rich in organic material, with tendency to salinization. Deeper claybeds stop or slow down percolation of irrigation waters. The topography is slow, shafting from W to E producing drainage outcrops in these depressions, most importants in winter, reduced in spring and established in summer. With water table mesurements of a piezometer network during 1989/96 were plotted three water table plans: • absolute minimum equal deep level lines • middle equal deep level lines • water table contour lines. The first plan shows that the surface with water table deepness between 0 and 1 meter is 16 419 ha (47,3 % of the piezometer network). For the middle equal deep level line plan by same water level deepness surface is 1 496 ha (4,4 %) and the water table contour line plan shows a groundwater flow from SW to NE and the influence the brooks have as discharges on the waterflow. From the anual hidrographs there is no complete correlation between derived volumes in the Cipolletti dike and the middle water table levels of the area observed. From the 1989/96 hidrograph datas results that water table depths are between 1,4 and 2,1 m, showing a non coincidence or delay of three months between the water yields and the middle water table levels. It is recomended to alleviate the reduction of the flow rates of the drillings and of the outcrops in the brook system and drainage as a conse-quence of the Potrerillos dike in function. Also, it is recomendated to make progress with the sanitation of the Pescara collector to get a better cultivated and environmental yield.Fil: Ortiz Maldonado, Gonzalo. Universidad Nacional de Cuyo. Facultad de Ciencias Agrarias. Departamento de Ingeniería AgrícolaFil: Gómez, Hugo W. . Mendoza. Departamento General de Irrigació

De Flora Valentina, XV

Se comunican los hallazgos de una serie de especies de plantas vasculares detectadas en la provincia de Valencia, principalmente en la comarca del Valle de Ayora, que resultan novedosas o poco conocidas en la mismaSeveral new or rare taxa of vascular plants found in the west of the province of Valencia (E Spain) are here commente

De Flora Valentina, XVI

Several new or rare taxa of vascular plants found in the west of the Valencia region (E Spain) are here commented

Estrategias de investigación para determinar sistematicidad y generalidad de los grupos armados organizados al margen de la ley

La ley 975 de 2005, denominada ley de Justicia y Paz, adoptó procedimientos especiales con el objeto de propiciar y facilitar la reincorporación a la sociedad civil de los grupos armados al margen de la ley con miras a lograr la consecución de la paz, la verdad, la justicia y la reparación. Este proceso de desmovilización evidenció complejas estructuras de macro criminalidad, las cuales operaban en gran parte del territorio nacional, lo que llevó a que la Fiscalía General de la Nación, diseñara mecanismos especiales de investigación para poder determinar responsabilidades penales frente a la ley.Law 975 of 2005, known as the Justice and Peace law, adopted special procedures in order to encourage and facilitate the reintegration into civil society of armed groups outside the law with a view to achieving peace, truth, justice and reparation. This complex showed demobilization macro structures crime, which operated in much of the country, which led to the Attorney General's Office, to design special investigative mechanisms to determine criminal responsibility before the law