Radiactividad natural de los materiales de construcci��n. Aplicaci��n al hormig��n. Parte II. Radiaci��n interna: el gas rad��n

El presente art��culo analiza aspectos relacionados con los tipos de radiactividad natural presentes en el interior de las edificaciones, sus fuentes y sus influencias. M��s concretamente, desarrolla el estudio de la radiactividad ambiental en el interior de los espacios construidos debida a la presencia del gas rad��n, as�� como sus fuentes de origen y los niveles recomendados. Este es un art��culo que se presenta como la segunda parte de un trabajo sobre radiactividad natural en los materiales de construcci��n, cuya primera parte hace referencia a la radiaci��n externa de dichos materiales y se publica por los mismos autores, en esta misma revista. Al mismo tiempo, se realiza un recorrido por el marco normativo, tanto internacional como nacional, relativo al rad��n y a sus descendientes de vida media corta. El presente trabajo es parte de la tesis doctoral de la primera autora del mismo, Beatriz Piedecausa Garc��a, a quien el resto de autores agradece su esfuerzo para preparar el texto que ahora se publica y la autorizaci��n y las facilidades ofrecidas para acceder a su trabajo.

Alteration of natural �����Ar activity concentration in the subsurface by gas transport and water infiltration

High �����Ar activity concentration in soil gas is proposed as a key evidence for the detection of underground nuclear explosion by the Comprehensive Nuclear Test-Ban Treaty. However, such a detection is challenged by the natural background of �����Ar in the subsurface, mainly due to Ca activation by cosmic rays. A better understanding and improved capability to predict �����Ar activity concentration in the subsurface and its spatial and temporal variability is thus required. A numerical model integrating �����Ar production and transport in the subsurface is developed, including variable soil water content and water infiltration at the surface. A parameterized equation for �����Ar production in the first 15 m below the surface is studied, taking into account the major production reactions and the moderation effect of soil water content. Using sensitivity analysis and uncertainty quantification, a realistic and comprehensive probability distribution of natural �����Ar activity concentrations in soil gas is proposed, including the effects of water infiltration. Site location and soil composition are identified as the parameters allowing for a most effective reduction of the possible range of �����Ar activity concentrations. The influence of soil water content on �����Ar production is shown to be negligible to first order, while �����Ar activity concentration in soil gas and its temporal variability appear to be strongly influenced by transient water infiltration events. These results will be used as a basis for practical CTBTO concepts of operation during an OSI.

Compressed air handbook; a reference book on all phases of industrial air and gas compressors and compressed-air-powered portable tools and rock drills used by industry.

Mode of access: Internet.

Pressure vessel design; effects of pressurizing. Presented at the annual meeting of the Compressed Gas Association, New York, N. Y., January 23-24, 1950.

Cover title.

Arctic National Wildlife Refuge, Alaska : hearings before the Committee on Energy and Natural Resources, United States Senate, One hundredth Congress, first session on the report of the Secretary of the Interior to the Congress regarding oil and gas leasing on the coastal plain of the Arctic National Wildlife Refuge, Alaska.

"July 22, 1987"--Pt. 2.

National action plan for reducing greenhouse gas emissions : hearing before the Committee on Energy and Natural Resources, United States Senate, One Hundred Third Congress, first session ....

"October 28, 1993"--Pt. 2.

Caso de estudio. Gas natural en Colombia -Gas e.s.p.

La utilizaci��n del gas natural en Colombia se remonta al descubrimiento de los campos de Santander. Con excepci��n de los campos de gas libre, el gas asociado fue considerado en elpa��s como un subproducto de la explotaci��n del crudo, y era quemado en las teas (un tipo de antorcha) de los campos petroleros. Desde 1961, la conciencia sobre el valor del gas seempieza a plasmar en la legislaci��n, y es por primera vez a trav��s de la Ley 10 de 1961, que se proh��be de forma expl��cita su quema, posteriormente se ratifica mediante el decreto 1873de 1973. En 1973 se inicia la construcci��n en la Costa Atl��ntica del primer gasoducto para atender las necesidades del sector industrial para esa zona del pa��s, extendi��ndose a todos sus departamentos. Con el objeto de sustituir energ��ticos de alto costo, en 1986 se estableci�� el primer plan nacional de uso general del gas natural, llamado ��Programa de gas para el cambio��. El bajo volumen de reservas de esa ��poca y la coyuntura en que se desenvolv��an los energ��ticos, los cualesestaban subsidiados, limitaron el desarrollo de este plan. En 1990 surge una vez m��s la necesidad de crear la cultura del gas. Conel documento oficial ��Lineamientos del cambio��, se da pie para que se adelanten una serie de estudios, los cuales confirman los beneficios econ��micos que se derivar��an para el pa��s a partir de la utilizaci��n de este combustible...

Plan estrat��gico de la empresa de distribuci��n Gas Natural BAN S.A. per��odo 2008-2010

El trabajo de investigaci��n est�� centrado en la elaboraci��n del planeamiento estrat��gico para la empresa de distribuci��n de Gas Natural Buenos Aires Norte (GASBAN), ubicada en la zona norte de la provincia de Buenos Aires, Argentina, que cuenta principalmente con consumidores residenciales de bajos ingresos econ��micos. La situaci��n en la que se encuentra la empresa, estados econ��micos-financieros agonizantes, el escenario econ��mico, pol��tico y social decreciente del pa��s para los siguientes a��os y la reducci��n de ingresos por ventas y servicios, obligaban a GASBAN a dise��ar un nuevo plan estrat��gico para los siguientes 3 a��os.

An��lisis de modelos de optimizaci��n de redes de transmisi��n del gas natural con ��nfasis en el sistema colombiano

Tesis (Ingeniero(a) El��ctrico).--Universidad de La Salle. Facultad de Ingenier��a. Programa de Ingenier��a El��ctrica, 2014

Aproximando la funci��n de consumo de combustible en compresores de gas natural

En una red de transporte de gas natural, una estaci��n compresora tiene el papel primordial de incrementar la presi��n del gas para mantenerlo fluyendo en el sistema

An��lisis del sistema de seguridad y salud en el trabajo aplicado a frentes de obra de Gas Natural Cundiboyacense S.A. ESP.

79 p.

Caracterizaci��n de las empresas familiares del sector del gas natural vehicular en Bogot��

Bogot�� (Colombia): Universidad de La Salle. Facultad de Ciencias Administrativas y Contables. Programa de Administraci��n de Empresas

Brazilian Natural Fiber (jute) As Raw Material For Activated Carbon Production.

Jute fiber is the second most common natural cellulose fiber worldwide, especially in recent years, due to its excellent physical, chemical and structural properties. The objective of this paper was to investigate: the thermal degradation of in natura jute fiber, and the production and characterization of the generated activated carbon. The production consisted of carbonization of the jute fiber and activation with steam. During the activation step the amorphous carbon produced in the initial carbonization step reacted with oxidizing gas, forming new pores and opening closed pores, which enhanced the adsorptive capacity of the activated carbon. N2 gas adsorption at 77K was used in order to evaluate the effect of the carbonization and activation steps. The results of the adsorption indicate the possibility of producing a porous material with a combination of microporous and mesoporous structure, depending on the parameters used in the processes, with resulting specific surface area around 470 m2.g-1. The thermal analysis indicates that above 600��C there is no significant mass loss.

Greenhouse gas emissions from alternative futures of deforestation and agricultural management in the southern Amazon

The Brazilian Amazon is one of the most rapidly developing agricultural areas in the world and represents a potentially large future source of greenhouse gases from land clearing and subsequent agricultural management. In an integrated approach, we estimate the greenhouse gas dynamics of natural ecosystems and agricultural ecosystems after clearing in the context of a future climate. We examine scenarios of deforestation and postclearing land use to estimate the future (2006-2050) impacts on carbon dioxide (CO(2)), methane (CH(4)), and nitrous oxide (N(2)O) emissions from the agricultural frontier state of Mato Grosso, using a process-based biogeochemistry model, the Terrestrial Ecosystems Model (TEM). We estimate a net emission of greenhouse gases from Mato Grosso, ranging from 2.8 to 15.9 Pg CO(2)-equivalents (CO(2)-e) from 2006 to 2050. Deforestation is the largest source of greenhouse gas emissions over this period, but land uses following clearing account for a substantial portion (24-49%) of the net greenhouse gas budget. Due to land-cover and land-use change, there is a small foregone carbon sequestration of 0.2-0.4 Pg CO(2)-e by natural forests and cerrado between 2006 and 2050. Both deforestation and future land-use management play important roles in the net greenhouse gas emissions of this frontier, suggesting that both should be considered in emissions policies. We find that avoided deforestation remains the best strategy for minimizing future greenhouse gas emissions from Mato Grosso.

The Amazon Frontier of Land-Use Change: Croplands and Consequences for Greenhouse Gas Emissions

The Brazilian Amazon is one of the most rapidly developing agricultural frontiers in the world. The authors assess changes in cropland area and the intensification of cropping in the Brazilian agricultural frontier state of Mato Grosso using remote sensing and develop a greenhouse gas emissions budget. The most common type of intensification in this region is a shift from single-to double-cropping patterns and associated changes in management, including increased fertilization. Using the enhanced vegetation index (EVI) from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor, the authors created a green-leaf phenology for 2001-06 that was temporally smoothed with a wavelet filter. The wavelet-smoothed green-leaf phenology was analyzed to detect cropland areas and their cropping patterns. The authors document cropland extensification and double-cropping intensification validated with field data with 85% accuracy for detecting croplands and 64% and 89% accuracy for detecting single-and double-cropping patterns, respectively. The results show that croplands more than doubled from 2001 to 2006 to cover about 100 000 km(2) and that new double-cropping intensification occurred on over 20% of croplands. Variations are seen in the annual rates of extensification and double-cropping intensification. Greenhouse gas emissions are estimated for the period 2001-06 due to conversion of natural vegetation and pastures to row-crop agriculture in Mato Grosso averaged 179 Tg CO(2)-e yr(-1),over half the typical fossil fuel emissions for the country in recent years.