42 resultados para Underground reservoirs

em Consorci de Serveis Universitaris de Catalunya (CSUC), Spain


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Based on the Ahumada et al. (2007, Review of Income and Wealth) critique we revise existing estimates of the size of the German underground economy. Among other things, it turns out that most of these estimates are untenable and that the tax pressure induced size of the German underground economy may be much lower than previously thought. To this extent, German policy and law makers have been misguided during the last three decades. Therefore, we introduce the Modified-Cash-Deposit-Ratio (MCDR) approach, which is not subject to the recent critique and apply it to Germany for the period 1960 to 2008. JEL: O17, Q41, C22, Keywords: underground economy, shadow economy, cash-depositratio, currency demand approach, MIMIC approach

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Coulomb suppression of shot noise in a ballistic diode connected to degenerate ideal contacts is analyzed in terms of the correlations taking place between current fluctuations due to carriers injected with different energies. By using Monte Carlo simulations we show that at low frequencies the origin of Coulomb suppression can be traced back to the negative correlations existing between electrons injected with an energy close to that of the potential barrier present in the diode active region and all other carriers injected with higher energies. Correlations between electrons with energy above the potential barrier with the rest of electrons are found to influence significantly the spectra at high frequency in the cutoff region.

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A summary of the results from the study of benthos of lakes and reservoirs in Spain is provided, with a list of the species found to date. Spanish natural lakes are smaller than European lakes; the largest is Lake Sanabria, of glacial origin, which is 3 Km long and half a kilorneter wide. Many are very small and situated in the mountains; more than 200 hundred have been recorded in Spain, but only in Lake Sanabria and Lake Banyoles have the benthos been studied. Lake Sanabria is a cold oligotrophic, monomictic lake with oxygen always present in the deepest zones. Its fauna is similar to that of other central European lakes, with Mici.opsectra c.orztractu (a chironomid) as the dominan1 species. Lake Banyoles is a karstic, monomictic and multibasin lake; despite the low primary productivity, due to the abundante of sulphate in the water, the allochthonous inflow of organic matter and the inflow of water from bottom springs, the profunda1 environinent is very stressing for benthic fauna. Very low oxygen concentrations and high sulphide content in the water and sediments dueto meromixis mean that only the larva of the dipteran Chaohoi.lcs flai7icans was present in one of the 5 basins of the lake. In other basins, when oxygen is available (no meromixis), the fauna is similar to that of tlie inineralized lakes of the Aegean region and some lakes in central Italia. On the other hand, preliminary data from the Pyrenean lakes and from Sierra Nevada ponds reveal no differences with northern cold lakes. Tlie largest lakes in Spain are the reservoirs. There are nearly 1000 and data are available on 100 of them, including the kargest. In addition to oxygen and sulphide content in the bottom waters, water level fluctuation and high sedimentation rates are disturbance factors that prevented the organization of the community. Allochthonous inputs of organic matter are also an important factor both in the reservoirs and also in the small, oligotrophic lakes like Banyoles and Sanabria. As a result the meiofaunal loop is very important in many of the Spanish water bodies . For this reason the natural lakes and reservoirs of Spain are dominated by Oligochaeta, small crustaceans and the microcarnivore chironomids (such as Procladi~ls, Cladopelma and Mi(,rnc.hil-onnmus) that feed on these meoifaunal elements. The phytophagous chironomids, like Chironomus, are only abundan1 in the shallow areas of mesotrophic and eutrophic reservoirs. This situation makes it difficult to apply the typological system of SAETHER which predicts with some confidence only the benthic communities of Spanish natural lakes above 1500 m in the Pyrenees or the ponds above 2000 m in Sierra Nevada mountains. Higher temperatures (which originate a longer stratification period), the presence of sulphate in the waters of the eastern part of Spain and high inputs of sediments and allochthonous organic matter seem to be the factors that originated the differences between the benthic profunda1 faunas of Spanish lakes and reservoirs and those of the temperate lakes of north and central Europe.

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One of the most popular options for promoting public transport use is the provision of an integrated and high quality public transport system. This was the strategy adopted by the regional government in Madrid in 1986 and since then public transport patronage has increased by more than 50%. This paper has two objectives. The first is to identify the factors underlying the significant increase in the demand for public transport in Madrid. To do this we estimate an aggregate demand function for bus and underground trips, which allows us to obtain the demand elasticities with respect to the main attributes of public transport services and also to calculate the long-term impact of changes in those explanatory variables on patronage. The second objective is to evaluate the impact on revenue derived from the introduction of the travel card scheme, and to discuss the consequences on revenue of changes in the relative fare levels of different types of ticket without substantially affecting patronage. This latter issue is addressed by estimating a matrix of own and cross-price elasticities for different ticket types.

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Report for the scientific sojourn carried out in the International Center for Numerical Methods in Engineering (CIMNE) –state agency – from February until November 2007. The work within the project Technology innovation in underground construction can be grouped into the following tasks: development of the software for modelling underground excavation based on the discrete element method - the numerical algorithms have been implemented in the computer programs and applied to simulation of excavation using roadheaders and TBM-s -; coupling of the discrete element method with the finite element method; development of the numerical model of rock cutting taking into account of wear of rock cutting tools -this work considers a very important factor influencing effectiveness of underground works -.

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L’elevat consum energètic de les societats actuals, així com la impossibilitat de sostenir-lo a llarg termini implica la cerca de noves fonts d’energia. D’aquesta manera, en el camp de la climatització residencial, l’energia geotèrmica de molt baixa entalpia es posiciona com una alternativa als recursos energètics actuals. Així, els primers metres de subsòl presenten una temperatura adequada per al seu aprofitament calorífic, mitjançant els sistemes geotèrmics de bomba de calor. Si bé a nivell energètic, són sistemes, intrínsecament, molt eficients, el seu rendiment pot patir importants variacions davant dels canvis en les condicions del medi geològic i hidrogeològic. Especialment, els col·lectors de calor verticals, treballen, amb freqüència, en el si de les formacions hidrogeològiques. En aquest sentit, els canvis del nivell hidràulic i de la temperatura de l’aigua de l’aqüífer es manifesten amb variacions de la conductivitat tèrmica equivalent i del flux subterrani d’aigua, que alhora, aquestes, es tradueixen en alteracions del flux subterrani de calor. Davant d’aquest fet, l’avaluació quantitativa de l’efecte d’aquestes fluctuacions que es presenta en aquest treball mostra petites variacions del nivell hidràulic i de la temperatura de l’aigua comporten canvis molt notables en l’eficiència dels sistemes verticals de bomba de calor geotèrmica.

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Aquest TFC consisteix en la creació d'un magatzem de dades que automatitzi la recollida de dades de l'estat dels embassaments de la Confederació Hidrogràfica Nord-Est mitjançant processos ETL, per posteriorment tractar aquestes dades amb processos PL/SQL amb l'objectiu de poder explotar aquestes dades mitjançant eines de Business Intelligence.

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Treball final de carrera que consisteix en la construcció d'un magatzem de dades o Data Warehouse, per tal de donar solució a la obtenció d'una sèrie d'informes destinats a La Confederació Hidrogràfica Nord-est (CHNE) amb l'objectiu de poder analitzar i controlar l'estat dels embassaments dins el seu abast geogràfic.

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L' objectiu fonamental d’aquest article és aprofundir en les implicacions socials i territorials que té la realització d’una gran infraestructura hidràulica com és un embassament. Aprofitant que l’Alt Empordà compta amb una de les dues úniques grans obres d’aquesta tipologia existents a totes les comarques gironines, s’ha pres com a cas pràctic d’estudi l’embassament de Boadella. A l’article s’analitzen quins van ser els antecedents que conduïren a la seva construcció i quins van ser els efectes directes que va tenir sobre el lloc de realització. Més al marge es deixaran les seves conseqüències a la plana i al litoral altempordanesos. Es farà una radiografia sobre com era l’espai que quedà ocupat per les aigües i el seu poblament i com va repercutir el projecte a sobre d’ells. Tot plegat, sense perdre de vista els contextos històric i geogràfic que envoltaren la seva execució

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Prenent com a exemple el cas de l'embassament de Boadella, al curs del riu Muga, es fa una breu descripció dels llargs antecedents que portaren a la realització d'aquesta obra i delsseus efectes sobre l'espai on fou aixecada

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This paper focus on the problem of locating single-phase faults in mixed distribution electric systems, with overhead lines and underground cables, using voltage and current measurements at the sending-end and sequence model of the network. Since calculating series impedance for underground cables is not as simple as in the case of overhead lines, the paper proposes a methodology to obtain an estimation of zero-sequence impedance of underground cables starting from previous single-faults occurred in the system, in which an electric arc occurred at the fault location. For this reason, the signal is previously pretreated to eliminate its peaks voltage and the analysis can be done working with a signal as close as a sinus wave as possible

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The chemical composition of sediments and rocks, as well as their distribution at theMartian surface, represent a long term archive of processes, which have formed theplanetary surface. A survey of chemical compositions by means of Compositional DataAnalysis represents a valuable tool to extract direct evidence for weathering processesand allows to quantify weathering and sedimentation rates. clr-biplot techniques areapplied for visualization of chemical relationships across the surface (“chemical maps”).The variability among individual suites of data is further analyzed by means of clr-PCA,in order to extract chemical alteration vectors between fresh rocks and their crusts andfor an assessment of different source reservoirs accessible to soil formation. Bothtechniques are applied to elucidate the influence of remote weathering by combinedanalysis of several soil forming branches. Vector analysis in the Simplex provides theopportunity to study atmosphere surface interactions, including the role andcomposition of volcanic gases

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Nanomotors are nanoscale devices capable of converting energy into movement and forces. Among them, self-propelled nanomotors offer considerable promise for developing new and novel bioanalytical and biosensing strategies based on the direct isolation of target biomolecules or changes in their movement in the presence of target analytes. The mainachievements of this project consists on the development of receptor-functionalized nanomotors that offer direct and rapid target detection, isolation and transport from raw biological samples without preparatory and washing steps. For example, microtube engines functionalized with aptamer, antibody, lectin and enzymes receptors were used for the direct isolation of analytes of biomedical interest, including proteins and whole cells, among others. A target protein was also isolated from a complex sample by using an antigen-functionalized microengine navigating into the reservoirs of a lab-on-a-chip device. The new nanomotorbased target biomarkers detection strategy not only offers highly sensitive, rapid, simple and low cost alternative for the isolation and transport of target molecules, but also represents a new dimension of analytical information based on motion. The recognition events can be easily visualized by optical microscope (without any sophisticated analytical instrument) to reveal the target presence and concentration. The use of artificial nanomachines has shown not only to be useful for (bio)recognition and (bio)transport but also for detection of environmental contamination and remediation. In this context, micromotors modified with superhydrophobic layer demonstrated that effectively interacted, captured, transported and removed oil droplets from oil contaminated samples. Finally, a unique micromotor-based strategy for water-quality testing, that mimics live-fish water-quality testing, based on changes in the propulsion behavior of artificial biocatalytic microswimmers in the presence of aquatic pollutants was also developed. The attractive features of the new micromachine-based target isolation and signal transduction protocols developed in this project offer numerous potential applications in biomedical diagnostics, environmental monitoring, and forensic analysis.

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En el següent estudi s’analitza en profunditat el cinema de Philippe Garrel a través dels paràmetres fotogràfics de la seva obra. Centrat fonamentalment en les primeres pel∙lícules de la seva trajectòria underground –de Le Révélateur (1968) a L’Enfant secret (1979)‐ aquesta recerca s’articula al voltant de la repercussió simbòlica, plàstica i narrativa dels usos lumínics, definits com la gramàtica de la llum i de l’ombra. La memòria presenta, en primer lloc, la llum com a essència reveladora, abordant el paradigma solar, les fonts de llum artificials –els canelobres i les làmpades‐ i la plasticitat blanca derivada d’una sobreexposició lluminosa. En segon lloc, s’introdueix el rol de la ombra com a contrapunt fotogràfic de natura englotidora per, finalment, exposar la dualitat visual interactiva del blanc i negre així com la dimensió física de la matèria pel∙licular.