949 resultados para Circuit of rock platense


Relevância:

100.00% 100.00%

Publicador:

Resumo:

This text analyzes the speeches of a group of cultural mediators working in Madrid in public and private institutions of arts. The group was organized as part of the activities of the European Project Divercity: Diving into Diversity in Museums and the City of the Complutense University in March 2015. The aim of the interview was to unravel what they mean by diversity in the profession, and analyze the contradictions and objectives professions that arise in this new field of work.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Laser scanning is a terrestrial laser-imaging system that creates highly accurate three-dimensional images of objects for use in standard computer-aided design software packages. This report describes results of a pilot study to investigate the use of laser scanning for transportation applications in Iowa. After an initial training period on the use of the scanner and Cyclone software, pilot tests were performed on the following projects: intersection and railroad bridge for training purposes; section of highway to determine elevation accuracy and pair of bridges to determine level of detail that can be captured; new concrete pavement to determine smoothness; bridge beams to determine camber for deck-loading calculations; stockpile to determine volume; and borrow pit to determine volume. Results show that it is possible to obtain 2-6 mm precision with the laser scanner as claimed by the manufacturer compared to approximately one-inch precision with aerial photogrammetry using a helicopter. A cost comparison between helicopter photogrammetry and laser scanning showed that laser scanning was approximately 30 percent higher in cost depending on assumptions. Laser scanning can become more competitive to helicopter photogrammetry by elevating the scanner on a boom truck and capturing both sides of a divided roadway at the same time. Two- and three-dimensional drawings were created in MicroStation for one of the scanned highway bridges. It was demonstrated that it is possible to create such drawings within the accuracy of this technology. It was discovered that a significant amount of time is necessary to convert point cloud images into drawings. As this technology matures, this task should become less time consuming. It appears that laser scanning technology does indeed have a place in the Iowa Department of Transportation design and construction toolbox. Based on results from this study, laser scanning can be used cost effectively for preliminary surveys to develop TIN meshes of roadway surfaces. It also appears that this technique can be used quite effectively to measure bridge beam camber in a safer and quicker fashion compared to conventional approaches. Volume calculations are also possible using laser scanning. It seems that measuring quantities of rock could be an area where this technology would be quite beneficial since accuracy is more important with this material compared to soil. Other applications for laser scanning could include developing as-built drawings of historical structures such as the bridges of Madison County. This technology could also be useful where safety is a concern such as accurately measuring the surface of a highway active with traffic or scanning the underside of a bridge damaged by a truck. It is recommended that the Iowa Department of Transportation initially rent the scanner when it is needed and purchase the software. With time, it may be cost justifiable to purchase the scanner as well. Laser scanning consultants can be hired as well but at a higher cost.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Les spirales sont des appareils de séparation gravimétrique principalement utilisés dans l’industrie du traitement du minerai de fer. La classification des particules dans la pulpe s’effectue lors de la descente dans les spires en fonction de leur taille et leur densité, des conditions d’opération et de la géométrie de la spirale. L’effet des conditions d’opération (pourcentage solide, débit d’alimentation et débit d’eau de lavage) est évalué sur la performance des spirales en utilisant une spirale WW6E installée à COREM pour traiter un minerai de fer de ArcelorMittal, Québec. Les résultats montrent l’effet dominant du débit de l’eau de lavage et son impact majeur sur les particules grossières. Un circuit fermé de trois spirales parallèles avec 3, 5 et 7 tours est utilisé afin d’évaluer l’influence du nombre de tours. Les résultats préliminaires indiquent que la spirale trois tours fonctionne bien pour le nettoyage tandis que la 7 tour est robuste pour l’ébauchage et l’épuisage.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Topography is often thought as exclusively linked to mountain ranges formed by plates collision. It is now, however, known that apart from compression, uplift and denudation of rocks may be triggered by rifting, like it happens at elevated passive margins, and away from plate boundaries by both intra-plate stress causing reactivation of older structures, and by epeirogenic movements driven by mantle dynamics and initiating long-wavelength uplift. In the Cenozoic, central west Britain and other parts of the North Atlantic margins experienced multiple episodes of rock uplift and denudation that have been variable both at spatial and temporal scales. The origin of topography in central west Britain is enigmatic, and because of its location, it may be related to any of the processes mentioned above. In this study, three low temperature thermochronometers, the apatite fission track (AFT) and apatite and zircon (U-Th-Sm)/He (AHe and ZHe, respectively) methods were used to establish the rock cooling history from 200◦C to 30◦C. The samples were collected from the intrusive rocks in the high elevation, high relief regions of the Lake District (NW England), southern Scotland and northern Wales. AFT ages from the region are youngest (55–70 Ma) in the Lake District and increase northwards into southern Scotland and southwards in north Wales (>200 Ma). AHe and ZHe ages show no systematic pattern; the former range from 50 to 80 Ma and the latter tend to record the post-emplacement cooling of the intrusions (200–400 Ma). The complex, multi-thermochronometric inverse modelling suggests a ubiquitous, rapid Late Cretaceous/early Palaeogene cooling event that is particularly marked in Lake District and Criffell. The timing and rate of cooling in southern Scotland and in northern Wales is poorly resolved as the amount of cooling was less than 60◦C. The Lake District plutons were at >110◦C prior to the early Palaeogene; cooling due to a combined effect of high heat flow, from the heat producing granite batholith, and the blanketing effect of the overlying low conductivity Late Mesozoic limestones and mudstones. Modelling of the heat transfer suggests that this combination produced an elevated geothermal gradient within the sedimentary rocks (50–70◦C/km) that was about two times higher than at the present day. Inverse modelling of the AFT and AHe data taking the crustal structure into consideration suggests that denudation was the highest, 2.0–2.5 km, in the coastal areas of the Lake District and southern Scotland, gradually decreasing to less than 1 km in the northern Southern Uplands and northern Wales. Both the rift-related uplift and the intra-plate compression poorly correlate with the timing, location and spatial distribution of the early Palaeogene denudation. The pattern of early Palaeogene denudation correlates with the thickness of magmatic underplating, if the changes of mean topography, Late Cretaceous water depth and eroded rock density are taken into consideration. However, the uplift due to underplating alone cannot fully justify the total early Palaeogene denudation. The amount that is not ex- plained by underplating is, however, roughly spatially constant across the study area and can be referred to the transient thermal uplift induced by the mantle plume arrival. No other mechanisms are required to explain the observed pattern of denudation. The onset of denudation across the region is not uniform. Denudation started at 70–75 Ma in the central part of the Lake District whereas the coastal areas the rapid erosion appears to have initiated later (65–60 Ma). This is ~10 Ma earlier than the first vol- canic manifestation of the proto-Iceland plume and favours the hypothesis of the short period of plume incubation below the lithosphere before the volcanism. In most of the localities, the rocks had cooled to temperatures lower than 30◦C by the end of the Palaeogene, suggesting that the total Neogene denudation was, at a maximum, several hundreds of metres. Rapid cooling in the last 3 million years is resolved in some places in southern Scotland, where it could be explained by glacial erosion and post-glacial isostatic uplift.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

VESPA was a successful 25 day research cruise on R/V l'Atalante that took place in May and June 2015. The main aim was to acquire new rock samples from extinct volcanoes on the Norfolk, Loyalty and Three Kings ridges, which connect New Caledonia and New Zealand. This was in order to test various hypotheses of Late Cretaceous-Miocene SW Pacific tectonic development relating to (i) nature and duration of magmatism on the ridges; (ii) timing of subduction initiation east of northern Zealandia; (iii) postulated subduction polarity changes. A total of 3400 km of 'sismique rapide' shallow reflection seismic data were acquired and processed onboard. The seismic lines provided a very useful structural-stratigraphic framework for the rock dredging. Combined with multibeam bathymetry data they allowed intelligent targeting of acoustic basement (lavas) and specific seismic reflectors (sedimentary strata) on rocky slopes and fault scarps. Different stratigraphic levels of the Loyalty and Three Kings Ridge volcanic piles were sampled by dredging at different water depths on the Cook Fracture Zone and Cagou Trough fault scarps. By the end of the cruise, 43 dredges had been attempted and 36 of them yielded igneous or sedimentary rocks potentially useful to the VESPA project. Onboard use of a portable X-ray fluorescence unit confirmed the presence of intraplate (but no arc) volcanoes on the Norfolk Ridge and presence of arc, intraplate and shoshonitic volcanoes on the Loyalty and Three Kings Ridges. A total of 770 kg of rock was retained for post-cruise analysis in New Caledonia, France and New Zealand. Future work will include micropaleontological dating of sedimentary rocks, U-Pb and Ar-Ar isotopic dating of igneous rocks, and whole rock geochemical and tracer isotope analyses. We are optimistic that many of the initial research hypotheses will be able to be tested.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

A solid state lithium metal battery based on a lithium garnet material was developed, constructed and tested. Specifically, a porous-dense-porous trilayer structure was fabricated by tape casting, a roll-to-roll technique conducive to high volume manufacturing. The high density and thin center layer (< 20 μm) effectively blocks dendrites even over hundreds of cycles. The microstructured porous layers, serving as electrode supports, are demonstrated to increase the interfacial surface area available to the electrodes and increase cathode loading. Reproducibility of flat, well sintered ceramics was achieved with consistent powderbed lattice parameter and ball milling of powderbed. Together, the resistance of the LLCZN trilayer was measured at an average of 7.6 ohm-cm2 in a symmetric lithium cell, significantly lower than any other reported literature results. Building on these results, a full cell with a lithium metal anode, LLCZN trilayer electrolyte, and LiCoO2 cathode was cycled 100 cycles without decay and an average ASR of 117 ohm-cm2. After cycling, the cell was held at open circuit for 24 hours without any voltage fade, demonstrating the absence of a dendrite or short-circuit of any type. Cost calculations guided the optimization of a trilayer structure predicted that resulting cells will be highly competitive in the marketplace as intrinsically safe lithium batteries with energy densities greater than 300 Wh/kg and 1000 Wh/L for under $100/kWh. Also in the pursuit of solid state batteries, an improved Na+ superionic conductor (NASICON) composition, Na3Zr2Si2PO12, was developed with a conductivity of 1.9x10-3 S/cm. New super-lithiated lithium garnet compositions, Li7.06La3Zr1.94Y0.06O12 and Li7.16La3Zr1.84Y0.16O12, were developed and studied revealing insights about the mechanisms of conductivity in lithium garnets.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The influence of particles recycling on the geochemistry of sediments in a large tropical dam lake in the Amazonian region, Brazil. Article in Journal of South American Earth Sciences 72 · December 2016 DOI: 10.1016/j.jsames.2016.09.012 1st Rita Fonseca 16.85 · Universidade de Évora 2nd Catarina Pinho 3rd Manuela Oliveira 22.6 · Universidade de Évora Abstract As a result of over-erosion of soils, the fine particles, which contain the majority of nutrients, are easily washed away from soils, which become deficient in a host of components, accumulating in lakes. On one hand, the accumulation of nutrients-rich sediments are a problem, as they affect the quality of the overlying water and decrease the water storage capacity of the system; on the other hand, sediments may constitute an important resource, as they are often extremely rich in organic and inorganic nutrients in readily available forms. In the framework of an extensive work on the use of rock related materials to enhance the fertility of impoverish soils, this study aimed to evaluate the role on the nutrients cycle, of particles recycling processes from the watershed to the bottom of a large dam reservoir, at a wet tropical region under high weathering conditions. The study focus on the mineralogical transformations that clay particles undergo from the soils of the drainage basin to their final deposition within the reservoir and their influence in terms of the geochemical characteristics of sediments. We studied the bottom sediments that accumulate in two distinct seasonal periods in Tucuruí reservoir, located in the Amazonian Basin, Brazil, and soils from its drainage basin. The surface layers of sediments in twenty sampling points with variable depths, are representative of the different morphological sections of the reservoir. Nineteen soil samples, representing the main soil classes, were collected near the margins of the reservoir. Sediments and soils were subjected to the same array of physical, mineralogical and geochemical analyses: (1) texture, (2) characterization and semi-quantification of the clay fraction mineralogy and (3) geochemical analysis of the total concentration of major elements, organic compounds (organic C and nitrogen), soluble fractions of nutrients (P and K), exchangeable fractions (cation exchange capacity, exchangeable bases and acidity) and pH(H2O).

Relevância:

100.00% 100.00%

Publicador:

Resumo:

In photovoltaic, fuel cells and storage batteries, the low output DC voltage should be boosted. Therefore, a step-up converter is necessary to boost the low DC voltage for the DC link voltage of the inverter. The main contribution of this chapter is to electrical energy conversion in renewable energy systems based on multilevel inverters. Different configuration of renewable energy systems based on power converters will be discussed in detail. Finally, a new single inductor Multi-Output Boost (MOB) converter is proposed, which is compatible with the diode-clamped configuration. Steady state and dynamic analyses have been carried out in order to show the validity of the proposed topology. Then the joint circuit of the proposed DC-DC converter with a three-level diode-clamped converter is presented in order to have a series regulated voltage at the DC link voltage of the diode-clamped inverter. MOB converter can boost the low input DC voltage of the renewable energy sources and at the same time adjust the voltage across each capacitor to the desired voltage levels, thereby solving the main problem associated with capacitor voltage imbalance in this type of multilevel converter.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

In standard laboratory consolidation tests, only the fraction of soil passing through a particular size of the sieve, called the matrix material, is used. This size is usually restricted to 1/10 of the height of the consolidation ring. Particles larger than this size that are removed before the test may consist of gravel, fragments of rock, or other coarse materials. Hence, it is not possible to estimate the compressibility and permeability of the total material based on the compressibility and permeability behavior obtained from laboratory consolidation tests on the matrix material. In the present investigation an attempt has been made to estimate the compressibility and permeability behavior of the total material based on the compressibility and permeability behavior of the matrix material. The results indicate that the presence of coarse particles will reduce the compressibility of the soil in proportion to the coarse fraction present in the whole soil and will not affect the permeability of the soil for the range investigated. If the coarse fraction exceeds the Limiting percentage, the void ratio-vertical effective stress path will also start to deviate from the predicted path. An expression has been developed to estimate approximately the deviating pressure, and it is found to depend on the soil type as well as the percent clay fraction.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

A new quaternary fast-ion conducting silver molybdo-arsenate [Agl-Ag2O-(MoO3 + As2O5)] (SMA) glassy system has been prepared using the melt-quenching technique for various dopant salt (Agl) concentrations by fixing the formers (MoO3 + As2O5) composition and the modifier (Ag2O) to formers (M/F) ratio. The prepared compounds were characterized by X-ray diffraction. The impedance measurements were made on different Agl compositions of the SMA glasses as a function of frequency (6.5 Hz-65 kHz) and temperature (303-343 K), using the Solatron frequency-response analyser(model 1250). The bulk conductivity and the appropriate physical model (equivalent circuit) of the SMA glass were obtained from the impedance analysis. The a.c. conductivity was calculated for different Agl compositions of SMA glasses at various temperatures and the obtained a.c. conductivity results were analysed using Jonscher's Universal Law. The conduction mechanism for the highest conducting SMA glassy compound has been explained using the diffusion path model.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The subject of the thesis is the mediated construction of author images in popular music. In the study, the construction of images is treated as a process in which artists, the media and the members of the audience participate. The notions of presented, mediated and compiled author images are used in explaining the mediation process and the various authorial roles of the agents involved. In order to explore the issue more closely, I analyse the author images of a group of popular music artists representing the genres of rock, pop and electronic dance music. The analysed material consists mostly of written media texts through which the artists authorial roles and creative responsibilities are discussed. Theoretically speaking, the starting points for the examination lie in cultural studies and discourse analysis. Even though author images may be conceived as intertextual constructions, the artist is usually presented as a recognizable figure whose purpose is to give the music its public face. This study does not, then, deal with musical authors as such, but rather with their public images and mediated constructions. Because of the author-based functioning of popular music culture and the idea of the artist s individual creative power, the collective and social processes involved in the making of popular music are often superseded by the belief in a single, originating authorship. In addition to the collective practices of music making, the roles of the media and the marketing machinery complicate attempts to clarify the sharing of authorial contributions. As the case studies demonstrate, the differences between the examined author images are connected with a number of themes ranging from issues of auteurism and stardom to the use of masked imagery and the blending of authorial voices. Also the emergence of new music technologies has affected not only the ways in which music is made, but also how the artist s authorial status and artistic identity is understood. In the study at hand, the author images of auteurs, stars, DJs and sampling artists are discussed alongside such varied topics as collective authorship, evaluative hierarchies, visual promotion and generic conventions. Taken altogether, the examined case studies shed light on the functioning of popular music culture and the ways in which musical authorship is (re)defined.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Music as the Art of Anxiety: A Philosophical Approach to the Existential-Ontological Meaning of Music. The present research studies music as an art of anxiety from the points of view of both Martin Heidegger s thought and phenomenological philosophy in general. In the Heideggerian perspective, anxiety is understood as a fundamental mode of being (Grundbefindlichkeit) in human existence. Taken as an existential-ontological concept, anxiety is conceived philosophically and not psychologically. The central research questions are: what is the relationship between music and existential-ontological anxiety? In what way can music be considered as an art of anxiety? In thinking of music as a channel and manifestation of anxiety, what makes it a special case? What are the possible applications of phenomenology and Heideggerian thought in musicology? The main aim of the research is to develop a theory of music as an art of existential-ontological anxiety and to apply this theory to musicologically relevant phenomena. Furthermore, the research will contribute to contemporary musicological debates and research as it aims to outline the phenomenological study of music as a field of its own; the development of a specific methodology is implicit in these aims. The main subject of the study, a theory of music as an art of anxiety, integrates Heideggerian and phenomenological philosophies with critical and cultural theories concerning violence, social sacrifice, and mimetic desire (René Girard), music, noise and society (Jacques Attali), and the affect-based charme of music (Vladimir Jankélévitch). Thus, in addition to the subjective mood (Stimmung) of emptiness and meaninglessness, the philosophical concept of anxiety also refers to a state of disorder and chaos in general; for instance, to noise in the realm of sound and total (social) violence at the level of society. In this study, music is approached as conveying the existentially crucial human compulsion for signifying i.e., organizing chaos. In music, this happens primarily at the immediate level of experience, i.e. in affectivity, and also in relation to all of the aforementioned dimensions (sound, society, consciousness, and so on). Thus, music s existential-ontological meaning in human existence, Dasein, is in its ability to reveal different orders of existence as such. Indeed, this makes music the art of anxiety: more precisely, music can be existentially significant at the level of moods. The study proceeds from outlining the relevance of phenomenology and Heidegger s philosophy in musicology to the philosophical development of a theory of music as the art of anxiety. The theory is developed further through the study of three selected specific musical phenomena: the concept of a musical work, guitar smashing in the performance tradition of rock music, and Erik Bergman s orchestral work Colori ed improvvisazioni. The first example illustrates the level of individual human-subject in music as the art of anxiety, as a means of signifying chaos, while the second example focuses on the collective need to socio-culturally channel violence. The third example, being music-analytical, studies contemporary music s ability to mirror the structures of anxiety at the level of a specific musical text. The selected examples illustrate that, in addition to the philosophical orientation, the research also contributes to music analysis, popular music studies, and the cultural-critical study of music. Key words: music, anxiety, phenomenology, Martin Heidegger, ontology, guitar smashing, Erik Bergman, musical work, affectivity, Stimmung, René Girard

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Aim of this study is to investigate composition of the crust in Finland using seismic wide-angle velocity models and laboratory measurements on P- and S-wave velocities of different rock types. The velocities adopted from wide-angle velocity models were compared with laboratory velocities of different rock types corrected for the crustal PT conditions in the study area. The wide-angle velocity models indicate that the P-wave velocity does not only increase step-wise at boundaries of major crustal layers, but there is also gradual increase of velocity within the layers. On the other hand, the laboratory measurements of velocities indicate that no single rock type is able to provide the gradual downward increasing trends. Thus, there must be gradual vertical changes in rock composition. The downward increase of velocities indicates that the composition of the crust becomes gradually more mafic with increasing depth. Even though single rock types cannot simulate the wide-angle model velocities, it can be done with a mixture of rock types. There are a large number of rock type mixtures giving the correct P-wave velocities. Therefore, the inverse solution of rock types and their proportions from velocities is a non-unique problem if only P-wave velocities is available. Amount of the possible rock type mixtures can be limitted using S-wave velocities, reflection seismic results and other geological and geophysical results of the study area. Crustal model FINMIX-2 is presented in this study and it suggest that the crustal velocity profiles can be simulated with rock type mixtures, where the upper crust consists of felsic gneisses and granitic-granodioritic rocks with a minor contribution of quartzite, amphibolite and diabase. In the middle crust the amphibolite proportion increases. The lower crust consists of tonalitic gneiss, mafic garnet granulite, hornblendite, pyroxenite and minor mafic eclogite. This composition model is in agreement with deep crustal kimberlite-hosted xenolith data in eastern Finland and reflectivity of the FIRE (Finnish Reflection Experiment). According to FINMIX-2 model the Moho is deeper and the crustal composition is a more mafic than an average global continental model would suggest. Composition models of southern Finland are quite similar than FINMIX-2 model. However, there are minor differencies between the models, which indicates areal differences of composition. Models of northern Finland shows that the crustal thickness is smaller than southern Finland and composition of the upper crust is different. Density profiles calculated from the lithological models suggest that there is practically no density contrast at Moho in areas of the high-velocity lower crust. This implies that crustal thickness in the central Fennoscandian Shield may have been controlled by the densities of the lower crustal and upper mantle rocks.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

A common-mode (CM) filter based on the LCL filter topology is proposed in this paper, which provides a parallel path for ground currents and which also restricts the magnitude of the EMI noise injected into the grid. The CM filter makes use of the components of a line to line LCL filter, which is modified to address the CM voltage with minimal additional components. This leads to a compact filtering solution. The CM voltage of an adjustable speed drive using a PWM rectifier is analyzed for this purpose. The filter design is based on the CM equivalent circuit of the drive system. The filter addresses the adverse effects of the PWM rectifier in an adjustable speed drive. Guidelines are provided on the selection of the filter components. Different variants of the filter topology are evaluated to establish the effectiveness of the proposed circuit. Experimental results based on EMI measurement on the grid side and the CM current measurement on the motor side are presented. These results validate the effectiveness of the filter.